Engine won't reach 2000 RPMs under load

[jangell]

Symptoms:
I took the car out a couple of weeks ago, and had a problem where the car wouldn't go over ~3000 RPMs. It sounded like one of the cylinders wasn't firing (to my untrained ear). After about 5 minutes of driving it cleared up and ran fine for the next 40 minutes or so.

That afternoon I took the car out again and had the same problem, but this time for more like 25 minutes. I had turned around and almost made it home before it cleared up, at which point I went back out to my appointment. On the way home two hours the symptoms returned, but again cleared up when I made it most of the way home.

Three days ago I tried to take it out, and it wouldn't easily go over 1500 RPMs with the pedal to the floor. I went just a few hundred feet before I turned around.

I took it out again today, and had the same problem -- I couldn't get over 1500 RPMs. The car seemed to idle OK, but it was clearly rougher than it should be (I'm guessing that with no load the engine didn't have as much trouble with one or two cylinders not contributing). Under load it is obvious that there is no power and you can more hear the unevenness (I think of it as a repeating "machine gun" sound, rather than the smoother engine noise I expect), more so than when you try to rev it at idle.


What I've Tried So Far:
I'm in my condo parking lot, so I'm a bit limited about what I can do (I rent a garage to do real work, but there's no way I could make the 20 minute drive there in this condition).

- I used a timing light to test for spark on all six wires -- the light flashed as expected. I also used an inline spark tester on cylinders 1, 2, 3 and 6 (the easy ones to get to) before I remembered I had that timing light.

- I attempted to test the fuel injectors for spray, but clearly I'm doing something wrong as I got no fuel at all out of them. I pulled out injectors 1, 2, 3 and 6, put them in jars, turned the key to "run", and jumped pins 30 and 87 on the RPM relay socket. I could clearly hear the pump running, but no fuel came out of the injectors -- not even a dribble. The car started right up once I put the injectors back in, though. Any idea what I'm doing wrong here?

- The car has ~1/8 tank of gas and a freshly-charged battery. Fuel pump is ~10 years old.

- The top of the engine was overhauled by myself and a friend about a year and half ago. The wires and distributor cap are fairly new (at most 5 years old). Fuel accumulator is ~7 years old. The fuel distributor is ~10 years old. The WUR is probably about the same age, maybe a bit newer.


Anyone have any ideas about what I should try next? I'm leaning towards one or more clogged injectors, but I can't seem to figure out how to do the test properly. While I'm tempted to use this as an excuse to do my long-planned EFI conversion, I'd rather just get the car running reliably again for now.

Thanks!

-- Joe

[Bitsyncmaster]

You need to start with testing fuel pressures. It sounds like that is your problem. Could be fuel pump, fuel filter, PPR o-ring. But the pressure testing will help you find it.

[Spittybug]

Inspect the plugs for cracks in the ceramic. Sometimes under load they will arc to ground and not fire, giving that "miss" feeling you described. When tested at idle, they can appear fine. In my experience, intermittent problems are most often electric in nature.

[jangell]

Thanks guys.

I think I'll test the fuel pressure first, since that seems simplest and quickest, and I happen to have a test kit. I'll only be able to test primary pressure right now, though; I'd rather not test the control pressure if it requires that I run the car in the parking lot for 15 minutes and bug the neighbors with engine noise.

I should mention that when I low RPM problems cleared themselves up, the car had been at operating temperature for some time (for example, 25 minutes of driving around), which implied to me that it wasn't an issue of with the engine being cold. Unfortunately, with the low RPMs I'm getting now I won't be able to safely drive it anywhere to see if the problem clears up when it gets warm.

Also, the car does start very quickly when I turn the key, which at least suggests I'm not having a leak-down issue or cold-start issue. Still, I suppose that whatever pressure I do have many only be enough to keep the idle, and that's it.

While I'm doing the primary pressure test, I'll clean out the screens on the CPR, just in case that's the problem.

Can anyone confirm that I was doing the fuel injector spray test correct? Pull the injectors, turn the key to "run", jump the RPM relay -- but no fuel came out. The car actually starts and runs (albeit with the aforementioned issues), so the injectors must be working to some degree.

I'll try to check the spark plugs next. At least four of them are easy enough to get to, anyway. The plugs are about a year and a half old, but that doesn't mean they haven't failed on me.

I hope to be able to do at least one of these tests in the morning. Thanks!

-- Joe

[David T]

You have to push the air sensor plate down at least a little to get the injectors to squirt. My first guess would be one or more dirty injectors. It is not just getting the same amount of fuel out of each one, you need to have a good pattern too. If one or more are squirting jets out instead of droplets that cylinder will run rough. I would not bother checking pressures, if the pressures were off the motor would not run right at all. I WOULD pull the fuel pump and inspect the fuel tank and all of the parts in there. All too often fuel system problems start in the tank. If it is dirty in there or you have water or deteriorated parts you will never get the motor to run right.
David Teitelbaum

[jangell]

You have to push the air sensor plate down at least a little to get the injectors to squirt.

Ah! I knew I was forgetting something. I decided to try this test first, since it's the easiest and I forgot that I don't have any more crush washers for when I do a pressure test.

When I did the test properly, the injectors seemed to be spraying, but not ideally. For example, one injector sprayed five evenly-spaced jets of fuel, but I think there are supposed to be 8 or 10 jets, because all of the five jets were in a half-ring on one side of the injector while it dripped a little from the other half. Admittedly, the injectors were lying on their sides inside glass containers (I need some test tubes or something so I can place them vertically), and I don't know if that was influencing it the spray pattern -- I don't think so, though, since the jets that were firing were going upward, while it was only dripping downward a little. Also, I hate injector 4; took me about half an hour to get that damn clip off.


My first guess would be one or more dirty injectors. It is not just getting the same amount of fuel out of each one, you need to have a good pattern too. If one or more are squirting jets out instead of droplets that cylinder will run rough.

I may not understand what injector spray is supposed to look like. At no point did I notice any kind of fine mist per say, but rather a series of jets on all of the injectors. I assumed that a ring of jets was correct, but I checked YouTube and found some videos showing very fine mists, which is definitely not what I'm seeing.

I can try to take a picture or video if that would help visualize it better. I'm tempted to replace all the injectors just to be sure -- or I was, until I realized they're $60 a pop. Gah.


I WOULD pull the fuel pump and inspect the fuel tank and all of the parts in there. All too often fuel system problems start in the tank. If it is dirty in there or you have water or deteriorated parts you will never get the motor to run right.

That's something I can't get away with doing in the parking lot; I'll have to get the car to the garage to do that, if I can figure out how I'm going to get it there. My fuel sender is starting to fail, so this might be a good excuse to get DMCH's new sender/pump combo.

About 8 years ago I did have some bad gas that gave similar symptoms, although more severe. It wound up wrecking the fuel distributor, which is how I found out how much those cost. That was the last time I cleaned out the fuel tank, although I left the fuel pump alone, which was about 2-3 years old at the time.

Thanks!

-- Joe

[David T]

The fuel should come out of each injector in a mist with no streams, lines, or jets of spray. It should come out in a circular, cone-shaped mist. When you release the air sensor plate the injectors should not leak or dribble. Understand testing injectors in this manner is very crude. It can't tell you what pressure they crack open at or spray at. That can only be done in a tester. If they are not spraying a good pattern or leaking they should be removed and cleaned.
David Teitelbaum

[jangell]

The fuel should come out of each injector in a mist with no streams, lines, or jets of spray. It should come out in a circular, cone-shaped mist. When you release the air sensor plate the injectors should not leak or dribble. Understand testing injectors in this manner is very crude. It can't tell you what pressure they crack open at or spray at. That can only be done in a tester. If they are not spraying a good pattern or leaking they should be removed and cleaned.
David Teitelbaum

Ok, I'll do a few more tests this afternoon to confirm what I was seeing, and I'll try to take some pictures and video, although I imagine they won't be very high quality (small subjects with fast motion). I was pushing the plate down pretty far to see if I could get it to mist, but it didn't seem to want to do it. I can also confirm that at least one injector was dribbling when I released the plate.

It's not clear to me how the injectors would be cleaned, or where I would get them cleaned, since that seems like it might be a lot more affordable than replacing them. Any ideas there?

Thanks!

-- Joe

[David T]

The injectors can be cleaned and tested in the cleaner/tester. Every vender has one and so do many Volvo dealers (if they can find it and remember how to use it!). There is a picture of it in the Workshop Manual.
David Teitelbaum

[Ron]

$ .02

History has shown that you will be VERY lucky if send them off and get them cleaned and not have problems.

