Warm Start Issue - Resting Fuel Pressure Drops to 0 after 5 minutes

[Nuclearbacon]

Hello Everyone! Thank you for reading.

My car usually cold starts no problem, and was warm starting perfectly. Back in 2010, the previous owner purchased a new fuel pump, and accumulator kit from DMC in Garden Grove (love those guys) and the cars been great until about a month ago. I'd drive it somewhere, park for an hour. When I'd get in, turn the key, the car would instantly fire up and die. Then I'd run the starter and run the starter and run the starter like the car had no spark. Checked my grounds. Found a loose ground under the ballast resisters and one on the frame rail. Still issues after tightening. Cleaned up the connections on the ballast resisters. Finally decided to get in and check the fuel pressure. I'm losing fuel pressure after the car is turned off.

After hooking up a fuel pressure gauge, I found the rest pressure drops to 0 from about 3.75 bar within 4 minutes. The shop that is helping me specializes in the Bosch K Jetronic system which is really cool. It's nice to have someone looking over my shoulder who seems to know the system pretty well as I'm just learning it as I go along.

In September of 2010 the car had a new fuel pump and accumulator installed along with a whole o-ring fuel kit sold from DMC garden grove. Everything I'm reading says my accumulator is no good, but it should be new-ish still right? Could my accumulator be bad after only 4-5 years and less than 7000 miles?

I also found this: http://support.delorean.com/KB/a61/hot-start-issues.aspx

Looking at the my previous invoice I mentioned above, I wanted to make sure I didn't have an older style fuel pump as mentioned in the website. I believe my fuel pump is a newer style. The shop thinks that the fuel pressure is being leaked into the cylinders causing a flooding issue. or instead of it leaking into the cylinders, could it be losing pressure through the o-ring the site above mentions at the end? The shop seems to think the system pressure regulator o-ring is the culprit. They also want to pull my injectors to inspect.

What would you do? What do you think it is?

Thank you!

:)

[hmcelraft]

So, why don't you trust the mechanics? Specialists should be able to test it readily - especially if they have the gauges and all the accessories to test the system? The O ring sounds like as good a place to start as any. Fuel pressure dropping very fast as in your case is a major leak-down. They will be able to determine the fault quickly I suspect. The O ring is cheaper than the fuel accumulator and much less labor cost. If you have the mechanic isolate the accumulator to test it you may as well replace it and get your labor money's worth. If by chance the replaced accumulator you mention was NOS (new old stock and 30 years old) it could have failed after little use because of poor storage over the years, etc.

Don't forget there is a backflow valve at the fuel pump that can go bad also. The newer style fuel pump just not as often (or rarely).

[Nuclearbacon]

I do trust them! I was just curious since I have the weekend before I can place the order, I'd just ask!

[sdg3205]

The areas of warm start issues:

1. Accumulator - remove rear hose and check it holds 20 in Hg vacuum

2. PPR - 3 possible o rings can be faulty. Inspect.

3. CSV - prime system and inspect for leak

4. Injectors - prime system and inspect for leaks

5. Pump check valve - pinch send hose after priming and see if rest pressure holds.

[BigChapMatt]

I was having the same hot start issue, after replacing everything. I found out it was the check valve within the brand new fuel pump/sender unit had failed. So when the car is shut down, you lose all your fuel pressure back into the tank.
I proved this by using the fuel pressure gauge on the engine and then pinching the fuel line near the pump and the pressure remained high once the engine was shut down. The easy solution was to put an after market in line check valve just after the fuel pump.

[Nuclearbacon]

Thank you for the replies!

Update!

Got ahold of DMC in LA, asked about my fuel pump to see if it was the older style mentioned above with the questionable valve, and my series was one of them. So I
purchased my own K Jetronic Fuel Pressure Test Kit. Got it this morning and went out, hooked it up and recreated my drop in fuel pressure after reaching operating temperature almost exactly 4 minutes to 0psi. Repressured the system, turned the car off, went to the front of the car and pinched off the supply line from the fuel pump and still had a drop in pressure. Seems my check valve isn't the issue.

Time to start at the beginning for MYSELF. The shop said they tested my accumulator. I am going to grab a vacuum gauge tomorrow and get under the car and see if I have the 20"Hg with my own two eyes. If I do, I continue onwards.

SO nice to have the fuel pressure kit. I highly recommend it, as other have recommended it to me. I'm also ordering Dave's solid state relay as a gift to my car when I figure out the starting issue.

Onto Vacuum testing!

[Bitsyncmaster]

Replacing the PPR o-ring is a 5 min job, so that's what I always do first.

I have seen a few NOS accumulators fail with very little time in use.

[Josh]

I had a rest pressure issue. Turned out to be the elbow that screws into the bottom of the fuel filter!

[Nuclearbacon]

Defective vacuum gauge. Sonofa.....

[sdg3205]

Defective vacuum gauge. Sonofa.....

?


Sent from my iPhone using Tapatalk

[Nuclearbacon]

?


Sent from my iPhone using Tapatalk

The Vacuum gauge I ordered and received was defective. It was... frozen in time.

[Nuclearbacon]

When I moved to the beach from my inland 2.5 car garage, I gave up the convenience of having my jack and jackstands within reaching distance of my drivers door. It's now a 30 minute hassle of carting my jack and stands all the way across cobblestone apartment complex to where the car is parked.

