Ogunvette88

I have replaced the following:
Fuel pump, fuel pump relay, fuses, oil sending unit, oil pressure switch, distributor cap & rotor, coil & spark plugs. Still no start and no fuel pump action unless I jump the pump off directly. What could be preventing the fuel pump from energizing when I turn the key?

Cliff Harris

Does the fuel pump run for 2 seconds when the ignition is first turned on? That is controlled by the ECM through the fuel pump relay. The ECM turns on the fuel pump when it sees DRPs (Distributor Reference Pulses) from the ignition module inside the distributor. If you don't have DRPs (engine rotating) the fuel pump will not run. The DRPs are also used to synchronize the firing of the injectors to the rotation of the engine.

kael

After the initial two seconds at key on, fuel rail should have pressure, 35+psi. If not seeing this, then time to check the ECM. Check the error codes with paperclip method and see if code 12 is shown. If not, ECM needs addressed.

aklim

Does it ALWAYS do this? My 91 DOES NOT. Say I go there and turn the key to "RUN", it will prime. Shut it off and immediately turn it to "RUN" and it will not. Only after a certain number of minutes of "WAIT TIME" will it prime again. IOW, I am only able to prime it every so often and not every key turn.