Im hoping someone can help me with my problem. I have a 87 GT with a S/C 3800 series 2

Here's what's happening:
when I started the car it was running rich after doing some trouble shooting I found 2 injectors were bad. I replaced the 2 bad injectors and it ran great for about 10 minutes and then died. I checked all the injectors again and swapped out the fuel pressure regulator and they all seem good. When I hook up a fuel pressure tester and turn the key on and the fuel pump is priming the gauge reads around 55-58 but as soon as the fuel pump shuts off the gauge goes right down to 0

Any idea's or things to test?

Aaron

This is somewhat common... I have seen a few things cause it, but usually its a internal leak from the fuel pump to the sending unit. It could also be a bad/non existant checkvalve in the fuel pump, or a goofy pressure regulator... although they never really fail like that.

Overall, its not really a problem as long as your fuel pump doesnt shut off, and you still have fuel pressure at wide open.

quote Originally posted by darkhorizon: This is somewhat common... I have seen a few things cause it, but usually its a internal leak from the fuel pump to the sending unit. It could also be a bad/non existant checkvalve in the fuel pump, or a goofy pressure regulator... although they never really fail like that. Overall, its not really a problem as long as your fuel pump doesnt shut off, and you still have fuel pressure at wide open.

What he said.....I have seen some swaps hold there pressure while others drop to zero and others slowly bleed off. Pressure seems high as it should be around 48 PSI with out vacuum.....

Did this engine ever successfully run in the Fiero for more than 10 min?

No that was the longest i have ever ran the motor at this point

So when you bump the starter does the fuel pump turn on? Do you get a MIL light when you turn the key to on - engine not cranking?

Did you check for spark?

What was the problem you found with the two injectors?

[This message has been edited by phonedawgz (edited 01-02-2012).]

The fuel pump kicks on and the MIL light is on at key on. I pulled the Fuel rail out and left everything connected and turned the key to the on position and they were leaking. I replaced the 2 injectors and checked them again and were no longer leaking. I have not checked for spark yet thinking it was still a fuel problem

If the PCM turns on the fuel pump when you bump the starter it means the PCM is getting seeing that the ignition is working. If the PCM doesn't see the engine turning (ignition) it won't fire the injectors. Your engine could have ran on the stuck on injectors for that short time, perhaps.

Check the voltage on the pink wire of one of the injectors during cranking. Then check the voltage of the other wire of the injector during cranking. If you see the second wire dropping about 4v as compared to the pink wire during cranking that will show you that the PCM is firing the injector.

[This message has been edited by phonedawgz (edited 01-02-2012).]

Save your self a lot of time and go buy or borrow a set of noid lights to test and make sure the PCM is firing the injectors properly then it is either a fuel pump related problem as mentioned a bad fuel pressure regulator or start looking at spark related things. Dan

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



http://www.photosled.com/showgallery.php/cat/631