I tell you this because if I would have had my jack/stands handy, before even hitting the forum, I would have gone under the car and seen THIS:

http://i528.photobucket.com/albums/dd329/nuclearbacon2008/DeLorean%2010588/IMG_2345.jpg (http://s528.photobucket.com/user/nuclearbacon2008/media/DeLorean%2010588/IMG_2345.jpg.html)

http://i528.photobucket.com/albums/dd329/nuclearbacon2008/DeLorean%2010588/IMG_2339.jpg (http://s528.photobucket.com/user/nuclearbacon2008/media/DeLorean%2010588/IMG_2339.jpg.html)

Because of failing light (thanks a lot, sun) and doing it right after work, I had to peek, take photos, drop the car back down, clean up and jump on my PC to see the carnage.

Holy-fuel-return-line! It's splitting! Doesn't look like its leaking (yet) and the other hose looks like it has wet road slime or something. When I touched the "wet looking" line and smelled it, it did not smell like fuel.

http://i528.photobucket.com/albums/dd329/nuclearbacon2008/DeLorean%2010588/IMG_2338.jpg (http://s528.photobucket.com/user/nuclearbacon2008/media/DeLorean%2010588/IMG_2338.jpg.html)


Full album of 8 photos (http://s528.photobucket.com/user/nuc...Lorean%2010588)

I guess I'm ordering a few fuel lines this evening! could I be losing holding pressure from that ugly rubber return line? Could it be the sticky goopy line? I want to take all of that out of there and replace everything, including the accumulator since I'm there, but! I still haven't hooked it up to vacuum.

I'd like to take car down to my folks place, where my dad has all the stuff I'd need to get that accumulator out and tested. I just wish I could get the parts to put on, on Saturday... and now I'm thinking out loud.

[Nuclearbacon]

33110

Just noticed these hose/worm clamps on John's reference photo...

Should I have these clamps in place??? Because I don't.

If I'm losing holding pressure because I'm mysteriously missing hose clamps.... dude :thumbdown:

[DMCMW Dave]

33110

Just noticed these hose/worm clamps on John's reference photo...

Should I have these clamps in place??? Because I don't.

:

The factory install, and some aftermarket (notably Grady's orange Aeroquip hoses) do not use hose clamps on the pressure line. They were a pressure fit Teflon hose. At this point most of the aftermarket solutions are using a rubber hose which needs the clamps. Yours happens to look original.

It was common a decade ago to replace the accumulator and not replace the hoses.

[Rich]

When I touched the "wet looking" line and smelled it, it did not smell like fuel.

http://i528.photobucket.com/albums/dd329/nuclearbacon2008/DeLorean%2010588/IMG_2338.jpg (http://s528.photobucket.com/user/nuclearbacon2008/media/DeLorean%2010588/IMG_2338.jpg.html)

...... could I be losing holding pressure from that ugly rubber return line? Could it be the sticky goopy line? .

Great to have some pics to get things in order there. Nothing to add to Dave's notes about what normal hoses might look like nowadays.

First, your photobucket link did not work at this end, so will work with one you posted.

Second, only two of the 4 lines in the feed-return system are pressurized and only those 2 pressurized lines could possibly be a hose-degradation-related cause for your rest pressure drop problem, among the other causes of that symptom. Am counting the feed line from pump to accumulator and fm accumulator to engine as separate lines.

For the rest pressure issue do not worry about the unpressurized return line (engine back to tank) or the accumulator bleed/overflow line (single line by itself on thin end of accumulator, also connects to tank, maybe together with fuel return).

Degraded fuel lines that do not leak fuel and are not pressurized are not great but are not your main issue. The worst indication from the pics is that some of your main feed lines may be just as bad someplace else - no way to see from these pics.

Are you ever detecting any fuel odor? If not then it points more to the accumulator than the hoses. When the accum. blows it safely leaks fuel back to the tank and you won't smell that. Here we leave aside rest pressure issues in the K-Jet itself or in the fuel pump chk valve.

So what to do next?

Try pulling the bleed/overflow line off of the back of the accumulator (left connection in photos), attaching your vacuum tester there and seeing if the accumulator is leaking at full vacuum. You were already planning to do that?

If it won't hold vacuum then plan to replace it and to also replace any degraded lines, pressurized or not, while you're at it. If it holds vacuum then the leak is either is happening at the accum. only under higher pressure (vacuum is only 1 bar and the system runs at ~5 bar) or the leak is elsewhere, not in accumulator. Fuel line replacement is in your future in any case, it seems. Urgently or otherwise.

[Nuclearbacon]

Working link for album of 8 photos. (http://s528.photobucket.com/user/nuclearbacon2008/library/DeLorean%2010588)

[Nuclearbacon]

I will get vacuum on that line as soon as I can :) Thank you for the response!

[Nuclearbacon]

Finally!

I pulled the rear line off of the accumulator and fuel poured out of the line and the accumulator.

at this point I was pretty sure I knew what was wrong :facepalm:, but I put vacuum on the accumulator anyway and I could barely hold 10 inches of vacuum.

4 year old accumulator DOA. New one is on its way.

----------------------

Thank you everyone for fighting through something that I should have systematically gone through. I just didn't want to think my semi-new accumulator gave it up. :) I'm learning thanks to you all.

I am very appreciative. I'll let everyone know when it's in and functioning like it SHOULD be with awesome rest pressure.

Enjoy this awesome photo of the amazing garage I was able to use last evening.

33247

[GR8SCOTT]

Sweet pic!

[GR8SCOTT]

3325233253h

If anyone ever needs an inline fuel check valve, US Plastics Corp sells a great one. I have one installed in my car.

33254

[DMC5180]

Finally!

I pulled the rear line off of the accumulator and fuel poured out of the line and the accumulator.

at this point I was pretty sure I knew what was wrong :facepalm:, but I put vacuum on the accumulator anyway and I could barely hold 10 inches of vacuum.