[jangell]

The injectors can be cleaned and tested in the cleaner/tester. Every vender has one and so do many Volvo dealers (if they can find it and remember how to use it!). There is a picture of it in the Workshop Manual.

So, not likely something that I can get done locally here in southern Massachusetts, then. :)


History has shown that you will be VERY lucky if send them off and get them cleaned and not have problems.

Hmm... maybe I should just bite the bullet and get a new set. I guess I can always get the old ones cleaned and keep them as spares, depending on how much that costs.

I shot some video of the injectors on 2 and 3, and I'd say they look pretty bad.



http://www.youtube.com/watch?feature=player_embedded&v=8Uti-FKcZA8

As you can see, they're spraying jets of fuel, not a fine mist. Also, the injectors are dripping when the plate is closed. Although I only shot video of the two injectors, the others were similar when I looked at them earlier.

Also, this is an image of the fuel that came out of the injectors. Both images are looking down into the glass, which is itself tipped so I could aim the camera. The milky white stuff is curious.

2051120512Cancel Changes (http://dmctalk.org/#)

Thanks again

-- Joe

[Bitsyncmaster]

Test your fuel pressure before you go and buy new injectors. If the pressure is low the spray will not look good.

[Ron]

Getting, "This video is private"
EDIT: Fixed


Pics- looks like there is water on my crappy monitor??

[jangell]

Getting, "This video is private"

Doh -- should be fixed.


Pics- looks like there is water on my crappy monitor??

It may be -- I don't actually know what water in gas looks like. Although about 8 years ago I had some bad gas; this is what I drained out of the tank back then:

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-- Joe

[David T]

Getting, "This video is private"

Pics looks like there is water on my crappy monitor??

Let the sprayed fuel settle and if water separates out you have to clean the tank out. Yes, if the pressure is low you will not get a good pattern but the injector is not supposed to open till the pressure is high enough for it to properly atomize the fuel. A dirty injector will open at a lower pressure and that is part of the reason it will have a bad pattern. You should not need an extra set of injectors. Once you have a good, clean set, you should be fine. As for cleaning injectors, I have been able to do it successfully and so have the venders. It is at least worth trying and any bad ones can be replaced. Worst case you may need to replace 1 or 2 but in all probability your old ones should clean up.
David Teitelbaum

[Ron]

Doh -- should be fixed.
One of us did...lol



It may be -- I don't actually know what water in gas looks like. Although about 8 years ago I had some bad gas; this is what I drained out of the tank back then:

2051320514

-- Joe

The last pic looks like a chocolate malt on my monitor. (Any one else?)
I'm thinking you need some serious fuel system cleaning... but from the looks of it here, I don't see it running smoothly at low RPM like you said earlier???
:hmm:

[jangell]

The last pic looks like a chocolate malt on my monitor. (Any one else?)
I'm thinking you need some serious fuel system cleaning... but from the looks of it here, I don't see it running smoothly at low RPM like you said earlier???

That last pic is from 8 years ago, when bad gas destroyed my fuel distributor. Thankfully the fuel doesn't look nearly as bad this time.

-- Joe

[Ron]

Sorry!...I skimmed over the note somehow. :blackeye:

[jangell]

Sorry!...I skimmed over the note somehow. :blackeye:

No problem -- I was sure someone was going to at some point anyway. :)

-- Joe

[jangell]

Test your fuel pressure before you go and buy new injectors. If the pressure is low the spray will not look good.

Ok, I just gave that a go, but I can't actually remember how to hook up my OTC 6550 Master Pressure Test Kit. I know it goes between the CPR and the fuel distributor, and I found the banjo bolt like adaptor -- I just can't figure out which piece I need to attach the fuel line to the tester. Maybe I'll try again tomorrow.

-- Joe

[jangell]

Once you have a good, clean set, you should be fine.

That's reassuring, at least.


As for cleaning injectors, I have been able to do it successfully and so have the venders. It is at least worth trying and any bad ones can be replaced. Worst case you may need to replace 1 or 2 but in all probability your old ones should clean up.

I'm certainly willing to try it; I don't suppose I could send my injectors to you for cleaning, could I?

I called Rob Grady to ask about injectors. He was also of the opinion that cleaning probably wouldn't work too well, but he also warned that he's heard that Bosch is discontinuing them and that it's going to become difficult to get new ones in the future.

Rob also agreed with others that the screen in the fuel tank was likely clogged, and suggested that I pull the pump and check. I haven't actually done this before, although he pointed out that it'll probably be a less suspicious job to the condo association than the fuel injector work, since it'll just look like I'm cleaning the trunk to a casual observer. I'd still like to limp it to the garage, if I can figure out how to get it up the short driveway and over the 1" lip without power.

Thanks!

-- Joe

[Silverbullet]

WOW.... You own a Delorean and don't have Triple A??????:hihi2:

Craig

[Ron]

Bosch is discontinuing them and that it's going to become difficult to get new ones in the future.

Bosch: 0437-502-013
Bosch: 0437-502-022-751-014

[Grover]

Check the connector to your CPR. I had one of the connectors back out and another time it was corroded through. It caused my care to accelerate VERY poorly and run as if a cylinder was missing. When hot, it ran slightly better but not great. Once I fixed the connector and had the correct signal running through the CPR it was better.

Also, a very fouled up O2 sensor may cause it as well I believe.

Just my 2 cents.

[jangell]

WOW.... You own a Delorean and don't have Triple A??????

AAA Plus. :) The actual problem is getting it INTO the garage. It's right at the edge of the sidewalk, has ~1" of lip between the sidewalk and the garage floor, and is up a slight incline. I think the turn is too tight for the tow truck to drop it right in the garage. I usually need to gun it a bit to get it over the lip, and at only 1500 RPMs that's not going to work. Although I have come up with a cunning plan: I pull up to the lip, then jack the car up, slide some boards under the wheels, and roll right off into the garage. Then I just have to repeat for the other tires. It should work, anyway...

I did want to do a winch, but at the moment the only thing I could attach it to would be the wall studs, and that doesn't seem wise...

-- Joe

[jangell]

Bosch: 0437-502-013
Bosch: 0437-502-022-751-014

I did see those in the cross reference. I'm kind of disappointed that I can't find a button to click to buy them online (or at least so I could see other prices on them), but that seems to be the way of such things. I'm guessing Houston still has them in stock, though.

-- Joe

[jangell]

Check the connector to your CPR. I had one of the connectors back out and another time it was corroded through. It caused my care to accelerate VERY poorly and run as if a cylinder was missing. When hot, it ran slightly better but not great. Once I fixed the connector and had the correct signal running through the CPR it was better.

That's interesting; I didn't think to look at that. I'll check it more thoroughly next time I'm at the engine bay.


Also, a very fouled up O2 sensor may cause it as well I believe.

My O2 sensors is about a year old (I replaced it when I put in a SPEC I exhaust), so I don't think it's that.

Thanks

-- Joe

[DMC5180]

Joe,

Unless you started with a dirty glass, that milky stuff in your wine glass is not fuel. Is the photo with the running fuel line current or 8 years old?

Do you live alone? Do you have more than one car? Is it a steep incline leading up too your garage floor? How long is the driveway length in front of the garage? The delorean rolls very easily with a couple people. slight inclines and the 1" lip should be now problem if you have any kind of rolling momentum. I have, in a pinch, loaded a car on trailer with Manual transmission just by cranking the Starter with it in first gear. I would think that if the car runs at all ,even if only 1500 rpm, you should be able to move it under its own power unless you have 20% up slope to you garage.

[jangell]

Unless you started with a dirty glass, that milky stuff in your wine glass is not fuel. Is the photo with the running fuel line current or 8 years old?

Hmm... I may have tainted the sample with the glass. After I'd used them the first time to test the injectors, I rinsed them out and left them in the sink. When I shot the video, I used the same still-wet glasses. It's quite possible that all the water came from there. I'll do another test tomorrow with clean, dry glasses to be sure. Sorry for the confusion.

The photo of the running fuel line and the jar full of fuel is what actually came out of my fuel system 8 years ago.


Do you live alone? Do you have more than one car? Is it a steep incline leading up too your garage floor? How long is the driveway length in front of the garage? The delorean rolls very easily with a couple people. slight inclines and the 1" lip should be now problem if you have any kind of rolling momentum. I have, in a pinch, loaded a car on trailer with Manual transmission just by cranking the Starter with it in first gear. I would think that if the car runs at all ,even if only 1500 rpm, you should be able to move it under its own power unless you have 20% up slope to you garage.

