Mystery Cold Start Problem-- Who can solve this mystery? Grab some pop corn..

[Beachdrifter]

Hi All,

This is for all those who love a good mystery. Because I sure as heck am at the end of my rope on this one.

The last time my car started normally was on December 14th. It started just fine, no hesitation at all. All I did was move it in and out of the garage as I was prepping to remove my seats to recover the skins.

I lifted the car on all fours, and for the next two days, I worked on my seats, and reinstalled them. I also decided, "what the heck, let me replace the 30 y/o ignition coil while I'm at it" , so I bought a new Bosch replacement "00027" and popped it right in.

So I am all excited, and go to start the car. For 1-2 seconds after I turn the ignition and engine starts, it sounds just fine, as it reaches idle range ~800 rpm, it stumbles and dies.

I tried a couple of times, and same thing happened repeatedly. At this point I naturally assumed, it was something I did wrong with the ignition coil. So I swapped it back with the good known old one and tried again. To my surprise, SAME thing happened repeatedly. Again, car ignites and sounds strong for the 1-2 secs, then stumbles and dies.

One thing I did notice is by trying to press the gas pedal during the start process, the engine would not rev at all like it normally would. I could not get it to rev past 1200 rpm on the gas pedal. It would hesitate and just stall.

For the next few weeks, I tried the following:

1. Checked my starter resistor and connections. All were clean and good. --Did not affect start issue.

2. Checked the connections on the coil. All were clean and good.--Did not affect start issue.

3. Even tried jumping the coil directly to the battery post. --Did not affect start issue.

4. I swapped out the ignition relay in the engine bay with another one. --Did not affect start issue.

5. I replaced the CPR/WUR - --Did not affect start issue.

6. I checked the cold start valve by disconnecting it, at that point the engine would not even try to ignite, so I knew the cold start valve was working since I was getting at least the engine to start cold before it died.

7. I swapped my Idle ECUs, and Ignition ECUs -- Did not affect start issue.

8. I checked my Frequency Valve. It was buzzing and was getting correct Ohm reading across contacts 2-3ohms. -- Did not affect start issue.

9. I inspected my idle air valve, and it cycles as it should. -- Did not affect start issue.

10. As far as I know, all my vacuum lines are good, considering the car started just fine the time before and always drove well.

11. Replaced the battery with a new one, since mine was from 2006. -- Did not affect start issue.

12. The air pressure plate on the mixture unit is not stuck or binding. It holds pressure as it should and moves freely. So accumulator is doing its job. -- Did not affect
start issue.

13. A week before, I had put some Seafoam in my tank, so I drained the tank of most of the fuel and refilled with fresh fuel -- Did not affect start issue.

14. I took the fuel pump out, and looked inside for debris and such. None. I even replaced the fuel pump with a brand new one. -- Did not affect start issue.

15. I replaced the lambda relay. -- Did not affect start issue.

16. I replaced and tried several fuel pump relays. I even jumped the relay. -- Did not affect start issue.

17. Considering I have only driven my car like 5000 miles or less in the past 8 yrs, and have already replaced the fuel filter once, I don't think it is the problem.

18. When I spray some carb cleaner in the air inlet, it will start and idle a bit longer, like for 2 mins, but engine shakes bad and idles horribly, does not rev much at all if I pull the throttle spool.

19. I have already replaced my spark plugs, several yrs ago, but again, since I have only driven my car like 5000 miles in the 8 yrs I have had it, I don't assume it's a problem with plugs. The car started just fine the day before all this started. Also pulled a plug out to see if I had spark and I could see a small blue spark, so It looked good to me.

20. I've banged my Fuel distributor with a rubber mallet to see if something was stuck in there. -- Did not affect start issue.

21. I've checked all my fuses, 1 & 7 , especially,-- Did not affect my start issue.

22. I went exploring in the relay compartment and made sure all the wires were tight and good. -- Did not affect my start issue.

23. I plugged in and out all the bulkhead connectors. -- Did not affect my start issue.

24. My fuel distributor is from at least 2005 since I bought a rebuilt one at that time. I have all stainless steel lines.