Having fuel pour out of the spring side chamber via the 1/4" hose barb is normal because it is tied to the return side of the fuel system circuit via a T fitting. Nothing prevents system return fuel from running into the spring chamber. In fact the action of the accumulator bleeding off system pressure draws fuel into the spring chamber.

Your vacuum test is what verifies a good or bad accumulator. When you get your new accumulator, perform the same vacuum Proof test too it and share the results please.

[Nuclearbacon]

perform the same vacuum Proof test too it and share the results please.

Roger Wilco

When I put my vacuum gauge and could not even get 10", I knew it was bad. I will post findings of the new accumulator!

[Nuclearbacon]

As previously requested, the vacuum difference between the failing accumulator and a new one out of the box. (http://youtu.be/51DSH7Jv2Wg)

This weekend was the weekend!!! Got the old accumulator out and the new (smaller) one installed. The newer one was much smaller! Check out the difference!

Old:

http://i528.photobucket.com/albums/dd329/nuclearbacon2008/DeLorean%2010588/IMG_2344.jpg (http://s528.photobucket.com/user/nuclearbacon2008/media/DeLorean%2010588/IMG_2344.jpg.html)

New:

http://i528.photobucket.com/albums/dd329/nuclearbacon2008/DeLorean%2010588/IMG_2462.jpg (http://s528.photobucket.com/user/nuclearbacon2008/media/DeLorean%2010588/IMG_2462.jpg.html)

mmmm tasty new fuel lines.
oh and my rest pressure?? Do I hold 1.7 bar for 10 minutes?

....
.......
..............How about 2.7 bar after 1.5 HOURS!!!! Hows THAT for some rest pressure!

As soon as my accumulator was installed, I looked over and saw my fuel filter with the slightest weep. I took the nut off, and I couldn't sever the fuel line from the filter. I saw numerous examples of how the flange sits on the L piece going into the bottom of the fuel filter, but it didn't want to budge. So, cleaned up the connection as best I could, used a small piece (one wrap around) of yellow teflon tape ,re-tightened and the leak was eliminated. I will be replacing the fuel filter in the next few months, so that will be adressed.

I also installed my SS coolant tank, but that was easy peasy lemon squeezy.

I believe my rest pressure issues are solved! Wahoo! :rock_on:

[PJ Grady Inc.]

I'm going to ad my two cents here "Nuclear Bacon" (Is that your real name;)) but please don't take this as offensive. I'm glad you solved your problem but I don't understand why people sell/install the smaller (4 cylinder intended) fuel accumulator when the correct one is still available? Although it's cheaper and gets the job done it doesn't fit properly (as is obvious in your picture TYVM!) and can't possibly hold rest pressure as long as the correct larger unit.

Until it's unavailable the larger one is the only one I'll carry even though it obviously puts me at a price disadvantage to the other vendors. To me it's a sign that the owner services his car with the cheapest parts available and makes me take a harder look at other previously serviced areas of the car for incorrect parts. I'll admit it seems to "get er done" but it isn't the best way.

To each his own but "that's how I roll" as Jeremy VanBemmelen used to tell me. I sure do miss that young man!
Rob



As previously requested, the vacuum difference between the failing accumulator and a new one out of the box. (http://youtu.be/51DSH7Jv2Wg)

This weekend was the weekend!!! Got the old accumulator out and the new (smaller) one installed. The newer one was much smaller! Check out the difference!

Old:

http://i528.photobucket.com/albums/dd329/nuclearbacon2008/DeLorean%2010588/IMG_2344.jpg (http://s528.photobucket.com/user/nuclearbacon2008/media/DeLorean%2010588/IMG_2344.jpg.html)

New:

http://i528.photobucket.com/albums/dd329/nuclearbacon2008/DeLorean%2010588/IMG_2462.jpg (http://s528.photobucket.com/user/nuclearbacon2008/media/DeLorean%2010588/IMG_2462.jpg.html)

mmmm tasty new fuel lines.
oh and my rest pressure?? Do I hold 1.7 bar for 10 minutes?

....
.......
..............How about 2.7 bar after 1.5 HOURS!!!! Hows THAT for some rest pressure!

As soon as my accumulator was installed, I looked over and saw my fuel filter with the slightest weep. I took the nut off, and I couldn't sever the fuel line from the filter. I saw numerous examples of how the flange sits on the L piece going into the bottom of the fuel filter, but it didn't want to budge. So, cleaned up the connection as best I could, used a small piece (one wrap around) of yellow teflon tape ,re-tightened and the leak was eliminated. I will be replacing the fuel filter in the next few months, so that will be adressed.

I also installed my SS coolant tank, but that was easy peasy lemon squeezy.

I believe my rest pressure issues are solved! Wahoo! :rock_on:

[Nuclearbacon]

Hey Rob! No offense taken! I called DeLorean, asked for a new accumulator and they sent me a new accumulator. I figured if I ordered it from DeLorean, it's correct.

You're right, it doesn't fit exactly, but as from my last test, I hold 2 hours of rest pressure @ 2.7bar. That sounds good to me but boy that seed of doubt is planted!

Do you feel this is a crappy part? Do you feel I got screwed in some way? Should I be concerned? Will it fail because of its smaller size? Eek!

[PJ Grady Inc.]

