Can someone please tell me where the fuel pump relay is located on a 92 Z28 with a TPI 350????? Thanks, mine was staying on with the key off, and now won't come on with the key on.....Tom

 

If your relay setup is like mine, you will have in line the EST, Maf Burnoff Relay, Fuel Pump relay and Maf Power Relay. So if you have three relays in a row, the middle relay should be the Fuel Pump. IIRC, all three relays are the same, so you could swap out the MAF Burnoff Relay to the FP position to see if it works.

 

firewall by the master cylinder

 

If your fuel pump is constantly running, chances are it's not the relay, but the Oil Pressure Sending Unit making the pump run always.

The relay ONLY gets activated with the ECM, which only gets power with the key on - so there's no way the relay can be activated with the key off.

BUT - the OPSU gets 12v+ directly from the battery, and is a backup circuit for the fuel pump (in case the relay or the ECM go bad, the OPSU will make the pump run when it senses oil pressure). And thus the OPSU can run the fuel pump 24/7 regardless of the key (if it goes bad in such a way that it "thinks" it senses oil pressure when in fact there is none).

Now - this doesn't mean that your relay could be bad as well - but the relay cannot be the culprit of a constantly running fuel pump.

At this point, it's possible that your relay is fine, and that your fuel pump could be burnt up from constantly running.

BUT - check the fuse for the ECM/fuel pump first before assuming a dead fuel pump. It's undert he hood, between the battery and the fender (sometimes attached to the fender), in a small weatherpack all by itself - it's a 20 amp fuse, and the weatherpack has a red wire in (from power distribution block) and a orange wire out (to ECM and OPSU).

Hope that helps!

 

I second the oil pump switch...

This just happened to me about 6 months ago with my 89 TBI 'bird. Also, beware the auto zone replacement oil pressure switch. I had a brand new one die the first day. A quick search on here told me that its common for those to continue going bad, one way or the other (constant on or never on.)

If you can get the real AC Delco part, you'll win.

 

Thanks guys, I would have never thought of the oil pressure switch...I thought the contacts in the relay had fused together....I will check all you have said....Tom

 

Bad relay, The case had cracked, and water got in it somehow....