My 1996 GMC jimmy is having problems. Never had any issue with it really until this week. The starter went out 2 days ago so I replaced it. Then, the morning after I replaced it, (30 degrees) the truck would not start. It would hit, however, it would not stay running. I had to roll start the truck in order to get it running. Yea it's a 2door 5speed 4x4. I went to the parts store and replaced the fuel pump relay which seemed to help somewhat. I can't hear the pump cycle at every turn of the ignition. Maybe every other ignition turn? I go home, and this morning(40 degrees) I go to start the truck. Same issue. So I roll start it again. Truck runs great after warm and also starts up great when warm. In the past month I have replaced spark plugs with ac delco platinum which are supposed to come pregapped (didn't get to the pesky #3 plug yet). Today I also cleaned the throttle body (nasty) and the MAF sensor and replaced the air filter. I am waiting for the morning but I am about positive it will not start without rolling it off. Also, the truck makes 60psi on the fuel pressure test. And this morning truck threw CEL po440 evaporative emission system code after not starting. This is my daily driver so any input would be greatly appreciated!

 

Maybe the ignition switch? I have to replace my '98 switch yet...if I do not have the key it the right position when I turn it, it occasionally gives me problems.

 

edited....accidentally replied instead of new thread.

 

This sounds very similar to my recent problems. Any info on fuel regulator diagnostics?

 

I am dealing with a similar prob with my 1996 Blazer 4.3. I need to shoot a tad of starter spray down the throttle body when cold and it's good to go. I've been told that suspect parts are either or both the spider injector and/or intake manifold or its gasket. personally think that there is gook built up some where between the fuel tank and throttle body. I too have a brand new fuel pump and that is not the problem.

I'll keep at it and let you know how I got my baby back to good health.

 

Crap...I just realized my computer did. I read this. Thought I hit back hit Post...did not read rest.

Sorry mate was a accidental thread jack.

 

Looks like a "community thread" going on here

Testing fuel pressure and the fuel pressure regulator:

When you first turn the ignition to the RUN position, (do not start the engine) the pump will run for approximately 2 seconds and then shut off. Pressure must be tested while the pump is running. Pressure must be 60psi to 66psi. After the fuel pump shuts off, fuel pressure must remain above 55psi for at least 10 minutes. If it fails either part of this test, it means there's a problem. It does NOT identify the problem, it only tells you that a problem exists and further testing is necessary to determine what the problem is.

 

Sounds like lots of people are experiencing this or something similar. When I tested my fuel pump for pressure I did not leave the gauge on to test for leaks, so this is next on my diagnostics work.

 

Got a tip I could have a leaking injector. I looked into the throttle body and looked black. Except on the right(drivers) side there was a little gold discoloration. Carbon looked slightly thinner in fact. Possibly some washing. This could be my problem? if so what actions would I take?

 

have you tried priming the pump, turn the key to the on position until you hear the pump stop running, then try starting it?
and did it start fine before the new starter?