I live with my wife, but we're both kind of recluses, so we don't tend to have many people around to help us out, and the garage I rent is about 20 minutes away. I have pushed the car up a shallow incline with two or three people into my dad's garage before, but the lip on the rental garage combined with the slope of the sidewalk that you cross into the the garage is significant enough that I scrape the bottom of the car slightly pulling in (lowered front suspension; I have to back it in to clear the lip at all, and even then I put boards down that I crudely cut ramps into to make it easier to get up). Hmmm... perhaps it's a 2" lip; I never actually measured it...

We do have a "practical" car; I briefly considered pushing one car with another, but that seems like a bad idea. Also, I'm not sure there's enough room to line up the two cars; with my back wheels at the lip, the nose still sticks in the street a bit.

Mine's an automatic, so I can't use the starter trick to move it, but I'm impressed you could get it onto a car that way.

I have a rather poor correlation with how full the tank is to how poorly the car performs. I'm tempted to put five gallons of clean gas in it to see if I can get 3000 RPM, at which point I might be able to get the car to the garage under its own power. That'll have to wait until the weekend, though, and I'll have to drain it back out to clean the tank. Hopefully this heat wave will break by then...

-- Joe

[jangell]

I finally figured out how to use my fuel pressure test kit again (it's adaptors 76 and 77 in the OTC 6550 kit, in case anyone else needs it). The result is ~69 PSI (4.75 bar) with the valve closed, and ~47 PSI (2.5 bar) open (car off in both cases, full pump running via jumped RPM socket). It's a touch low, but pretty close to the 70-72 PSI listed in the workshop manual. It's ~92 degrees out today, although I imagine that would only affect how quickly the CPR warmed up. I didn't do the CPR pressure test.

I also kept the fuel that drained out of the pressure gauge. I let it sit for a while and took some pictures. Assuming that there wasn't bad gas in the pressure regulator, it looks like water(?) is mixed with the gas. Any idea how that even happens?

I pulled my injectors so I can send them off for cleaning, so I likely won't be trying to drive it to the garage this weekend, but I may try cleaning the fuel tank in the parking lot after all. I hear it can be tricky getting the fuel pump in correctly; guess I'll find out.

These picture show the gas/water(?) mix, the primary pressure reading, and the fuel injectors ready to be shipped out.

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Thanks again everyone. I'll report back once I have the car together again.

-- Joe

[Bitsyncmaster]

Yes that looks like water in the gas. Just like you would see when you preflight an airplane, you drain gas from the wing tanks into a container and look for clear liquid at the bottom.

You may have got some bad gas. You don't see water much anymore with the 10% alcohol in the gas. We use to use a can of "dry gas" in the old days.

[jangell]

You may have got some bad gas. You don't see water much anymore with the 10% alcohol in the gas. We use to use a can of "dry gas" in the old days.

I don't suppose simply draining the tank (say, by running the fuel pump until the lines are empty; there's maybe three or four gallons of gas in the tank now) and refilling it will be enough to clear it, will it? I would like to avoid cleaning the tank in the parking lot if at all possible.

Thanks

-- Joe

[Bitsyncmaster]

I don't suppose simply draining the tank (say, by running the fuel pump until the lines are empty; there's maybe three or four gallons of gas in the tank now) and refilling it will be enough to clear it, will it? I would like to avoid cleaning the tank in the parking lot if at all possible.

Thanks

-- Joe

The water would be sitting in the bottom of the tank. If its not much water it should get absorbed with gasohol.

[jangell]

The water would be sitting in the bottom of the tank. If its not much water it should get absorbed with gasohol.

Ok, I think I'll just put in new gas then, once I've drained the tank. I was thinking of throwing some dry gas in there anyway, but googling suggested that's moot since normal gas is 15% ethanol anyway.

Some day I have to replace my fuel sender (Tankzilla; it's being a little unreliable recently on the full end and takes a long time to get to "full", like its sticking, but it works well enough), at which point I'll probably do DMCH's new pump/sender combo and clean the tank out then.

Thanks!

-- Joe

[Bitsyncmaster]

Ok, I think I'll just put in new gas then, once I've drained the tank. I was thinking of throwing some dry gas in there anyway, but googling suggested that's moot since normal gas is 15% ethanol anyway.

Some day I have to replace my fuel sender (Tankzilla; it's being a little unreliable recently on the full end and takes a long time to get to "full", like its sticking, but it works well enough), at which point I'll probably do DMCH's new pump/sender combo and clean the tank out then.

Thanks!

-- Joe

FYI:
It's 10% ethanol. They know 15% will cause more problems than the 10% is causing now. Funny when I was in South Carolina two weeks ago I saw gas stations advertizing no ethanol gas. You can't get that here in souther Maryland.

[David T]

FYI:
It's 10% ethanol. They know 15% will cause more problems than the 10% is causing now. Funny when I was in South Carolina two weeks ago I saw gas stations advertizing no ethanol gas. You can't get that here in souther Maryland.

If you have water in the gas it is in the fuel tank. The only way to get rid of it is to siphon out everything in the tank and then wipe the tank out. It would make sense you are having trouble with the tank level sender because the water rusted the contact wires in the sender. You can remove it and clean the wires up with some fine sandpaper. Do NOT use "Dry Gas", you already have too much alcohol in the fuel. Don't use the fuel pump to drain the tank, running the dirt and water through it is not a good idea.
David Teitelbaum

[jangell]

If you have water in the gas it is in the fuel tank. The only way to get rid of it is to siphon out everything in the tank and then wipe the tank out. It would make sense you are having trouble with the tank level sender because the water rusted the contact wires in the sender. You can remove it and clean the wires up with some fine sandpaper. Do NOT use "Dry Gas", you already have too much alcohol in the fuel. Don't use the fuel pump to drain the tank, running the dirt and water through it is not a good idea.
David Teitelbaum

Right... This is what I was hoping to avoid, at least in the parking lot. I had hoped I could throw a few more gallons of gas in there to dilute the water sufficiently to limp it to the garage, at which point I'd be free to do whatever repairs I need to do. I'd be doing that with newly-cleaned injectors, though, which would probably not be good for them.

At least it sounds like the fuel sender is salvageable.

-- Joe

[David T]

Right... This is what I was hoping to avoid, at least in the parking lot. I had hoped I could throw a few more gallons of gas in there to dilute the water sufficiently to limp it to the garage, at which point I'd be free to do whatever repairs I need to do. I'd be doing that with newly-cleaned injectors, though, which would probably not be good for them.

At least it sounds like the fuel sender is salvageable.

-- Joe
Doing the fuel tank is not that big a deal. You do it all from the top. Since it is the front of the car no one will even suspect you are working on the fuel tank unless they get close and smell fuel. If you are pumping water there is way too much to dilute. Get the tank empty, wipe it out, and inspect all of the parts. Replace any deteriorated or questionable parts. You will not have a reliable fuel system till you have a clean tank with good parts in it. Any residue or coating in the tank can be cleaned up with Acetone. Once you are done in the tank replace the fuel filter.
David Teitelbaum

[jangell]

Doing the fuel tank is not that big a deal. You do it all from the top. Since it is the front of the car no one will even suspect you are working on the fuel tank unless they get close and smell fuel. If you are pumping water there is way too much to dilute. Get the tank empty, wipe it out, and inspect all of the parts. Replace any deteriorated or questionable parts. You will not have a reliable fuel system till you have a clean tank with good parts in it. Any residue or coating in the tank can be cleaned up with Acetone. Once you are done in the tank replace the fuel filter.

Hmmm... Ok, maybe ill give it a go later this week. I can use a hand pump to remove the last couple of gallons of gas. It looks easy enough to pull the pump out. After that it seems like I can get it to the garage to replace the fuel filter and any other parts I may need to replace in the tank itself.

Thanks for all the help.

-- Joe

[jangell]

I finally took car of the tank today. Dave T graciously cleaned my injectors for me; he said they were the worst he'd ever seen, and that one of them was completely bad, while the others were passable after cleaning. I got a new injector and boots from DMC MW, and a bunch of copper washers from McMaster-Carr.