Absolutely not. It's a Bosch part that apparently holds pressure under normal conditions long enough to do the job. You got what you paid for. The larger six cylinder sized accumulator holds pressure longer than it needs to so it's more of an insurance policy that the extra size may last longer as time goes on and the diaphragm starts to leak. I won't be able to say for sure until they start failing. When the cars were newer the NOS units did not start failing with frequency until the ninties so they usually lasted 10 to 15 years. With the outsoucing of so many parts these days there's no telling how long either style of these new Bosch accumulators will last. The larger unit is still made in Germany however so they should last about the same as the originals baring other differences. I could ask my WD if the smaller ones are still German but anyone who sells them could chime in here? I don't really like the accommodations you have to make for the smaller one to fit but I have installed a customer supplied unit and would not refuse to do so in the future.

That being said I like to consider myself a "non-anal perfectionist" who will make compromises for the sake of expediency where warranted. I just won't start selling them until the "factory correct " part becomes unavailable or outrageously expensive whichever comes first. There's no reason to feel bad because although it may look hokey to me when installed you're not exactly parading your accumulator around in public, it gets the job done, and you saved yourself $50- give or take. Now does that make you feel better or worse? I'm trying to be PC here!!!!! BTW I guess your first name really is "Nuclear" or do you just prefer anonymity? :)
Rob


Hey Rob! No offense taken! I called DeLorean, asked for a new accumulator and they sent me a new accumulator. I figured if I ordered it from DeLorean, it's correct.

You're right, it doesn't fit exactly, but as from my last test, I hold 2 hours of rest pressure @ 2.7bar. That sounds good to me but boy that seed of doubt is planted!

Do you feel this is a crappy part? Do you feel I got screwed in some way? Should I be concerned? Will it fail because of its smaller size? Eek!

[Nuclearbacon]

Hey Rob! I'm Luigi :) (My name is at the bottom)

I paid $134.95 for my fuel accumulator from DeLorean. (http://store.delorean.com/p-6548-fuel-accumulator-new.aspx)

I'm pretty sure the part was stamped Germany, I'll check my pics.

Intrigue! Possible deceit! All over a Fuel Accumulator! I can see the movie promos now...

[PJ Grady Inc.]

Man I think I'm working too hard Luigi if I couldn't see your name for the trees! It's 10:40 and I'm still finishing last minute ad copy for the next "Delorean world."
I need to get a life but I'm actually having fun over here...how pathetic. Eyes starting to blur now :)




Hey Rob! I'm Luigi :) (My name is at the bottom)

I paid $134.95 for my fuel accumulator from DeLorean. (http://store.delorean.com/p-6548-fuel-accumulator-new.aspx)

I'm pretty sure the part was stamped Germany, I'll check my pics.

Intrigue! Possible deceit! All over a Fuel Accumulator! I can see the movie promos now...

[DMC-81]

3325233253h

If anyone ever needs an inline fuel check valve, US Plastics Corp sells a great one. I have one installed in my car.

33254

Hi there,

I am getting ready to install this same(or similar) check valve in the feed line coming out of the same new style DMC-TX fuel pump. Question: does anyone know which one is the feed line?

Thanks,
Dana

[sdg3205]

Hi there,

I am getting ready to install this same(or similar) check valve in the feed line coming out of the same new style DMC-TX fuel pump. Question: does anyone know which one is the feed line?

Thanks,
Dana

Have you installed the new pump? It should come with a check valve. If not, it certainly comes with instructions for installations. Either way, when looking at the hard lines, the send line is the inside line, closest to the tank.

[DMC-81]

Thanks Dave! Very helpful.

The fuel pump was installed when I bought the car in 2013, so I don't have instructions. I am retrofitting the check valve after the fact, as the pump didn't come with one at that time. Now that my car is up and running again, I am installing the valve, a new fuel accumulator and filter.

Based on what I read about these last 2 tasks, I am prepared to learn new swear words. :swear1:

:smile:

Dana

[cpistocco]

What's nice about my car is how the oem braided fuel line (coming off the accumulator) falls right into the automatic gear shift linkage. Nice engineering. :)

[Jonathan]

What's nice about my car is how the oem braided fuel line (coming off the accumulator) falls right into the automatic gear shift linkage. Nice engineering. :)

Could just be the way you have it routed (or from the guy who worked on the car before you got it)?

This area on my car is no masterpiece, but maybe a well placed zip-tie would help? (see pic)

40820

But yes, engineering is no nice in a few spots, eh?

[cpistocco]

Could just be the way you have it routed (or from the guy who worked on the car before you got it)?

This area on my car is no masterpiece, but maybe a well placed zip-tie would help? (see pic)

40820

But yes, engineering is no nice in a few spots, eh?

Yes...your ziptie is holding the braided hose up. Without that it would be dangling into the shift linkage. I will try something similar on mine. My only fear is that the ziptie may cut into the hose. Very lame engineering back in 1981.....

[cpistocco]

Yes...your ziptie is holding the braided hose up. Without that it would be dangling into the shift linkage. I will try something similar on mine. My only fear is that the ziptie may cut into the hose. Very lame engineering back in 1981.....

Another nice touch (speaking of the fuel system) is the way they routed the fuel filter and lines within 2 inches of the exhaust pipe.

[DMC-81]

Yes...your ziptie is holding the braided hose up. Without that it would be dangling into the shift linkage. I will try something similar on mine. My only fear is that the ziptie may cut into the hose. Very lame engineering back in 1981.....

I'm doing this zip tie placement right now. Basically the new rubber hose needs to be routed the same way as Jonathan's original (braided) hose to prevent it from kinking. This morning, I zip tied the hose to the hard line for the pipe that goes to the filter. I didn't tighten the tie too much to avoid it cutting into the hose. Really, it just needs to hold the hose away from the linkage.

