Hey Guys,

A little while ago, the 85 Ciera just quit on me while I was driving. I took it in and got the fuel pump replaced, but after there was fuel in the lines it still wouldnt start. So they found it to be the pick-up coil and replaced that and it started working.

When I got the car back, I noticed the fuel pump would not shut off like it normally should after 2 seconds. Anyways I kept driving it like that, and a few months later it died again. Fuel Pump failed. I got it replaced under the warrently but its still running all the time.

They suggested a wiring problem.

I was trying to find out more information as the circuit for this car and how the fuel pump prime connector and fuel pump relay work.

The Pump still runs even with the relay disconnected and the oil pressure switch not even in the engine.

Im thinking either there is a short somewhere in the system, or the ECM needs to be replaced.

I applied battery voltage at fuel pump prime connector to test if the pump would run when it died. But im thinking that caused either a short or ecm failure.

Any ideas??

Thanks!

Well...

Try removing the fuel pump fuse (10 amp), does it still run then?

You said the "oil pressure switch not even in the engine", does that mean electrically disconnected?

Since it still runs with the fuel pump relay removed, which is controlled by the ECM, the ECM is not the problem. Sure you pulled the right relay (closest to A/C Accumulator)?

Applying power to the fuel pump priming connector will not damage anything, as it is applying +12V directly after the fuel pump relay (ECM is connected to the coil of relay).

TOC Admin
Brando