#10715 rest pressure/thuds, accumulator

[jmrydholm]

Well, I went outside this evening after letting my DeLorean sit for about one day. It looks like my starting difficulty now decided to affect the car even when it's been off for many hours. I also still get that "thud-thud-thud" quite often. What do you think guys, dead accumulator? It's not the NOS one, as I have had it replaced at least one time before. This one has just sat for 2 years.

Is there any way to save a dead accumulator or should I just get a new one?

-John R.
#10715

Edit- it does eventually start- after I pump a great deal of gas into the system- and I ran it for a good 20 minutes to charge the battery back up from cranking it over and over again tonight.

[Bitsyncmaster]

Was your replacement accumulator NOS (new old stock). I think you meant to say "not original" in your post.

To test the accumulator would require you pressure test it at the outlet hose from the accumulator. Testing the pressure it should read greater than 100 PSI since you won't have the PPR holding 75 PSI. You could just block that outlet line and see if your thumping slows down to one or two an hour.

I would get the car up so you can crawl under it and look for any leaks first. Jumper the RPM relay to keep the pump running when your looking for leaks. It may be just a hose or leaky fitting on the accumulator or fuel filter.

With your quick rest pressure loss (many thumps very quickly) if it were just a leaky hose you should see gas easily.

If you don't see the gas then the fuel pump check valve or accumulator are the most likely failures if your PPR o-ring looks good. Also look at the fuel pump to be sure no leaks show up there.

[jmrydholm]

Hmm, I may have to take it in to have it checked out. I don't have much to raise it up that high. (Jackstands just let me work on the oil) I don't see any gasoline on the driveway, could it be a very small drip of a leak? Any kind of special tools I need to read the pressure with?

[David T]

Sounds like you now have TWO problems. A bad accumulator (or check valve or leaky PPR) which is affecting your hot restarts and a problem with the Cold Start Valve affecting your cold starts. NO, you cannot "repair" a bad accumulator except by replacement. Take one problem at a time. Start with the CSV system. Pull the CSV and stick it in a pail. Have someone try starting the motor when cold, while you watch the valve to see if it squirts. If it doesn't then you have to figure out why. Once you can get the motor to start cold then you can move on to the hot problem.
David Teitelbaum

[Bitsyncmaster]

Hmm, I may have to take it in to have it checked out. I don't have much to raise it up that high. (Jackstands just let me work on the oil) I don't see any gasoline on the driveway, could it be a very small drip of a leak? Any kind of special tools I need to read the pressure with?

Your concern is how long it holds rest pressure and not really what the PSI is. So you could use the air plate as an indicator to time when you have lost rest pressure. You could also guess at the rest pressure timing when your accumulator has stopped making that clunk sound.

I have replaced the accumulator and fuel filter with the back end on ramps and two floor jacks for the front. It's a tight fit for me.

[jmrydholm]

Sounds like you now have TWO problems. A bad accumulator (or check valve or leaky PPR) which is affecting your hot restarts and a problem with the Cold Start Valve affecting your cold starts. NO, you cannot "repair" a bad accumulator except by replacement. Take one problem at a time. Start with the CSV system. Pull the CSV and stick it in a pail. Have someone try starting the motor when cold, while you watch the valve to see if it squirts. If it doesn't then you have to figure out why. Once you can get the motor to start cold then you can move on to the hot problem.
David Teitelbaum

Well, the car was sitting from 2009-this June, and I actually do have a brand new cold start valve on it. Would sitting for that long damage the CSV? I had a mechanic flush all bad gas out of the tank and clean it. I also had all my injectors cleaned and pressure tested by John Hervey prior to install, so I can rule them out.

I'll try that pail method with the CSV this weekend and see what happens. Gotta worry about getting my better half's Corolla back first! This has been the car week from hell for me.