After I put the injectors back in, I pulled the fuel pump and drained 3 gallons of gas with a simple siphon pump thing. and got the rest out with some rags. The tank was remarkably clean already; there wasn't really any gunk to speak of, although the surface was slightly slick to the touch (I figure that was from the gas). I do plan on doing a more thorough cleaning this weekend, just in case.

I'm much more concerned about the top of the fuel pump outside the tank. The cover seemed to be doing nothing -- it was filled with water, and the fittings are all rusted. I'm not sure if this is how water was getting in, but it certainly wouldn't surprise me. At this point I'm trying to decide if I should do a complete pump replacement with one from DMCH, or if I should just replace the boot and cover. It's not clear to me how I'd get those rusted bolts off the fuel pump, however, and the docs from the new pump seem to suggest that you cut the lines instead; is that really correct?

After I put 2.5 gallons of clean gas in the tank, it took me about 10 minutes to get the car started. This included trying to jump the RPM relay socket directly to run the pump, although I could hear it running for a couple seconds when I turned the key to "run". I got a cloud of white smoke when it finally did start, but that quickly cleared up and the car ran pretty well, and got smoother after I let it run a bit longer. I only drove it for about a mile (down the street and back), and it ran very well. I thought there was a little hesitation or misfiring once or twice, but I get the feeling it'll get better once I drive it for a longer distance and put more gas in it. Overall, it's MUCH better than before; revving from idle had no problem getting to high RPMs with no misfirings.

The only other problem i had was that I forgot to remove the torque wrench that was laying on the passenger windshield wiper; I thought the "pop" I heard while driving was from the exhaust, until I realized that it was the wrench's plastic case sliding off the car and hitting the ground. :)

I've attached some pictures of what I found.

Fuel Pump Cover and Rubber Seal
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Siphoning Gas. I had to tape one end of the hose to a prybar (the red handle in the picture) to get it to stay in the tank, and tape the other end to the gas can.
2069620697

The tank itself. Apologies for the quality of the photos; my iPhone's lens isn't quite as wide as it really needs to be to do this properly.
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I also pulled the fuel sender, which contrary to my previous assertion is not a Tankzilla but a DMCH unit. I was going to try to take it apart and clean it, but I couldn't actually figure out how to do that beyond removing the two screws on the bottom, so I decided to leave it alone. There's a small amount of corrosion on the button of the sender. The seal at the top is coming apart a little bit on the sender as well, which perhaps could also be the source of a water leak into the tank. Fixing the fuel sender is another reason I'm considering the new DMCH pump kit.
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So, here's today's questions:

- How do I safely dispose of three gallons of bad gas? It's currently sitting in a proper gas can under my deck, but I'd like to dispose of it properly. I live in a condo, so burning it, using it in gas-poewred tools (of which I have none), or anything like that aren't really an option. I disposed of the rags by letting them dry in the sun a bit while I was working, then putting them in a paint can and filling it with water per some instructions I found online.

- Do you actually cut the fuel lines on the top of the pump (as in, outside of the pump, before you remove it from the tank) when replacing it? I just want to make sure I don't screw up anything here, and it would save me the trouble of figuring out how to get that rusted hardware out.

Thanks!

-- Joe

[David T]

Some neighborhood gas station should be able to dispose of the fuel for you. If you try to disassemble that pump you will break everything. The water may have gotten in because the cover boot is bad. It may make sense to check what it costs to go with the new integrated unit rather than trying to fix up what you have. Sounds like you are close to having a good fuel system. After you drive the car and go through a few gallons of gas you should change the fuel filter.
David Teitelbaum

[jangell]

Thanks Dave; I'll swing by the shop that takes care of my practical car and ask them about the gas. I'm not sure I'd be able to get the cover off without taking those rusted fittings out as well, so I think I've decided to replace the whole thing. I've put in an order for Houston's pump/sender kit, and I hope to install that this weekend if it comes in time; otherwise, it'll be next weekend. The kit comes with a fuel filter, so I'll do that at the same time.

Thanks!

-- Joe

[jawn101]

That tank doesn't look clean to me, it still looks gritty. Maybe it's just the photos but if you feel even a speck of debris on the plastic you need to keep cleaning.

[jangell]

There was what I'd call a "texture" on the tank, like seams or zipper tracks, which I assumed had to do with the fiberglassing process, as they looked too regular to be debris. Looking at the photos again, though, I see what you mean about the "grittiness". I'm trying to decide if that was a side effect of the flash. I was expecting sludge and other residue, so that may have tainted how I looked at the photos. Maybe I can drop a light in the tank and use use Facetime to stream video from my iPhone to my iPad so I can do a more accurate, realtime survey.

To be honest, without a truly clean tank to compare with, it's not entirely clear to me how clean is "clean'. Still, I'm going to do a thorough acetone cleaning once I get the new fuel pump, since then the old baffle will be out of the way.

Thanks for spotting that.

-- Joe

[jawn101]

There was what I'd call a "texture" on the tank, like seams or zipper tracks, which I assumed had to do with the fiberglassing process, as they looked too regular to be debris. Looking at the photos again, though, I see what you mean about the "grittiness". I'm trying to decide if that was a side effect of the flash. I was expecting sludge and other residue, so that may have tainted how I looked at the photos. Maybe I can drop a light in the tank and use use Facetime to stream video from my iPhone to my iPad so I can do a more accurate, realtime survey.

To be honest, without a truly clean tank to compare with, it's not entirely clear to me how clean is "clean'. Still, I'm going to do a thorough acetone cleaning once I get the new fuel pump, since then the old baffle will be out of the way.

Thanks for spotting that.

-- Joe

I'm totally with you on the difficulty of getting a good photo. That's why I'll caveat the one I'm including here with "I was flying blind when I took it..."

Here's my tank before cleaning. This picture does a better job of showing the grit than yours did, but I have a feeling in real life they are very similar:
http://dmctalk.org/attachment.php?attachmentid=20717&d=1374699818


And here's what my tank looked like after a good cleaning - completely emptying it of gas, allowing it to dry, wiping out the grit with a clean towel, scrubbing with acetone, drying, scrubbing, and drying again. Then I blew it out with compressed air and vacuumed it one more time:
http://dmctalk.org/attachment.php?attachmentid=20718&d=1374699819

Does that help set some expectations up? I feel like I did a pretty good job with my cleaning.

[DMCMW Dave]

There was what I'd call a "texture" on the tank, like seams or zipper tracks, which I assumed had to do with the fiberglassing process, as they looked too regular to be debris. Looking at the photos again, though, I see what you mean about the "grittiness". I'm trying to decide if that was a side effect of the flash. I was expecting sludge and other residue, so that may have tainted how I looked at the photos. Maybe I can drop a light in the tank and use use Facetime to stream video from my iPhone to my iPad so I can do a more accurate, realtime survey.

To be honest, without a truly clean tank to compare with, it's not entirely clear to me how clean is "clean'. Still, I'm going to do a thorough acetone cleaning once I get the new fuel pump, since then the old baffle will be out of the way.

Thanks for spotting that.

-- Joe

Clean is as if you could eat off of it. No grit is acceptable. The other comparison photo put up here is accurate. Once you are all done you probably ought to replace the filter too, that will also hold water.

You need to get the water out of the tank completely or you will continue to be buying fuel injectors.

Nobody has mentioned it but the cover on your pump appear to be completely missing, and that is how the water is/was getting in. Water from the windshield is strategically funneled to the top of the pump. So having the cover tight and in place is imperative.

[jangell]

Well, crap.

I took the car out this morning to get gas. Everything seemed fine until I turned off of my fairly level road and went up a slight hill. The engine sounded like it was misfiring again, and I heard a few "pops" from the exhaust. I didn't make it to the gas station (I wasn't sure I could get up to 45 MPH speed limit on that road, so I turned around and came home). My quick jaunt yesterday where everything seemed fine was on my level, low-speed-limit road. I'm starting to think the pop I heard yesterday that I attributed to a torque wrench falling off the hood was indeed from the exhaust.

The car revs fine at idle, although without a load I imagine that is much easier for it (not knowing a whole lot about engines, I'm guessing that the inertia from the previous cylinder firing is enough to get it past the non-firing cylinder to the next cylinder). It doesn't shake around as much at idle as it had before, either.

When driving, though, it clearly sounds like it's missing (the engine isn't as smooth as it should be, with a "gap" in the engine sound where one of the cylinders appears to not be firing), and a noticeable loss of power. Top RPMs under load was around 2500. I only have ~2 gallons of gas in the tank at the moment. Fuel pressure seemed fine when I tested it last week (~69 PSI). I didn't let the car warm up, so I can't say if this is a CPR issue; but I could drive it around a bit more if anyone thinks it would help.