This accumulator was a bear of a job..... one that I attempted several times (see my posts above) with shorty wrenches. No go :rant:. I tried to have a mechanic do it as well....no go :what_the:. I thought that I'd have to have help at the upcoming local tech day. But, I think I have it conquered now, all thanks to a 17mm crow's foot. :woot:

I'll post my one handed, blind work, in a tissue box sized area when I'm done.

[cpistocco]

I'm doing this zip tie placement right now. Basically the new rubber hose needs to be routed the same way as Jonathan's original (braided) hose to prevent it from kinking. This morning, I zip tied the hose to the hard line for the pipe that goes to the filter. I didn't tighten the tie too much to avoid it cutting into the hose. Really, it just needs to hold the hose away from the linkage.

This accumulator was a bear of a job..... one that I attempted several times (see my posts above) with shorty wrenches. No go :rant:. I tried to have a mechanic do it as well....no go :what_the:. I thought that I'd have to have help at the upcoming local tech day. But, I think I have it conquered now, all thanks to a 17mm crow's foot. :woot:

I'll post my one handed, blind work, in a tissue box sized area when I'm done.

I swear that they (the engineers) went out of their way to make things as difficult as possible!! I cut a small section of old rubber hose and placed it over the braided fuel hose so that the zip tie could not cut into it. Then, I later removed the zip tie, and, instead, used a "s" hook, hanging from the inlet where the steel fuel line emerges... Maybe I should take a pic... Worked great!

[PJ Grady Inc.]

What's nice about my car is how the oem braided fuel line (coming off the accumulator) falls right into the automatic gear shift linkage. Nice engineering. :)

You're missing a double C clip and tie-wrap that is used to lock it out of harm's way to the fuel hard line. We can blame the PO I guess?
Rob

[PJ Grady Inc.]

Could just be the way you have it routed (or from the guy who worked on the car before you got it)?

This area on my car is no masterpiece, but maybe a well placed zip-tie would help? (see pic)

40820

But yes, engineering is no nice in a few spots, eh?

These lines are way overdue for replacement. The accumulator looks old too based on that drop of waxed up fuel danging from the rib/bulge area. Has it been changed as the lines did not leave the factory routed that way?

[DMC-81]

Here are some pics of my fuel accumulator adventure. I would rather tear into the VOD again before doing this job one more time....

My starting point was an original FA and lines. I was having hot start issues, and the problem was getting worse. Plus the outer rubber layer of the hoses has disintegrated off exposing the fiber braid layer....

40878

Here is the new hardware. I got the original size Bosch accumulator from Summit Racing. Then gates barricade fuel hoses and fuel injection clamps. Plus a DMC pad.....

40879

Here is the part number of the new accumulator, which is the same as the old one....
40880

Here are the tools I used for the fuel accumulator job.
- a 17 mm crow's foot on a socket wrench to remove the fuel filter hard line fitting
- a short length of copper pipe to extend the socket wrench for leverage
- a 17 mm long combination wrench to hold the bigger integrated nut on the accumulator while removing and reinstalling the hard line fitting
- a 19 mm long combination wrench for removing and reinstalling the flexible hose fitting (i did this with the accumulator removed from the car)
- a 7 mm socket and combination wrenches to tighten the hose clamps
- safety goggles
- a piece of wooden strapping to hold the accumulator up to the hard line fitting while I mated them.
- a piece of coat hanger wire to hold the flexible hose square on the accumulator side barb fitting while I installed the clamp. I tried to install the clamp with the accumulator out of the car, but the hose was kinking and it was in the way of tightening the fittings.
As mentioned, the shorty wrenches did not work for me, either the 17mm nor the 19 mm.

40881

I used a 17mm crow's foot on a socket extended by a piece of copper pipe for leverage. Then I secured the accumulator from rotating with a 17mm long wrench on the integrated nut on the other fitting. SUCCESS! Finally!!...

40882

After the hard fitting was removed, and the bracket, I was able to lower the unit out of the frame opening.....

40883

I cut the nylon fuel line to get the unit out further. I used an oil change pan to catch the fuel. When I removed the return line from the back of the accumulator, fuel started siphoning out of the 3/4 full tank. I had to use compressed air in the line to break the siphon action....

40884

Here is the old accumulator. Notice the bent fitting for the hard line. This is partially why I couldn't get the shorty wrench to work. The nut on the hard line fitting was too close to the other fitting.

40885

I removed the fiber layer, and used a razor blade to carefully score the nylon line. Then I used small needle nose pliers to split the line away from the fitting. Luckily, I didn't score the brass barbs. Phew!!....

40886

Here is the new fuel accumulator completely installed and lines/hoses tightened. After a few pump primes with the key, the car started right up. And no leaks!! I broke the double C plastic hose clip, so I'll have to buy that and add it later.

40887

I know that this job was done hundreds or thousands of times before, but I thought I'd share my experience for someone who has a similar problem.

Cheers,

[DMC5180]

Great write up.

I'll add 1 alternate tip: it's easier to remove the hard line nut from 90 deg fitting, remove the 4 bolts from the FA body clamp and rotate the FA down about the hardline. Work it back and forth till the line separates from the fitting. Then the flexible lines can be cut as required. Transfer the 90 fitting to the new FA and maintain fitting orientation. Reinstall as required.


Dennis

[cpistocco]

Great write up.

I'll add 1 alternate tip: it's easier to remove the hard line nut from 90 deg fitting, remove the 4 bolts from the FA body clamp and rotate the FA down about the hardline. Work it back and forth till the line separates from the fitting. Then the flexible lines can be cut as required. Transfer the 90 fitting to the new FA and maintain fitting orientation. Reinstall as required.