25. My distributor , cap, and rotor is from at least 2005. Considering the low mileage < 5000, I doubt this was the issue.

26. When I connect a dwell meter, I am getting the nominal ~40 . (which is about 20 on the 8 cyl range)

27. I would like to check my fuel pressure, but considering I have a new pump, and air plate holds pressure like it should. I figure I am getting the correct fuel pressures.

=============

I am royally stumped. It just seems unreal that the car would go from perfect running, to the other extreme, not running. It starts but dies immediately. Has this happened to anyone? Maybe someone here can solve this mystery? I'm out of ideas. I will have time to check the car this coming weekend. Any thoughts are GREATLY appreciated. Thanks for reading my mystery novel.

Thanks!!

--Randy

[DMCMW Dave]

,

13. A week before, I had put some Seafoam in my tank, so I drained the tank of most of the fuel and refilled with fresh fuel -- Did not affect start issue.

----
17. Considering I have only driven my car like 5000 miles or less in the past 8 yrs, and have already replaced the fuel filter once, I don't think it is the problem.


The sea foam may have broken something loose in the system. This sounds kind of like a plugged fuel filter or injectors. (Cold start valve dumps a lot of gas in the engine, it starts and then runs out of gas). A quick test for that is take the line off the fuel distributor, run the pump, and see how much fuel comes out. If that looks good, the next thing I'd do would be an injector flow test (The injector-in-the-jars (beer bottles) test that you've probably seen on another thread today).

None of this relates to the coil, but it could relate to the Sea Foam that you just mentioned in passing. . .

[Spittybug]

I think Dave is on the right track. I'd lean towards fuel too. Electric problems are seldom as repeatable as yours seems to be.

[David T]

The sea foam may have broken something loose in the system. This sounds kind of like a plugged fuel filter or injectors. (Cold start valve dumps a lot of gas in the engine, it starts and then runs out of gas). A quick test for that is take the line off the fuel distributor, run the pump, and see how much fuel comes out. If that looks good, the next thing I'd do would be an injector flow test (The injector-in-the-jars (beer bottles) test that you've probably seen on another thread today).

None of this relates to the coil, but it could relate to the Sea Foam that you just mentioned in passing. . .

I know you said the frequency valve is buzzing but the symptom is what would happen if the frequency valve wasn't working. Also since you messed with the coil, it is nearby to the frequency valve. I agree it would seem like the motor is leaning out once it is off the cold start valve. Maybe the way to start would be to get a pressure gauge on the fuel system and check the duty cycle on the frequency valve. Maybe the frequency valve is working (buzzing) but plugged up because of the Seafoam?

[Beachdrifter]

The sea foam may have broken something loose in the system. This sounds kind of like a plugged fuel filter or injectors. (Cold start valve dumps a lot of gas in the engine, it starts and then runs out of gas). A quick test for that is take the line off the fuel distributor, run the pump, and see how much fuel comes out. If that looks good, the next thing I'd do would be an injector flow test (The injector-in-the-jars (beer bottles) test that you've probably seen on another thread today).

None of this relates to the coil, but it could relate to the Sea Foam that you just mentioned in passing. . .

Thank you all for your replies. I know this is a lengthy post, and I appreciate it.

I actually thought of the possibility of the Seafoam dislodging something somewhere and messing up the fuel system too, but was in denial. Up to that point, I never had used it and thought it would be a good preventative thing since I had seen some good reviews.

Now I have to buckle up and mess with the dreaded fuel system to see what's happening.

So,

1. I saw the How-To on the forum on testing the injector flow pattern, and will attempt to take them off this weekend and try it with the jars.

2. Dave S, you mentioned removing the line from the Fuel Dist. to see how much fuel was going to it.
a. Which particular line are you talking about? The one on the very top or the main input line?
b. Also, how much fuel flow would you consider acceptable from this line? I guess this test is meant to show if my fuel filter is clogged.
c. Lastly, if a fuel injector is clogged, do I soak it in Berryman's B12 to try to clear it up for like 24 hrs?

