fuel pump won't prime

[SIXBANGR]

It is the ecu, if I try another one it works. What could be wrong? Is it the little chip next to the eprom?I can also run a wire to the fuel pump feed under the hood but would like it to work correct.

 

[Way2QWK]

A friend of mine has the same issue with his. Fuel pump will not turn on until the oil pressure switch sees pressure. Is yours like this too. We just sent the ecm to Bob Bailey to see if he can find the fault in the fuel pump circuit in the ecm. You can run 12volt cranking voltage to the oil pressure switch to complete the circuit.

 

[SIXBANGR]

I'd say it is the same. If you crank long enough it will start.

 

[bison]

Fuel pump relay is shot or there is an open circuit or corroded wire. Simply replace it and your good to go. GM put in the bypass in case of failure of the relay.

 

[Scott Atk]

I had the same problem sort of... My fuel pump would run constantly anytime the key was on. Swapping the ECM fixed it.

 

[Boost231]

Im the one that sent Mr. Bailey the ECM. Not sure whats wrong with it yet. i havent heard back from Bob but he probley just recieved it a few days ago. The problem with my ecm is it wont cycle the pump. its not the relay as it has been verified on 2 other cars. the car will start once it sees oil pressure thus completing the circuit. The reason i didnt just swap ecms is because my ecm has the low z drivers in it.

 

[SIXBANGR]

mine was modded too, so would like to keep it.Keep us posted on yours.

 

[JDEstill]

I copied this from another thread awhile back, sorry I can't give the original poster credit. Maybe it will help:
"IF the oil pressure sending unit is unplugged and IF, the fuel pump relay is faulty, then the pump will not run, and no start. The oil pressure sending unit and fuel pump relay are in parallel, which is why the fuel pump relay can be faulty or removed and the car will still start and run as soon as oil pressure comes up during cranking. But one of them needs to work."

John

 

[GN Bob]

I had the same problem with the pump not priming when the key was turned on.

It turned out that a T-top water leak ended up corroding the fuel pump prime pin on the ECM. I sprayed the pin with contact cleaner then scraped it very lightly with a points file. I also sprayed and cleaned out the mating connector female terminal with a paper clip, it was coated with green copper corrosion. I then put a small amount of dielectric grease on the terminals and its been 5 years and no fuel pump priming problems.

Bob