To clarify: It's better than before, but definitely not enough to drive it in any real sense.

I'm thinking of pulling the plugs and seeing if they're firing but dirty, unless anyone has another idea of what I can try next.

Thanks!

-- Joe

[David T]

With only 2 gallons in the tank even a slight hill can be enough to lose fuel pressure especially if any of the parts in the tank are deteriorated, bad or misplaced.
David Teitelbaum

[jangell]

Once I was back on level ground I was still having this loss of power and misfiring if I tried to rev the engine, so I'm not totally sure about it just being low on fuel. Back when I first got the car the pickup line was incorrectly installed, and the car would struggle badly and sometimes stall trying to go up a hill when I had less than half a tank of gas, but clear up on level or downhill travel. This seems to be a bit more consistent. Clearly I should have taken it on more of a test drive yesterday. At least it's nice and cool out today...

I can limp it to the gas station, I guess; my wife has taken out the practical car today, so I can't fill up a gas can and run it back. I was trying to get the car running by today so that I could take it out to an appointment while my wife had the other car.

-- Joe

[Spittybug]

:popcorn:

My money is still on electrical. Cracked insulators, cracked distributor cap or bad coil. Looks like you really needed to do the gas stuff too though....

[jangell]

Yeah, I'm going to look at the plugs now, at least. The distributor is pretty new, although I'm mostly hoping it isn't that's because of how hard it is to access.

I did discover that I forgot to reconnect the idle air motor, which probably explains why I had so much trouble starting it yesterday.

Once I plugged that back in, I started the car, put it in reverse, and revved it while holding down the brake pedal. -- maxed at 1500 RPM and was clearly missing (by the sound of the engine). Not that I expected the idle motor to affect the car when it's not at idle.

I guess there's no easy way to tell which cylinder is missing, is there?

Thanks again

-- Joe

[Ron]

Pull the plug wires one at a time while listening to the engine. If you get to one that doesn't change anything, that's probably it.
(probably #4 or #5 ;-) Sometimes a high idle will help you hear the difference.

[jangell]

Here's a picture of the injectors as pulled from the engine. From left to right: 3, 2, 1, 6, 5, 4:

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The last picture shows just 6, 5 and 4. It's hard to see, but as Ron predicted, 4 and 5 are the worst. :). The debris around the top of 5 seems to be a crushed leaf; apparently I let one get in there when I installed these last year.

The ceramic looks good on all of the plugs.

Is there anything I should do to clean them, or should I replace any? Some are blackened, but I don't know if that means that they're bad or just wearing.

Thanks!

-- Joe

[jangell]

Here's some hopefully better close ups of the injectors. First is 3, 2, 1, then 6, 5, 4.

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Odd how smoothly they transition from grey to black-ish in the order I happened to pull them from the engine.

-- Joe

[jangell]

Based on some YouTube videos, I cleaned the plugs with a wire brush and sand paper and put them back in the engine. I did not put them back in the same ports -- I basically swapped the left and right sides, so that the dirtiest injectors were the easiest to reach.

Fired the car up -- same problem.

I tried pulling some plugs wires while the car was idling, but there was nothing conclusive -- the engine firing always seemed to change a bit. I didn't try all of them, as I think I'm already pressing my luck with doing work in the parking lot, and it's harder to ignore with a loud engine running.

I'm not quite sure what to test next.

-- Joe

[Ron]

You probably should of replaced them (Go BOSCH)...you never know if one is beyond cleaning AND looking at new plugs after a short run can tell you A LOT.

You could of tried a poor mans test by connecting them to the coil wire and looking for a nice hot spark after cleaning them....

To answer previous question, the black is not age, it is unburnt fuel/oil (running rich).

Put some gas in it LOL

[jangell]

The good news is that the car is running JUST well enough that if I can get it towed to the garage, I should be able to back it up the short driveway's incline, at least up to the lip at the edge of the garage. If it won't roll over that, I can just jack it up and put some boards under the wheels to get them above the lip. I should have a lot more freedom to take things apart and do other tests once I'm in the garage.

I'll get it towed down there tomorrow, and see about getting it running properly on Saturday or Sunday. At the very least I hope to narrow down which cylinder isn't working properly. I'll get some gas, too. :) And new plugs.

Although if anyone has simple things to try in the parking lot, I'm willing to give them a go.

Thanks again!

-- Joe

[Spittybug]

Wait until dark, slide the rubber boots up the spark plug wire (if you can, else you'll need a jumper wire), run the car at higher rpm and look down the spark plug wells to see if any sparking is going on. If so, you've found your problem - micro cracks in insulator arcing to the well wall. A failing coil can have these symptoms too. Do you have access to a spare?

[jangell]

Of course it started raining, but I'll do that test in the garage, which is not only dark but has no electricity (or water, or bathroom -- it's a pretty basic garage, but makes up for it by having two autoparts stores and some fast food a few hundred feet away).

I don't know how normal this is, but when I was pulling the #6 and #5 plugs off with the engine running, I got tiny zaps when the wire got too close to the intake manifold. It's not clear to me if the wire should be insulated enough that that shouldn't happen, or if these are high enough voltage that this is normal. I didn't notice any sparks, but it was bright out and I didn't look too closely.

I don't have access to a spare coil, but plugs and coil aren't too expensive, and I imagine a new coil won't be hard to find locally.

Thanks!

-- Joe

[jangell]

I managed to get the car to the garage today. I just went out early enough in the morning that I wouldn't have to worry about holding too many people up. While I went a bit slow up hills, I made it without incident -- I was even able to drive it into the garage, over the 3" lip (I measured, and attached a picture).

During the trip, if I put the pedal down to the floor the car would clearly miss and it there would be popping sounds coming from the exhaust. Google tells me this popping is unburned gas detonating in the exhaust. When I took my foot off the gas a little the RPMs would go up slightly (say, from 2000 to 2100 or 2200) and the popping would go away.

I attempted to find which cylinder wasn't working, but I couldn't figure it out by pulling spark plug wires while the car was running, or by using a multimeter with a tach feature (the RPM went up when I removed the wire, according to the tach -- I'm guessing it didn't know how to read it properly). I replaced all six plugs (they're cheap, so why not) and the coil (as the old Bosch was reading a bit low on the ohm meter). This had no effect. Since I replaced the plugs, I didn't so Owen's test to see if the plug ceramic was cracked.

The way I'm testing it is putting the car in drive, holding down the brake and revving the engine. RPMs max at 1500 and the engine makes the "missing" sound. I'll be happy to record the sound if it would help anyone with diagnosing the problem.

I'm not sure what to test next. I'm thinking if replacing the remaining injectors, if I though that would help.

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I tries to take some pictures of the distributor cap so that I could avoid removing it, but that failed. I gather I need to take it off to inspect it?

Any other thoughts about what I should test?

Thanks!

-- Joe

[Spittybug]

Replacing the spark plugs with the "right" ones isn't exactly cheap. You did go with the recommended Bosch ones, right? There are countless stories of other plugs not performing well in our cars.

You are correct about the popping in the exhaust. A severe lack of power and the fact that you have oily plugs and the popping is what continues to make me believe you have an ignition, not fueling problem. Do you have a timing light? I'd be interested in seeing if your timing is advancing as you rev the engine. Is plausible that your mechanical advance isn't working right. What is your static advance?

We haven't ruled out distributor/rotor problems either. Your'e going to need to pop it off and check for cracks very carefully. Scorch marks too. How does the rotor look?

****edit.... you HAVE confirmed that your plug wires haven't been mixed up, right? The firing order is correct? 1,6,3,5,2,4 That would CERTAINLY give you such symptoms.

[jangell]

Replacing the spark plugs with the "right" ones isn't exactly cheap. You did go with the recommended Bosch ones, right? There are countless stories of other plugs not performing well in our cars.

...no... <looks down sheepishly> I just got whatever they had at NAPA next door, which happened to be the same plugs I was using before. I hadn't heard of issues with non-Bosch spark plugs before. I guess there's a part number for the "right" ones here somewhere?

Here's the thing, though -- the car has been running fine for a year now with these plugs. As such, I'd have expected new plugs of the same type to work. Still, if I'm using the "wrong" plugs ($18 for all six), then replacing them with Bosch is something I can do.


You are correct about the popping in the exhaust. A severe lack of power and the fact that you have oily plugs and the popping is what continues to make me believe you have an ignition, not fueling problem.