Dennis

Yes... It is easier to access the fitting before the 90 degree elbow. The access hole is oblong, so it makes it easier to swing a wrench in that direction.

[cpistocco]

You're missing a double C clip and tie-wrap that is used to lock it out of harm's way to the fuel hard line. We can blame the PO I guess?
Rob

Thanks Rob.... You are right....again ! :)

[DMC-81]

Great write up.

I'll add 1 alternate tip: it's easier to remove the hard line nut from 90 deg fitting, remove the 4 bolts from the FA body clamp and rotate the FA down about the hardline. Work it back and forth till the line separates from the fitting. Then the flexible lines can be cut as required. Transfer the 90 fitting to the new FA and maintain fitting orientation. Reinstall as required.


Dennis

Thanks Dennis. I see that that was the method in one set of procedures that I read, and one that I tried. All 3 fittings were super tight on mine, and I was at risk of kinking the hard line. The only solution for me was turning the socket into a small breaker bar while holding the FA.

I agree that that would be easier.

[Jonathan]

These lines are way overdue for replacement. The accumulator looks old too based on that drop of waxed up fuel danging from the rib/bulge area. Has it been changed as the lines did not leave the factory routed that way?

Thanks for mentioning that, Rob.

It got me to look back at my notes, some pictures of previous parts orders, and the parts diagram for this area.

A brief history...

Got my car in 2007. Had a bunch of problems and didn't drive it much at all for the 1st couple years. Hot start might have been an issue since (my) day one, but might not have known since I didn't go anywhere in the car.
I see in my notes I bought the accumulator kit from DMCX in early 2011.
I had since started doing most all the work on the car myself, but decided to take the accumulator job to a local shop instead. Looks like the accumulator got replaced in the summer of 2011.
Now, since I likely didn't know where exactly the hoses that came with the kit were meant to go... and the mechanic wouldn't have taken the initiative to figure it out himself... it looks like I have those same hoses Dana shows in his pictures still in a parts box.

That's a good thing.

I also have a few other fuel line related odds and ends waiting for me to stop procrastinating and just get installed.

When that accumulator went in, the hardline just before the filter developed a pinhole leak. I suspect it was from the mechanic twisting it a little too hard not realizing the other end wasn't supported well enough. At the time, we cut out that leaking portion (1-2 inches approximately) and spliced in a short piece of fuel line hose with clamps on both ends. It has been fine ever since, but in the meantime, knowing I'll get to it eventually, I bought the replacement hose with fittings that goes all the way from the connection on the filter (I have a new one of those too), routed along and through the frame at an opening near the trans, to the accumulator. This ends up being that centre connection on the accumulator with the right angled fitting.

I'll need to gather all my parts and confirm I have everything I need. Tools as well, as Dana listed out. I will likely get under the car and assess how badly I think it will be to get the two connections loose from the hoses, the ends of the hoses that aren't connected to the accumulator that is. I suspect they are probably going to be pretty rusty and a PITA to loosen up. That might have been the reason it wasn't done earlier. As mentioned, the space to work in is the size of a tissue box and if you get a little overzealous and twist a hardline the wrong way, you've likely done more harm than good. I may just end up doing the fuel hose replacement from accumulator to filter depending on how ugly it looks when I get under there.

Question for you, Rob, on that routing and C-clips and whatnot you mentioned:

Do you have a photo of how these hoses and clips are supposed to be routed? Like how they were meant to be from the factory, originally? Thanks.

Oh, and that drip you mentioned... it could be fuel, you're right. I had thought it was ATF though as I believe there to be a small leak going along the shift cable as the little grommet seal isn't holding perfectly. I have not gone under for a look in a while, but it looked very similar as recently as last May when I had the car up in the air on a tech day hoist.

[DMC-81]

After a test drive today with a few stops, I can say that the hot start issues are solved!

:elmo1: :woot:

I'll touch up 2 areas on the frame in the FA box, and then I can get back to the interior.

[DMC5180]

Thanks Dennis. I see that that was the method in one set of procedures that I read, and one that I tried. All 3 fittings were super tight on mine, and I was at risk of kinking the hard line. The only solution for me was turning the socket into a small breaker bar while holding the FA.

I agree that that would be easier.

When I replaced my FA several years ago during a local tech session. I had the same feeling that the line would twist. Fortunately, I had the assistance of long time DMC mechanic Don Steger at the event. He assured me that it would come loose. He reached up and supported the fitting (pivot point) , then grabbed the FA at the opposite end giving it a sharp pull downward. I was surprised that it moved. A couple twists back and forth and it was separated.


Dennis

[cpistocco]

It would appear that the new accumulator cured my hot start issue too..... But now I seem to have picked up a new problem: My fuel pump is howling like a banshee. I never could hear the pump run before the accumulator change. Could it be the increase in fuel pressure? I don't like the sound of it at all.

[hmcelraft]

It would appear that the new accumulator cured my hot start issue too..... But now I seem to have picked up a new problem: My fuel pump is howling like a banshee. I never could hear the pump run before the accumulator change. Could it be the increase in fuel pressure? I don't like the sound of it at all.

Does the pump make the noise when things are cold (all of the time) or hot (after running an hour or so)?

[cpistocco]

Does the pump make the noise when things are cold (all of the time) or hot (after running an hour or so)?

Thanks for the reply...
I will check.... But it never made any noise (hot or cold) before the new accumulator.
Classic Delorean story...One step forward....two steps back.