3. Dave T, thanks for the insight on the Freq Valve. I will consider that a possibility as well if the injector test is good. But I initially figured the valve was ok because when I was able to get the car to idle a bit longer by luck, my dwell readings seemed normal. But at this point, who knows I'm willing to look at anything and everything!

Thanks, I will try these two things to attempt to get to the bottom of this, And definitely report back. I hate seeing posts that people don't follow up on and leaves you wondering :).

--Randy

[DMCMW Dave]

2. Dave S, you mentioned removing the line from the Fuel Dist. to see how much fuel was going to it.
a. Which particular line are you talking about? The one on the very top or the main input line?
b. Also, how much fuel flow would you consider acceptable from this line? I guess this test is meant to show if my fuel filter is clogged.
c. Lastly, if a fuel injector is clogged, do I soak it in Berryman's B12 to try to clear it up for like 24 hrs?
--Randy

The line from the filter that connects on the back right of the fuel distributor. This is a handy one to remove and put over a bucket. Turn on the pump, the fuel flow should be pretty generous, over a gallon a minute. This will check the filter (and pump).

I've not had much success soaking injectors, but sometimes you can clear one by dribbling some B12 or even generic carb cleaner into the injector and then forcing it with a rubber tipped compressed air line. This is a lot more pressure than the injectors typically see. Unfortunately the injectors have tiny screens inside, and if plugged with something hard (rust particles for example) there is no way to back-flush it and get the bad stuff out.

[Beachdrifter]

Hi all,
So let me give you an update. Ding ding ding! Dave S, looks like you are on the path to finding this who-done-it.

I started by removing my injectors. Started the fuel pump by jumping the relay, and pressed on the air plate. To my surprise, only 2 injectors were spraying ;even with the plate all the way pressed in. At this point, I removed each injector , and jumped the pump. Without the injectors, fuel was flowing from all lines but at mostly a trickle flow. Not what I expected.

So at least I was getting some flow through the fuel distributor. At this point.was thinking it was only clogged fuel injectors,but then I decided to do the last test.

I then removed the line from the fuel filter, and placed it in a bottle. I jumped the pump, and instead of getting the gallon per min Dave S. said I should get, I was getting somewhat of a trickle flow in comparison. I was getting anxious just trying to get to a gallon.

So, now I know my problem is a fuel issue.

1. At this point I will leave the fuel distibutor alone, and will soak injectors to try to clean them the best I can. I don't think the injectors are the problem though.

2. Lastly, since the main line had low flow, I assume it is the source of my problem.

Is it possible my fuel filter is so gummed up inside that it is restricting the flow? It can't be the pump because I installed a new one during my other troubleshooting trials.

My car is driven probably a couple hundred miles a yr, and this would be a shock that the fuel filter would be clogged . Is this probable? Anything else to consider as at fault ?

My next step will be to replace the filter and see what happens.

Thanks so much for your help,

Randy

[DMCMW Dave]

Hi all,
--
Is it possible my fuel filter is so gummed up inside that it is restricting the flow? It can't be the pump because I installed a new one during my other troubleshooting trials.

My car is driven probably a couple hundred miles a yr, and this would be a shock that the fuel filter would be clogged . Is this probable? Anything else to consider as at fault ?

My next step will be to replace the filter and see what happens.

Thanks so much for your help,

Randy

Take the line off the inlet side of the filter and see how it flows there. You could have a kinked line at the pump or accumulator too.

[David T]

Take the line off the inlet side of the filter and see how it flows there. You could have a kinked line at the pump or accumulator too.

Is there any way you could have mixed up the lines at the fuel pump? if you did you would only get a trickle. Double-check you are going from the pump to the feed hose and the return line is dumping back into the tank.

[Bitsyncmaster]

I have seen a fuel filter completely blocked but do the test suggested (check flow input side).

[Beachdrifter]

Hi guys,

Thanks for the inputs.

So today, I went ahead and just took the whole fuel filter off.

I hooked a bottle to the filter input line, and started the pump. As I set a stop watch to 60 secs and did a countdown, I noticed the bottle was filling up a bit faster, but no where near the 1 gallon per minute rate I should be getting. After 60 seconds of letting the pump run, I saw I only got like a total of about 8-10 oz of fuel through.