I admit that I was grasping at straws when I suggested replacing the rest of the fuel injectors. The idea of unexploded fuel in the exhaust also implied to me that there must be an ignition issue of some kind.


Do you have a timing light? I'd be interested in seeing if your timing is advancing as you rev the engine.

I do. I can check the timing either tomorrow morning (my wife needs the other car for most of the day, so I'm not sure I'll make it), or else on Tuesday morning.


Is plausible that your mechanical advance isn't working right. What is your static advance?

We're starting to hit the limits of my knowledge here; a friend helped me set up the timing when we did the top-of-the-engine rebuild, so I'm a bit fuzzy on this. I know OF those terms, but I'll have to look up how to check them.


We haven't ruled out distributor/rotor problems either. Your'e going to need to pop it off and check for cracks very carefully. Scorch marks too. How does the rotor look?

I'll see if I can get that off either tomorrow morning or Tuesday; as I recall, it's a PITA to get to (I finally took the engine cover off to get better access last time, although my friend was the one who did all the distributor cap work).


****edit.... you HAVE confirmed that your plug wires haven't been mixed up, right? The firing order is correct? 1,6,3,5,2,4 That would CERTAINLY give you such symptoms.

Recently, no. My only confirmation would be that the car was working perfectly fine until a few weeks ago, which implies to me that the order is correct. I mean, the wire length is such that I'm sure that they're plugged in correctly at the engine, but I'd need to verify that they are correct on the cap.

Thanks very much for the assistance!

-- Joe

[Ron]

I attempted to find which cylinder wasn't working, but I couldn't figure it out by pulling spark plug wires while the car was running, or by using a multimeter with a tach feature (the RPM went up when I removed the wire This is a red flag for being cross wired. I'd double check them anyway. (If one fires at the wrong time (cylinder), it can mess up "things" for another cylinder...
(One automatically means two ;-)

RE cylinder power test:
Every time you pull a wire, you should hear the engine start missing (unless it was already dead etc). The engine may not shake or sound rough, but you should hear at least a subtle drop in RPM (or see a drop on the gauge). Slowing the RPM down by putting it in gear or temporarily adjusting it up can help detection by accentuating the differences. Just have it steady as you can before you start pulling.

[Bitsyncmaster]

Don't forget to pull the idle motor connector after the engine has warmed up to do that spark plug wire pull test.

[David T]

...no... <looks down sheepishly> I just got whatever they had at NAPA next door, which happened to be the same plugs I was using before. I hadn't heard of issues with non-Bosch spark plugs before. I guess there's a part number for the "right" ones here somewhere?

Here's the thing, though -- the car has been running fine for a year now with these plugs. As such, I'd have expected new plugs of the same type to work. Still, if I'm using the "wrong" plugs ($18 for all six), then replacing them with Bosch is something I can do.



I admit that I was grasping at straws when I suggested replacing the rest of the fuel injectors. The idea of unexploded fuel in the exhaust also implied to me that there must be an ignition issue of some kind.



I do. I can check the timing either tomorrow morning (my wife needs the other car for most of the day, so I'm not sure I'll make it), or else on Tuesday morning.



We're starting to hit the limits of my knowledge here; a friend helped me set up the timing when we did the top-of-the-engine rebuild, so I'm a bit fuzzy on this. I know OF those terms, but I'll have to look up how to check them.



I'll see if I can get that off either tomorrow morning or Tuesday; as I recall, it's a PITA to get to (I finally took the engine cover off to get better access last time, although my friend was the one who did all the distributor cap work).



Recently, no. My only confirmation would be that the car was working perfectly fine until a few weeks ago, which implies to me that the order is correct. I mean, the wire length is such that I'm sure that they're plugged in correctly at the engine, but I'd need to verify that they are correct on the cap.

Thanks very much for the assistance!

-- Joe

You did that? On one car I had a similar problem, rough running and no power, it was one of the valve adjusters had loosened up and backed itself out and was laying inside. Do you hear a loud ticking under a valve cover? BTW, the PRV-6 seems to be very particular about it's spark plugs. Even though you use what should work as a X-Ref, it does not. And don't go with the platinum ones either. Another thing that can all of a sudden make things very rich, a stuck plunger in the fuel distributor.
David Teitelbaum

[jangell]

This is a red flag for being cross wired. I'd double check them anyway. (If one fires at the wrong time (cylinder), it can mess up "things" for another cylinder...
(One automatically means two ;-)

The fact that it was working until very recently makes me think that the wires are in the right order already, but I'll check to be sure, once I figure out how to actually look there without taking the mixture unit and intake manifold out.


RE cylinder power test:
Every time you pull a wire, you should have hear the engine start missing (unless it was already dead etc). The engine may not shake or sound rough, but you should hear at least a subtle drop in RPM (or see a drop on the gauge). Slowing the RPM down by putting it in gear or temporarily adjusting it up can help detection by accentuating the differences. Just have it steady as you can before you start pulling.

I actually did do this yesterday for 1, 2, 3 and 6. I did hear a drops on 1, 2 and 3, but there was no drop when I pulled 6. That's what led me to start replacing spark plugs (starting with 6, which didn't help anyway). I didn't do it for 4 and 5 because of how hard they are to get to without moving things like the idle air motor out of the way, but that doesn't mean I won't be able to do it.

I can give it a try on Tuesday (I can't make it to the garage today) before I check the cap, rotor, and which wires are going from the cap to the plugs.

Thanks!

-- Joe

[jangell]

Don't forget to pull the idle motor connector after the engine has warmed up to do that spark plug wire pull test.

Thanks. I should clarify that I was doing the "pull the wire" test while the car was still warming up. Does it only make sense to do this test after it has warmed up?

-- Joe

[Bitsyncmaster]

Thanks. I should clarify that I was doing the "pull the wire" test while the car was still warming up. Does it only make sense to do this test after it has warmed up?

-- Joe

You can do it while it warms up but with the idle speed motor disconnected you idle will slowly be increasing RPMs.

[jangell]

You did that?

To clarify: A friend of mine who works as a classic car mechanic for a living helped me with the re-assembly. I disassembled the top of the engine myself (down to removing the cylinder heads), but waited for him to help me put it back together. The heads were resurfaced, Ed Uding's cams were installed and DPI's SPEC I exhaust replaced the one I basically had to cut out of the car. We wound up doing a few other things while we were in there, like the transmission flanges, adjustable lower rear link arms, and a high-torque starter. My friend is the one who did the distributor and the valve adjustment, although the latter seems rather straight-forward to me (I did a lot of research on it as I assumed I would be doing that myself).


On one car I had a similar problem, rough running and no power, it was one of the valve adjusters had loosened up and backed itself out and was laying inside. Do you hear a loud ticking under a valve cover?

I did not notice any ticking noises from the valves, but I'll check again on Tuesday morning to be sure.


BTW, the PRV-6 seems to be very particular about it's spark plugs. Even though you use what should work as a X-Ref, it does not. And don't go with the platinum ones either.

Ok; it looks like the correct ones are Bosch HR6DS, right?


Another thing that can all of a sudden make things very rich, a stuck plunger in the fuel distributor.

I did try to remove the fuel distributor from the mixture unit when I did the engine overhaul, but found that the hardware was rusted in place. I was going to wait for my EFI conversion before trying to separate them.

I didn't notice it acting light it was stuck when I tested the fuel injectors by jumping the RPM relay and pushing the deflector plate down; it seemed to move smoothly enough, and the plate is closed at idle.

Thanks again!

-- Joe

[jangell]

I didn't get quite as much time to work on the car as I'd hoped today. And I think I screwed up both of the tests I actually did:

- I didn't hear any ticking sounds coming from the valves, so I don't think any have come loose. Unfortunately, this is from memory -- I forgot to put my head near the valve covers, so this is from my memory of the engine running. I'll have to listen again to be sure.

- The distributor timing appears to be dead on at 13 degrees. I did the test as per the workshop manual, which meant that I just turned the car on and had it idling at ~760 RPM with the timing light clipped onto #1's wire. Of course, I forgot to unplug the vacuum advance line (which for some reason wasn't in the two-step process in the Workshop Manual at M:01:02, although I may have simply missed it), so I'm guessing this reading is meaningless? I also did not let the car warm up first; it wasn't clear to me if this was required, and I didn't want to have to wait for it to cool down before I could work on it again.