[cpistocco]

BTW....
How does a "cold" humming noise differ from a "warm" humming noise?

[hmcelraft]

BTW....
How does a "cold" humming noise differ from a "warm" humming noise?

Well, what I was suggesting - in my experience - good fuel pumps may make noise when Hot - a lot of noise. A loud hum like a deep siren noise of sorts. No noise when cold except for the regular low hum of the motor.

Over the years I have experienced the noise in three different DeLoreans. Changing fuel pumps never helped. It seemed to be made because of "over heating" fuel (hot enough to cause the fuel pump to make the awful noise). I addressed that as the issue because, when the noise occurred, if I put in cold fuel at a gas stop, the noise was gone when I started up to leave and did not return for quite some time, if I kept driving. The Hot fuel appeared to be caused by the coolant lines laying against the fuel tank where the coolant lines pass through the frame at the tank. I put an insulating hose around the coolant pipes from behind without dropping the tank - just dropping the back of the cover some. The noise was gone for several years until this spring.

I found the Loud noise occurred again this spring when the fuel tank pressurized - a lot -because the fuel "rollover valve" was stuck closed. I think there was a heat built up in the fuel because the tank expanded and pushed against the coolant lines as the pressure rose. The noise hasn't returned since I fixed that. I am concerned that my homemade heat shield may have been damaged because of the pressure and I may experience some heat issues again when I drive this summer.

I believe the hot fuel pump noise can also be caused by the usual bad electrical connections causing the pump to get hot. Those should be checked regularly. The connections at the pump, at the gang plug in the window washer bottle compartment, the ground through the rollover switch, the RPM relay connections and fuses, etc.

[Bitsyncmaster]

I instrumented my gas tank and fuel return line and found the return line temp was always a few degrees warmer than the gas in the tank. So the gas in the tank would continue to increase in temperature the longer the engine was running. My fuel pump would buzz when the gas went above 120 deg. F in the tank. Now the coolant lines running beside the tank may add to the problem but I think most of the heat comes from the engine heated fuel returned to the tank.

I have not had any pump buzz since installing my return line cooler I installed years back.

[cpistocco]

Thank You both for the info..... I cant believe that there are so many quirks to this car......were any real engineers involved in its development? :) But we still haven't figured out what the accumulator replacement has to do with the noise.

[hmcelraft]

Thank You both for the info..... I cant believe that there are so many quirks to this car......were any real engineers involved in its development? :) But we still haven't figured out what the accumulator replacement has to do with the noise.

My guess is - the leaking accumulator allowed cooler fuel to by-pass a trip through the hot engine compartment. Now all excess fuel passes through the engine compartment and heats up on it's return to the fuel tank. The hot fuel issue is just another product of the short life of the original DMC. There are so many CIS systems out there but, from my observation, the DeLorean is the only car that has the fuel tank in an area that gets exposed to consistent heat from the engine by fuel passing through engine compartment and back to a fuel tank exposed to heat from the radiator. I also suspect that not all fuel pumps react to the heat the same way. The fuel pump on my current DeLorean has been in at least 20 years and it gets the hum, or roar, when it gets overly hot. Maybe a new (I mean newly manufactured, not NOS) would tolerate the heat much better. I believe also that electrical issues contribute to the DeLorean problems of the fuel pump - poor connections and grounds.

[PJ Grady Inc.]

I instrumented my gas tank and fuel return line and found the return line temp was always a few degrees warmer than the gas in the tank. So the gas in the tank would continue to increase in temperature the longer the engine was running. My fuel pump would buzz when the gas went above 120 deg. F in the tank. Now the coolant lines running beside the tank may add to the problem but I think most of the heat comes from the engine heated fuel returned to the tank.

I have not had any pump buzz since installing my return line cooler I installed years back.

That's very clever Dave but besides possibly affecting A/C temps aren't you worried about the chance of fire? Though it may seem remote the A/C accumulator is essentially behind (agreed it's to the inboard side) the R/F tire and the copper tubing could be easily pierced by road debris resulting in a massive fuel leak over the entire R/H flank of the car. Just wondering if you considered that? We'd hate to lose you in a giant fireball as it would be a modern day premature Viking funeral! Perhaps at least put shielding of some sort over it?
Rob

[PJ Grady Inc.]

Thank You both for the info..... I cant believe that there are so many quirks to this car......were any real engineers involved in its development? :) But we still haven't figured out what the accumulator replacement has to do with the noise.

Delorean employed many engineers both directly and indirectly not to mention the Bosch engineers that originally designed CIS. As they say the devil is in the details and the details were the devil in the breakneck pace to both design a car and build a factory to assemble it in a few years time. It had never been done that quickly before as Barrie Wills book will attest to.
Rob

[sdg3205]

That's very clever Dave but besides possibly affecting A/C temps aren't you worried about the chance of fire? Though it may seem remote the A/C accumulator is essentially behind (agreed it's to the inboard side) the R/F tire and the copper tubing could be easily pierced by road debris resulting in a massive fuel leak over the entire R/H flank of the car. Just wondering if you considered that? We'd hate to lose you in a giant fireball as it would be a modern day premature Viking funeral! Perhaps at least put shielding of some sort over it?
Rob

Is there such a thing as a fuel rad? Something similar to a transmission cooler? A small motorcycle rad would work too, but are they not used simply because of the fire concerns? Do they really add that much risk?

