I have replaced the fuel pump, the filter, the relay & the ICM. I let it run for about 15-20 minutes & it will not start bck up til it cools down. Can someone help? It is a 95 4.3 2nd gen motor....ICM is on coil.

 

Does it have a nice blue, (not orange) spark at each plug while cranking? What is the fuel pressure when it won't start?

 

It turns over quickly but will not start until it sits for about an hour. then it just runs for short time but if it sits over night it will run about 15-20 minutes.

 

We need to know if it's losing fuel pressure or ignition, see post #2

 

what psi should it be?

 

2 different systems were used in 95, need to know which one you have.

This is CMFI:



This is CSFI:

 

I have CMFI

 

When the ignition is initially turned to the RUN position, (engine off) the fuel pump will be activated for ~2 seconds and then shut off. This time frame is referred to as "pump prime" and fuel pressure must be tested during this time. Fuel pressure must be 55psi to 61psi and must remain above 50psi for at least 10 minutes.

 

I have eliminated the fuel pressure it is holding 59psi

 

Next step is check for a blue, not orange, spark at each spark plug.