As I inspected the fuel in the bottle, I noticed a few (about 4-5 pieces) of some small black round debris, maybe like 1/16th of an inch in diameter. When I grabbed one and tried to analyze it, it appeared to be some sort of small rubberish type of debris. I would have expected the fuel to be mostly clear , with the exception of VERY fine particles at this point, because what I saw in the bottle would not have made it through the suction screen of the fuel pump.

And just for the heck of it, I connected my garden hose to the fuel filter, and saw a nice steady stream come through, so no blockage there (will be using a new filter of course after this! ) :)

So something is definitely not right.

I now know something is blocking the fuel between the filter and fuel pump.

1. The fuel pump is brand new. Just installed a couple weeks ago thinking it was the culprit of all this. When I took it out to replace, I did not notice any unusual debris or clogged suction screen, so I assume the new pump should be good too.

2. In Sept 2013, I replaced my fuel accumulator because my old one had malfunctioned and stopped holding any pressure . I looked at it today for a kinked line, and didn't see any. The only thing that can explain the particles I see in the fuel is perhaps debris from the OLD accumulator that has clogged the fuel line?


Bottom line is, I am getting low flow out of the filter input line, and this is the problem of why the car was only turning on during initial start (with feed from cold start valve) and die soon after. The car was barely getting fuel through 2 of the 6 injectors.


I feel close to solving this issue. Any insights or similar experiences with this type of situation is appreciated!

Thanks ,

--Randy

[Bitsyncmaster]

Did you get the wires reversed on the new pump instal? Or the supply and return hoses reversed. You should be getting 100 PSI of pressure it the flow is that slow. You can try the flow test at the top of the pump but it sure sounds like it will be the same bad flow.

Can you get a voltage reading over the two pump terminals?

[Beachdrifter]

Did you get the wires reversed on the new pump instal? Or the supply and return hoses reversed. You should be getting 100 PSI of pressure it the flow is that slow. You can try the flow test at the top of the pump but it sure sounds like it will be the same bad flow.

Can you get a voltage reading over the two pump terminals?

Thanks Dave M. I confirmed that the pump is hooked up correctly.

However , when I did check the voltage at the pump, I get just over 9v. I'm not sure if that has always been the case even when the car was running before . But it seemed low to me. Could this be why the pump is giving a low discharge pressure ? Also, but battery is brand new.

Thanks.

[David T]

Thanks Dave M. I confirmed that the pump is hooked up correctly.

However , when I did check the voltage at the pump, I get just over 9v. I'm not sure if that has always been the case even when the car was running before . But it seemed low to me. Could this be why the pump is giving a low discharge pressure ? Also, but battery is brand new.

Thanks.

The small round black chunks are pieces of the diaphragm from the old accumulator. It does sound like something is plugged up. Now pull the discharge hose off the fuel pump and do another flow test.

[Bitsyncmaster]

Thanks Dave M. I confirmed that the pump is hooked up correctly.

However , when I did check the voltage at the pump, I get just over 9v. I'm not sure if that has always been the case even when the car was running before . But it seemed low to me. Could this be why the pump is giving a low discharge pressure ? Also, but battery is brand new.

Thanks.

Assuming your battery has 12 volts, getting 9 volts is on the low side. Check the fuse, RPM relay, pump connector connections. You can test if the ground side or hot side is bad by testing voltage on the (-) pump terminal to ground. The ground side drop is about 0.5 volts.

My car had two bad pump connections. One was a fuse terminal and the other was that two pin connector terminal near the pump.

[Beachdrifter]

Hi all,

Thanks for all your assistance . Here is an update.

So today i decided to reinspect the accumulator line, before attempting to test the fuel pressure directly from the pump.

As I inspected the accumulator line, ran my fingers along the braided hose. As I got near to the accumulator connection , I noticed the tube underneath the braid was not nice and round as it should be, but rather it felt as if the tube underneath the braid was broken. This reminded me of a bone broken and trying to pierce through the skin. As I moved the hose it kinked easily.