I took pictures just to make sure I was reading everything correctly. They are of the timing light lighting up the mark on the pulley, a digital tach showing 760 RPM, and the car's tach showing about the same thing.
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I wasn't able to check the cap and rotor yet, because they're a PITA to get to. I took off the engine cover for better access, and unbolted the the mixture unit and W pipe so that I could shift them to get enough of a view of the distributor to make sure the wires on the cap are going to the right cylinders, but I didn't have time to finish that today. Annoyingly, I snapped one of the bolts that holds the mixture unit in place, and both of the bolts that hold the throttle spool to the side of the manifold were loose for some reason, with one of them snapping (or already snapped) when I tried removing it. Guess I'm taking the manifold off to pull out the broken pieces...

I'm hoping to get to the garage again on Thursday morning so I can check the cap and rotor, likely after I redo the timing test with the vacuum advanced disconnected from the distributor and after I listen for any tapping valves.

Thanks again!

-- Joe

[Spittybug]

If your micro switch at the throttle is functional, then it will have cut the vacuum to your distributor and your 13* is accurate. If the switch wasn't working, you'd have seen >23* I would guess. What I would have like to have seen is you rev the engine and confirm that the timing advanced! For that you SHOULD disconnect the vacuum advance so that it doesn't interfere with making sure that any advance is purely centrifugal. I'm theorizing this because if for some reason you aren't advancing as the RPMs go up, the spark comes late in the stroke and you are basically igniting the charge the piston is nearing the end of its throw rather than closer to TDC. If too much unburned charge leaves the cylinder, that's when you can get the popping in the exhaust.

[jangell]

Ah, I see. Ok, I'll put a few things back together and test that on Thursday morning. Thanks!

-- Joe

[Ron]

If your micro switch at the throttle is functional, then it will have cut the vacuum to your distributor and your 13* is accurate. If the switch wasn't working, you'd have seen >23* I would guess. What I would have like to have seen is you rev the engine and confirm that the timing advanced! For that you SHOULD disconnect the vacuum advance so that it doesn't interfere with making sure that any advance is purely centrifugal. I'm theorizing this because if for some reason you aren't advancing as the RPMs go up, the spark comes late in the stroke and you are basically igniting the charge the piston is nearing the end of its throw rather than closer to TDC. If too much unburned charge leaves the cylinder, that's when you can get the popping in the exhaust.Since it was cold, the thermal vacuum switch should be directing the vacuum to the WUR/CPR, so the switch would have no effect. IE the vacuum advance should have been disabled (but not for long). Good thing is that the setting is probably correct.

===========

P.S. If the RPM drops when pulling each wire, there is no need to check the cap and rotor (or if the wires are in the correct order ;-), they are doing their job.
If you are going to tear it down that far, you might as well change them both while you are in there...

[jangell]

Didn't manage to test the distributor today, unfortunately: I put back the bits I'd started removing the other day (mostly the W pipe and a fuel injector), and tried to start the car. It cranks fine, and would fire for a fraction of a second (sounded like up to three cylinders had fired before it just went back to cranking), and then it would just crank and crank. If I paused for 10 or 15 seconds it would fire once or twice and then go back to cranking.

I confirmed spark with a timing light, and I'm pretty sure I had fuel as I could smell it (I didn't pull any lines to confirm, but the fact that if I let the car sit for a bit before cranking would result in the car catching very briefly implies to me that I have fuel). I tried putting the CPR plug on the cold start valve, but it still wouldn't start. I pulled the cold start valve and put it in a jar, cranked the engine, and the jar was dry. I tested the cold start valve with a PowerProbe by applying 12v to one pin and ground to the other with the RPM relay jumped; again, nothing, no matter which pin I put 12v to. I didn't feel a solenoid kick when I applied power, but I'm not sure if the valve is strong enough to feel it.

I'm thinking that either the cold start valve is dead, or it's plugged and not operable. I suppose I'll order another one (and a cap and rotor, while I'm at it) -- unless anyone knows how to clean it and get it running again? This is most annoying, since I want to do EFI this fall, and I don't want to replace a part that I'm not going to use in a few months.

I tried to use a multimeter to test the harness connection to the CSV, but I was unable to get a reading with my multimeter. Some searches suggest that it is very difficult to get a reading from it for some reason. At the moment I'm assuming my thermotime switch is good, and that it's the valve that's bad.

I've attached a few (admittedly poor quality) pictures of the CSV's outlet. It looks 'dirty', but I don't know if that's how it's supposed to look. While the hole in the center is clear, it could be plugged up inside the housing.

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Again, thanks everyone for your help. I'm going to clean the tank and replace the fuel pump on Sunday, put in the Bosch plugs I ordered and probably check out the cap and rotor, since I can't actually start the car right now.

-- Joe

[lazabby]

You might check the wiring (plug) going to the CSV. I had a situation once where one of the wires in the plug was not seating properly so it wasn't making the connection.

[jangell]

I don't think ti's the connector on the harness. I should mention that this is a new harness (about a year old). Still, I should have tested it.

This morning I did do a few more tests suggested by Dave Swingle, since it's pretty uncommon for these to fail. Here's the list in case anyone else needs it:


1 – take the cold start valve off the engine.
2 – plug the grey plug from the warmup regulator onto the cold start valve. Put the cold start valve in a cup or jar.
3 – Pull the RPM relay. Jumper the brown wire on that socket to the Yellow-red wire AND the white-purple wire (the fan fail jumper is good for this if you have one). This will turn on the fuel pump AND hotwire the cold start valve at the same time.
4 – See if this makes the Cold Start valve spray. If so, it is not bad and you are chasing other problems. If it does not spray:
4A – Take the line off the cold start valve and turn the fuel pump on again. If no fuel comes out of that line, the pump isn’t running and you are chasing other issues. If fuel comes out of that line you probably do have a bad cold start valve.

ALSO - disconnect the cold start valve and measure the contacts on the valve with an ohm meter. If you read just about anything but infinity it’s good. Should be under 200 ohms.

ALSO – see if you can start and run the car on brake cleaner sprayed into the intake. If it will run on this, the entire ignition is good.

ALSO - take off the air cleaner. Have an assistant try to start the car. While cranking press the air flap with your finger. This will put more gas in the engine. If it runs like this you probably have the CO set way too lean to run.

I found the following:
- Using the CPR's grey connector on the CSV had no effect.
- Jumping the RPM relay to run the fuel pump and CSV had no effect.
- Taking off the CSV's fuel line sprayed fuel everywhere (what with it being under pressure)
- Jumping the RPM relay to run the pump with the CVS's fuel line disconnected sprayed more fuel everywhere (I didn't have a jar with me to collect the fuel).
- I got 400 ohms from the pins on the CSV's connector.

I'm thinking that the CSV is plugged up, but I have no idea how I'd clean it. I also don't know if I should feel the valve click open/closed when I apply voltage to the pins; when I try it, I don't feel anything like I do with the idle speed motor. Of course, the idle speed motor is a much larger unit.

-- Joe

[Bitsyncmaster]

My CSV reads 4.01 ohms. You may have just read the meter wrong but 400 ohms would not work the CSV. It takes a few amps to operate the CSV.

[DMCMW Dave]

My CSV reads 4.01 ohms. You may have just read the meter wrong but 400 ohms would not work the CSV. It takes a few amps to operate the CSV.

Or it is really bad.

[jangell]

I think you're both right: First, there's clearly no fuel passing through the CSV, so if it's not electrically bad then it's plugged.

Secondly, I probably read the multimeter wrong. misunderstanding the ranges and how to read them (you'd think I'd know how to do this by now). I happened to take the CSV home, and used a second (different brand) multimeter to test it, and got 5 ohm (after checking the docs to make sure I'm using it correctly).

At this point, I'm leaning towards not only the CSV being bad, but at least some of the five cleaned injectors are probably toast as well (It was worth a shot cleaning them, but David T did say they were the worst he'd ever seen), and although it seems to be working fine I wouldn't be surprised if there was some kind of damage to the fuel distributor as well. Rather than spend $500-$1000 on K-Jet parts just to replace them with EFI parts this fall, I think I'm going to move ahead with my EFI conversion. I know that trying to fix a problem by installing another entire system in its place isn't necessarily the wisest thing to do, especially if my problem isn't actual fuel related, and then I'm be fixing two things at once. But I'm sure everything will go great and I'll have no problems at all. :) I'll start up an EFI thread when I get closer to getting this going.