Something like this

http://uploads.tapatalk-cdn.com/20160331/e4f0873273d0269cd426f25f69181fc9.jpg

[Bitsyncmaster]

That's very clever Dave but besides possibly affecting A/C temps aren't you worried about the chance of fire? Though it may seem remote the A/C accumulator is essentially behind (agreed it's to the inboard side) the R/F tire and the copper tubing could be easily pierced by road debris resulting in a massive fuel leak over the entire R/H flank of the car. Just wondering if you considered that? We'd hate to lose you in a giant fireball as it would be a modern day premature Viking funeral! Perhaps at least put shielding of some sort over it?
Rob

Yes I considered the AC might not work as good but it does not seem to have effected the AC performance.

That copper tube is pretty heavy soft copper. I guess the chance of road debris hitting it is very remote and since is soft copper it probably would just dent it. There is some epoxy covering the ends to hold it tight onto the accumulator. There is no pressure in the return line so I feel it's pretty safe.

[David T]

There are fuel coolers that racers use to chill the fuel to make it denser but they are basically a big bottle filled with ice chips that has a small coil that the fuel runs through. Using the A/C to cool the fuel is not unusual. If you are worried about the copper getting damaged, just wrap a piece of sheet metal or plastic (probably a better choice) over it. Another source of heat is the coolant lines running alongside the bottom of the tank. The other thing that has been done is to hang a piece of rubber over the front of the fuel tank to keep the hot air from the radiator fans off of the tank and it deflects the air under the car. Once the pick-up hose gets hot it softens up and kinks or collapses under the vacuum from the fuel pump. When that happens the fuel pump starts "singing". It needs all of that fuel flow to lubricate and cool it. Without full flow it makes a lot of noise till it dies. Another "tip" is to put a spring inside the hose so it won't collapse. Once the pump starts getting loud it is damaged and will just get louder.

[DMC-81]

I remember a fuel cooler being one of the enhancements that Andre talked about on the 3 world tour cars. I wonder what their setup looks like?

[burch]

I remember a fuel cooler being one of the enhancements that Andre talked about on the 3 world tour cars. I wonder what their setup looks like?

I can't remember right off, but is that what the new vents on the front fenders of their cars were for?

[sdg3205]

I can't remember right off, but is that what the new vents on the front fenders of their cars were for?

That sounds familiar

[cpistocco]

That sounds familiar

How about taking the return fuel line, and adding a length of coiled line in an area where there is good air flow (yet protected from road debris). Wouldn't that act as a mini radiator? The fuel should be cooled to some extent.

[Jonathan]

In a perfect world, you would probably have the coolant running through that coil and then have it spiralled around a straight (and protected) fuel line. On our cars though, or any car really, there isn't an extra cooling loop that would have it's own heatsink and pumping ability. You could use the engine coolant on it's way back to the engine from the radiator, but the temperature of even the "cold" side would likely make matters worse rather than better with the fuel temperature.

If we have no add-on cooling loop, there could be a way to try and divert up some airflow to get at or around the fuel lines or tank. Maybe some sort of modest air scoop integrated into the fuel tank closing plate, that would let air rushing under the car up into a slight opening at the front of the plate, then down along the length of the tank, and out the back of a corresponding opening. You might be able to test an easy and simple version of doing this just by offsetting the location of the fuel tank closing plate by putting a certain thickness of washers on each bolt, between the plate and the bottom side of the frame where the bolts go. I'd have to look closer at how much the tank may rest right on the plate, to allow that air flow pathway, and maybe you reposition the pads or add a couple spaces to take the weight but still give you some cooling.

Just a thought anyway.

[cpistocco]

Thanks Guys.... You are all very generous with your time.

Two last questions.... Is there any way to determine how much resistance the pump is pushing against. I have an external check valve (and maybe a check valve on the pump). I am also unsure if the inside diameter of my fuel hoses (near the tank) is large enough. Again, the noise began with the new accumulator. Wouldn't that increase the pressure that the pump is fighting?

Also, should I check the voltage at the pump with the pump running or shut off?

[Bitsyncmaster]

Thanks Guys.... You are all very generous with your time.

Two last questions.... Is there any way to determine how much resistance the pump is pushing against. I have an external check valve (and maybe a check valve on the pump). I am also unsure if the inside diameter of my fuel hoses (near the tank) is large enough. Again, the noise began with the new accumulator. Wouldn't that increase the pressure that the pump is fighting?

Also, should I check the voltage at the pump with the pump running or shut off?

You want to check the voltage across the two pump terminals with the pump running. If your voltage reading is low, then you can check each pump terminal using the battery ground and start tracing back the circuits to find bad connections. I would guess you can check your pump efficiency by measuring how much return fuel you get. It should be a large amount of returned fuel with the engine at idle.

As far as pump buzz. I did have the spring inside my pump pickup hose and had Hervey's heat shield keeping radiator heat off the tank and still got the buzz. So buzz is not always caused by the pickup hose collapsing. I was considering making an electronic pump controller which would hold 75 PSI primary pressure. That would eliminate most of the heated return fuel into the tank. You still need the return line for the lambda (FV) return fuel.

[cpistocco]

You want to check the voltage across the two pump terminals with the pump running. If your voltage reading is low, then you can check each pump terminal using the battery ground and start tracing back the circuits to find bad connections. I would guess you can check your pump efficiency by measuring how much return fuel you get. It should be a large amount of returned fuel with the engine at idle.

As far as pump buzz. I did have the spring inside my pump pickup hose and had Hervey's heat shield keeping radiator heat off the tank and still got the buzz. So buzz is not always caused by the pickup hose collapsing. I was considering making an electronic pump controller which would hold 75 PSI primary pressure. That would eliminate most of the heated return fuel into the tank. You still need the return line for the lambda (FV) return fuel.

Thank you for your input Bitsyncmaster