On an 85 iroc 305 tpi. Should the fuel pump always start when the key is turned to the accesory setting. Or does the system hold pressure for a short time. My car does not always want to start right up. I thought that it may have been the relay. because the fuel pump does not start every time the switch is turn on. Any suggestions would be helpful. I did change the relay just to see if that fixed it and it seems to do the same thing? Bad relay? thank you Kris

 

85Rock,

Welcome Aboard!

The fuel pump relay should not run with the key in the ACC position. It should operate for about two seconds when the ignition is turned to RUN. It will also operate as soon as the ECM receives reference pulses from the distributor (engine moving).

Also, the pump relay will not operate on successive ignition power-ups unless the ignition power has been off for at least 20 seconds.

Verify the fuel pump relay operation. If the relay is operating correctly (on power-up) you need to monitor the fuel pressure. Your stock injectors require at least 33 PSIG to operate satisfactorily, and should normally have 38 PSIG (+/- 3 PSIG) with the engine running.