Still, I have a couple more tests to try, and maybe if I whack the CSV hard enough it will unclog and let me check out the mechanical advance tomorrow.

Thanks again everyone!

-- Joe

[jangell]

Another update:

I whacked the CSV against the floor a few times to see if I could unstick it, but no go. I did discover how much gas would be sprayed around the engine bay if you run the fuel pump when you've forgotten to tighten down the banjo bolt on the CSV, though.

I followed Dave Swingle's advice and started the car by pushing the air deflector plate down while cranking the starter. I didn't have an assistant, to crank, but I was able to work around this due to a relay I'd installed in the engine compartment to resolve a low-voltage starting issue many years ago (it's basically service bulletin ST-05-2/82, which I thought I had but actually didn't; this mode serves the same purpose). I plugged a momentary push button from Advance Auto into it in place of the relay, which allowed me to crank the engine while pushing down the deflector plate.

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The car started without too much trouble, although it was a little tricky to keep it running. I found that if it wouldn't start while I was holding the plate down a little, that releasing it and trying to start it, and then trying again with the plate down a bit would start it. If I released the plate the car would stall after a few seconds, although on my last attempt (after revving it a fair bit while checking the timing) it actually did stay running. At this point I noticed the plate remained slightly opened, never actually closing all the way while the car managed to stay running. I'm not sure if that's normal, or if it's supposed to be completely closed (it is completely closed when the car is off). It ran a bit rough, however; certainly not as smooth as when the CSV is working.

It took me a few tries to juggle pushing the button, holding down the deflector plate, pulling the throttle arm to rev the engine and grabbing the timing light to actually check the mechanical advance (with the distributor vacuum disconnected). It looks like it's working -- I don't know the RPMs (I had a tach hooked up but forgot to actually look at it), but the red dot on the pulley moved to the left (counterclockwise) quite a bit. If I had to throw a number out there I'd say it was at 40 or 50 degrees from 0. I have not put the Bosh plugs in yet, although I did get them; I'm still using the NKG TR5's.


I also tried cleaning the tank out more thoroughly so that I could install the new pump/sender combo. It was clear that this was necessary once I had the baffle out. New pictures show that under the pump and near the back of the tank were pretty dirty. My main problem is that I simply cannot reacy back that far -- my arm won't quite fit in the pump's hole enough to get my elbow in and reach all the way back. I'm thinking of picking up a squeegee or sponge-on-a-stick or something and trying again next weekend. Hopefully the acetone won't dissolve it too badly...

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This picture shows a pinhole leak in the plastic cap of the old fuel pump. I'm guessing this is how water was getting onto the top of the pump and rusting everything. I bet there's a small hole through the rust to the tank itself, too.

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Thanks again!

-- Joe

[Bitsyncmaster]

That pump and fuel hose is a mess. Glad your changing it out. That hose should have a rubber cover on it to protect it. It sure sound like your mixture is to lean.

[jangell]

I forgot to mention a couple of things:

- While playing with the throttle, I heard a few "popping" noises. They seemed to come from the air deflector plate or the air mixture unit, not the exhaust. They were similar to the noises that I thought I had heard from the exhaust when I drove it to the garage. It may have just been the plate banging against the top of the mixture unit as it closed, but I'm not sure. It wasn't conclusive enough for me to know what was going on.

- I could hear a hissing noise coming from the engine near the firewall. I was unable to localize it, and it's not clear to me if it's always been there or if it's new. Since I installed the new cams and exhaust I'd sometimes hear a similar whooshing air noise while driving (I think it was when I took my foot off the gas quickly, but I can't recall at the moment), although I just thought it was a side effect of those new components. AFAIK there are no vacuum leaks, or at least there weren't when I tested a year ago while trying to track down idle problems (wound up being a bent throttle arm that was keeping the throttles slightly open during idle, and thus made it impossible to get the RPMs down; I went so far as to do a poor-mans smoke test using a cardboard box, a fog machine and a fish tank pump, which actually did work surprisingly well). I haven't checked recently, though.

-- Joe

[jangell]

That pump and fuel hose is a mess. Glad your changing it out. That hose should have a rubber cover on it to protect it.

There was some kind of rubber sheathing on the hose -- the part outside the cover, I mean -- but it basically crumbled in my hands (what was left of it, anyway).


It sure sound like your mixture is to lean.

I'll take a look at that once I get the new fuel pump in. If I can get the car to stay running I can try to make it more rich, although at this point it might just wait until I do the EFI conversion.

Thanks!

-- Joe

[DMC5180]

You should not have to hold down on the air plate and the the throttle. Cranking the engine with the throttle partially open should automatically cause the air plate to open. at the very least once you have the engine running the air plate should be open slightly due to air flow. This is what regulates the fuel as air volume enters the engine.

The CSV does not do anything while the engine is running. I don't see how it would have any effect on it running better. Note: You did reinstall it I hope. It would be a massive air leak otherwise. Make sure the gasket is not torn either.

As for the tank cleaning, wrap an old wash cloth on stick or something and wet with acetone too wipe out what you can't reach.

[jangell]

You should not have to hold down on the air plate and the the throttle.

Ah, sorry; what I meant was I was holding down the air plate a bit while cranking the engine. Once it started, I had to switch between holding the air plate to pulling on the throttle arm. If I released the air plate, the car would stall (except for that last time, after I'd revved the engine). While I had the throttle open I could use the timing light to check the mechanical advance.


Cranking the engine with the throttle partially open should automatically cause the air plate to open. at the very least once you have the engine running the air plate should be open slightly due to air flow. This is what regulates the fuel as air volume enters the engine.

That's interesting; my attempts to start the car from the cabin while slightly pushing down the gas pedal failed when I tried it a few days ago. I did know that opening the throttles causes the air plate to move down and actuate the fuel distributor, but I didn't know that you should be able to start the car with the throttle slightly open. I wasn't sure if the idle switch not being depressed would interfere with starting.


The CSV does not do anything while the engine is running. I don't see how it would have any effect on it running better.

That should have occurred to me, what with it being called the "cold start valve". Not sure why I thought it had to do with the idle system; probably just because of the idle speed motor being near it.


Note: you did reinstall it I hope, It would be a massive air leak otherwise. Make sure the gasket is not torn either.

:) I did, mostly to ensure that the fuel line was hooked up, but I also screwed it down into its pipe to avoid any leaks. The gasket looked like it was OK.

As for the tank cleaning, wrap an old wash cloth on stick or something and wet with acetone too wipe out what you can't reach.[/QUOTE]


Cool; I'll hunt down a suitable stick for next weekend.

Thanks!

-- Joe

[Spittybug]

:dunno: Perplexing.

Still too many variables in play. If we could rule out the fuel injectors.........can you borrow some?


I heard a few "popping" noises. They seemed to come from the air deflector plate or the air mixture unit, not the exhaust. This has me wondering about valve timing..


Since I installed the new cams and exhaust I'd sometimes hear a similar whooshing air noise while driving Clue?

[jangell]

Still too many variables in play. If we could rule out the fuel injectors.........can you borrow some?

I thought about that too, but I don't know any other DeLorean owners in the area. I think my only real option is to buy a new set.


(re: popping) This has me wondering about valve timing..

We (my friend who knew what he was doing and I) were pretty careful when we set up the timing chains last year, although that doesn't necessarily mean we did it correctly. But the car did seem to run fine until a few weeks ago, and I'd never heard that popping sound prior to this. I'm not sure how the timing would change on its own; the chain would have to slip a tooth or something, right?

I don't suppose there's an easy way to test the valve timing without removing the timing cover or valve covers, is there? Although if I'm doing EFI, the driver's side valve cover will be easier to get to without all that K-Jet stuff on it.


(re: wooshing sound) Clue?

I'm not sure. I noticed an occasional wooshing noise from the engine bay while driving since I put the new cams/exhaust in a year ago, but that's not something you can narrow down from the cabin.

But this constant sound from the center-rear ("rear" being more towards the front of the car) of the engine bay, I'm not sure. I didn't notice it before, but maybe that's just because I have the air box off now (first time I removed it since doing the top-of-the-engine rebuild). It may have just been the air being sucked past the slightly-opened air deflector plate. Of course, making any change to how open the plate is affects how the car is running, which may be mask the source of the sound elsewhere. I have an automotive stethoscope thing that I've never used; I don't know if it would help tracking down this problem in free air. I guess it wouldn't hurt to try, once I put the new fuel pump in and can try starting it up again. I could play with the mixture a bit too and see if that does anything.

-- Joe