Fuel pump will not prime?

[BillyBoost]

My fuel pumps have stopped primeing when the switch is turned on. The fuel pressure will not come up and the car is hard to start. I can pump the gas and the car will start and pressure is normal. Once the car is cut off the fuel pressure drops to 0 immediately. Any ideas?

 

[Steve Wood]

May be two problems...the no prime problem is probably a bad fuel pump relay.

 

[Ken Cunningham]

The fuel pump prime is commanded by the ECM. A bad ECM, or just a bad connection, can also cause a failure to prime.

 

[Turbo Brian]

After you check the fuel pump/inj fuse, check the dark green/wht wire going into the fuel pump relay. If the fuse is good and there is no power in the green/wht wire, when you first turn on the key, you have a bad internal computer connection to pin A1 (fuel pump prime circuit).

There will only be voltage in the green/wht wire during the time that the fuel pump prime circuit is active. In other words, it is controlled by the computer and only has power during the first 10-15 seconds after the key is turned on.

I have a bad computer in my spare parts box that did have a failed prime circuit. I solved the problem with another computer from Red Regal T.

 

[BillyBoost]

Car has Speedpro (FAST) so i guess that rules the ECM out...

I'll check the relay.

Running the car today and noticed that after the car has run a while the prime will activate...it seems to only not work after the car sets a while??