Topic: 92 Pontiac Grand Prix

[stereopunch]

The car keeps killing on me But will start after it sits for about ten minutes So I tried a new fuel pump and same problem continues I noticed when i try to start it after it kills I can't hear the fuel pump running I've had it hooked up to all kinds of diagnostic machines but of course it wouldn't kill when on a machine any ideas would be greatly appreciated

[barrie1]

Welcome Stereopunch to the Forum. Have you had your starter looked at lately. When starters are hot right after you shut down the engine and the car won't start I would look at the starter as the brush's may be tired especially if it is the original. It takes more power to turn it over when hot and may not be turning fast enough to start until it cools down a bit. Your fuel pump should stop pumping fuel after the pressure is up unless the engine starts. No pump, No noise.

[duck]

Right-on Barrie.  








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(Message edited by duck on February 19, 2005)

[articsteve]

Mark; are you meaning to say that the car engine "turns over", but will not fire?

If so, I would say your fuel pressure regulator is not functioning (not uncommon and not expensive) and it is causing your fuel pump relays to fault because they are getting the singal that the fuel pressure is exceeding what is a safe operating pressure.  

That is perhaps why it takes 10 minutes to actually fire up after it dies because it takes ten minutes for the pressure to back off.  Hotter the motor the worse it is.  You need a mechanical check of the pressure in the fuel rails.

[barrie1]

I agree with Artic on this if your starter is working alright. Definitely makes sence to me.

[exserviceguy]

Hi Ho Stereopunch and gang, hate to rain on the fuel press reg parade, but on a 92 Pontiac and most other cars I know, the fuel press reg doesn't report to the ecu or pump relay.  The reg simply takes a vac signal from the intake to increase fuel press at the rail when engine load demand is high and vac is low.  No electronics involved here.  Yes a fuel press reg fault can starve injectors and make restart a load of fun, but the stall out will be more of a stumble and gradual affair not the sudden die out that I think we are speaking of here.  If the GM ignition module/coilpack is getting tired it is prone to thermal failure where it shuts off the ignition like you turned off the key and has to cool down before restart occurs.  The crank postion sensor can do the same thing, and if the ecu doesn't see a crank signal, guess what, it won't engergize the fuel pump.  Rather than continuing to throw some expensive parts at this, get a shop with a good scanner to find out what signal or system is failing when it won't restart, (this obviously will neccessitate leaving the car with them for a long road test.)

[barrie1]

It is becoming evident that his car needs to go on the proper diagnostic equipment and be diagnosed correctly. There are times when spending the money is the cheapest route to fixing something and also the fastest. A trip to the right diagnostic machine is in order here.

[articsteve]

Alright, well Mark should have tested his fuel pressure before he went to the expense of installing a new fuel pump.  Although, he should still place a gauge on it and see how his regulator is working and see what his holding pressure is 30 minutes after shut down.  But since he says it just dies on him while driving, doubt he is suffering from vapour lock which could be associated with delayed hard start and the fuel system.

So I am jumping on the ignition/coilpack fix like you suggested because you know the vehicle and second to that, a weak fuel pump relay that heats up and shuts down temporarily.  Crank position sensor usually doesn;t kill a car in motion over and over again.  It does cause delayed no starts. It was standard to have 4.0 jeeps have no hot restarts because of the crank sensor.  

Whatever he does he should go to a wrecker and get these parts.  Must be zillions of these motors around in the states.