wont start when warmed up

Hello Customer (name blocked for privacy), the main thing that seems to be a concern is the fuel pressure. Am I correct, you are saying that when the vehicle shuts off the fuel pressure is 50 psi for a moment and then it imediately falls to 0?

that is correct. turn key on and not start i have 50 lbs pressure turn key off it drops almost immediately to 0.

This is kind of a transition year vehicle, can you tell me if you have a big round air filter on top of the engine, or is your air filter in a square type housing unser the hood?

filter housing is just behind radiator and is square

the fuel line go into the manifold just behind the throttle body.   the injector conections are behind the fuel lines in the manifold

On your engine does it have a plug like on the picture c104.

Images available only to Customers.

correct sorry about the delay your e-mail didnt come thru. and i shut down this site.

Edited by Customer (name blocked for privacy) on September 6 2006 at 9:11am

Okay, these engines have a problem with the injector poppet valve getting stuck causing the kind of problem you are having. You may also have a problem with the fuel pressure regulator. The injector assembly is under the intake manifold. You can usually have it cleaned by the dealer or anyone else with a top end cleaner. Most in tank cleaners will not fix it.

is the pressure regulator under the manifold also?

Yes, it is actually connected to the back of the injector poppet assembly. Do you still have your fuel pressure gauge?

yes

Before anything see if you can clamp off your fuel return line. If you cannot you will need to try unhook the line and plug it off. Hook up the gauge and see if you get your 50 psi of pressure. Then watch the gauge and see what happens. If the pressure still bleeds off then your regulator is not at fault. If it stays up then suspect the regulator. Let me know if you have any problems.

i pluged the return line, when pump quits running guage drop off 50% then slowly bleeds off completely. it did the same thing with return line hooked up. would a bad regulator cause it not to run even when the fuel pressure is still good?

It doesn't sound like the regulator is the problem. If the pressure is still bleeding off even with the return plugged then it sounds like the injector poppet it sticking. I would recommend finding a shop that can do a proper injector cleaning. One that actuall hooks to the fuel line and completely cleans the system.

i will have an injector cleaning kit tomorrow and will try it   thanks

Not a problem, let me know what happens.

i run a can of injector fluid thru system. when i went back to fuel, it would not start. 1 shot of either and it fired up. it ran for about five minutes, then i goosed it and it died and wouldnt restart.   help

Double check to see what your fuel pressure is reading now and let me know.

fifty lbs. when running, after engine quits it drops to 20 then slowly goes to 0

How long ago was the fuel pump changed? Was it recently?

about a year ago maybe 25,000 miles on it

Edited by Customer (name blocked for privacy) on September 7 2006 at 4:10pm

With your fuel pressure tester is there anyway that you can hook it to just the pressure line, with the pressure line plugged before it goes into the injectors?

i've shut down for the night. will try to tie into the filter in morning. thanks

Let me know what happens. Sorry this is taking so long. Hopefully we will find the culprit soon.

same result goes to fifty, the relay quits and it drops to twenty then slowly goes to 0. i say slowly but it only takes about 30 seconds. i always have pressure when the engine quits. could a fuel pump put out pressure and no fuel?

Yes, that is what it seems like is happening. Right now you should have just the fuel pump isolated in the system. After it builds pressure it should continue to hold it there. Also the pump can build pressure but have no volume. If you are hooked directly to the pump output line then I would say you need to drop the tank and check the pump. Pay close attention to the small rubber hose between the pump and main housing.

the hose seem loose the wiring burned up replaced pump wiring screen pressure is 57 lbs when turned of it drops to 40 lbs and very slowly bleeds on off.   road tested vehicle and it is running fine. i sure do thank you for all your assistance.   rich

THIS ANSWER IS LOCKED!
You can view this answer by clicking here to Register or Login and paying $3.