I believe this is affecting My fuel supply pressure which is affecting my starts. I don't remember my hose being like this when I replaced my accumulator back in Sept .

So the line is kinked and broken. I've attached pics and you can see the distortion on the line.

Looks like this can be the cause, thanks for your thoughts. What is the best way to replace this line?

Randy.

[NightFlyer]

What is the best way to replace this line?

Randy.

Sharp razor blade the old hose off the barb fittings and fuel injection hose clamp the replacement piece of hose on both ends.

[David T]

Sharp razor blade the old hose off the barb fittings and fuel injection hose clamp the replacement piece of hose on both ends.

As you inspect and test things you will find stuff. It may actually be contributing to, or even causing the problem. Obviously when you do find things wrong they have to be corrected but chances are you are not so lucky as to actually be fixing the cause. The again maybe you are lucky and this time you found it! This is how a little job becomes a big job. A large part of what usually needs to be done is to A: fix things that were neglected and B: fix things that were done incorrectly by a PO.

[Rich_NYS]

I just changed mine.....I had a bit of confusion over the ID of the hoses, but replacement was a fairly easy job.

[kings1527]

I'm curious to see if that's really the cause of your problem. From what I can see in the picture, it seems like a very small deformity to cause enough of a drop in pressure while starting. Keep us posted.

[jawn101]

Man, what is it with these hoses this month?

[kings1527]

Man, what is it with these hoses this month?

Seriously, Jon. One thing that I've found with under 9k cars produced, 6000 or so left, and arguably 2k or so on the road and running is that there's ALWAYS someone else going through the same trouble out there in the DeLorean world! Unbelievable!

I've dealt with my accumulator (and hose) problem but I'll post it in that hose thread.

[Beachdrifter]

Ding ding ding!!

We have a winner. Thanks all for your help through all this , as this has been my most difficult Delorean diagnosis, and real pain.

Dave S was correct. Upon closer inspection of the accumulator hose, I initially did not notice any kinks, UNTIL i actually ran my fingers and felt the line for any distortions; not just visual inspection. As I stated before, I felt a noticable distortion to the touch.

So I took a razor blade and cut the bugger off. To my surprise, the hose was twisted and kinked to the point where it did not return to it's normal state, thus preventing ANY real fuel flow through the line . No WONDER I was getting just dribbles. Once I cut the kinked section and jumped the pump, fuel flowed to the the approx rate of 1 GPM.

I have a new hose on order and looking forward to get the car started again. Wish I hadn't spent so much time checking everything else, but learned a lot about the car and fuel system from this experience.

Check out the photos, hope this doesn't happen to you!

-Randy

[jawn101]

Ding ding ding!!

We have a winner. Thanks all for your help through all this , as this has been my most difficult Delorean diagnosis, and real pain.

Dave S was correct. Upon closer inspection of the accumulator hose, I initially did not notice any kinks, UNTIL i actually ran my fingers and felt the line for any distortions; not just visual inspection. As I stated before, I felt a noticable distortion to the touch.

So I took a razor blade and cut the bugger off. To my surprise, the hose was twisted and kinked to the point where it did not return to it's normal state, thus preventing ANY real fuel flow through the line . No WONDER I was getting just dribbles. Once I cut the kinked section and jumped the pump, fuel flowed to the the approx rate of 1 GPM.

I have a new hose on order and looking forward to get the car started again. Wish I hadn't spent so much time checking everything else, but learned a lot about the car and fuel system from this experience.

Check out the photos, hope this doesn't happen to you!

-Randy

...Year of the Accumulator Hose.....

[Ryan S.]

Original hose? It doesn't look like mine.

[kings1527]

Awesome! I guess the exterior of the hose doesn't always tell the full story.

I just replaced that same line on my car with an 18" section of 1/4" ID fuel injection hose from Pep Boys for about $5 and it works great. Just make sure you have enough line coming off that nipple up in the hard line of the car so there isn't a sharp bend when you get everything in place. That happened to me with a hose I ordered that was about 14" or so.

This makes me want to replace my original hose going from the top of the fuel filter to the distributor.