chevy Posted November 23, 2008 Report Share Posted November 23, 2008 got a 92 lumina Z34 when i turn the car off the fuel pump stays on i have never had problem like this disconnected the battery so it dont run my battery dead over night. any help would be great thanks Quote Link to comment Share on other sites More sharing options...
White93z34 Posted November 23, 2008 Report Share Posted November 23, 2008 maybe a failed fuel pump relay? Quote Link to comment Share on other sites More sharing options...
Pontiac6KSTEAWD Posted November 23, 2008 Report Share Posted November 23, 2008 Failed fuel pump relay would be my guess as well. Instead of disconnecting the battery, try pulling the fuel pump fues in the underhood fuse panel. Quote Link to comment Share on other sites More sharing options...
rockfangd Posted November 23, 2008 Report Share Posted November 23, 2008 definately stuck fuel pump relay Quote Link to comment Share on other sites More sharing options...
chevy Posted November 23, 2008 Author Report Share Posted November 23, 2008 Were is the relay, under the hood? or under the dash? Quote Link to comment Share on other sites More sharing options...
AL Posted November 23, 2008 Report Share Posted November 23, 2008 underhood... its right behind the airbox and battery and washerfluid area... you will see it... ill see if i can get a pic Quote Link to comment Share on other sites More sharing options...
AL Posted November 23, 2008 Report Share Posted November 23, 2008 here you go Quote Link to comment Share on other sites More sharing options...
5speedz34 Posted November 23, 2008 Report Share Posted November 23, 2008 slightly different on a '92 but that should work. Quote Link to comment Share on other sites More sharing options...
slick Posted November 23, 2008 Report Share Posted November 23, 2008 That, or make sure that single red wire isn't connected up to the battery, or aux terminal, at all times! Quote Link to comment Share on other sites More sharing options...
carkhz316 Posted November 23, 2008 Report Share Posted November 23, 2008 NO! It's the oil pressure sending unit. It gives power to the fuel pump in the event that the relay fails or fuse blows. So long as there is something like a few psi of oil pressure (normally while running, duh.), it will provide power so your car still runs. when the sending unit fails, it will cause this scenario where the pump will run even with the key off. Quote Link to comment Share on other sites More sharing options...
Olds W31 Posted November 24, 2008 Report Share Posted November 24, 2008 NO! It's the oil pressure sending unit. It gives power to the fuel pump in the event that the relay fails or fuse blows. So long as there is something like a few psi of oil pressure (normally while running, duh.), it will provide power so your car still runs. when the sending unit fails, it will cause this scenario where the pump will run even with the key off. Â Agreed. Unplug the oil pressure sender and the pump will stop. Quote Link to comment Share on other sites More sharing options...
rockfangd Posted November 24, 2008 Report Share Posted November 24, 2008 that is also possible but i have never seen a sending unit power the pump with the key off. There is no power going to the sending unit when the key is off i believe. The only thing that gets power is the FP relay That i know of Quote Link to comment Share on other sites More sharing options...
Olds W31 Posted November 24, 2008 Report Share Posted November 24, 2008 i have never seen a sending unit power the pump with the key off. There is no power going to the sending unit when the key is off i believe. Â Ummm, no. The way that I know this does happen is from the experience of testing diff sending units to try and make my gauge (oil press) actually work, instead of swing to 2/3rd and hold. I swapped in a z28 sender and the cutoff was too low, so when you turned the key off, and depowered the ignition, the engine would shut off, but there was this strange "whining" coming from under the car (fuel pump). Â Opening the hood and unplugging the sender depowered the pump, as well. The keys where in my pocket for this part of the experiment. Â BTW, the old, correct, non-indicating sensor went back in the car when I got back home.... Quote Link to comment Share on other sites More sharing options...
carkhz316 Posted November 24, 2008 Report Share Posted November 24, 2008 Here ya go dude. If you can read a schematic, you'll figure this out then, but firstly check out your oil pressure gauge. Does it go "wacky" or spike either way ever, because this fuel pump issue will usually coincide with a failing sending unit. Look at the pic, you'll see that even if you pull the relay AND the fuse, the pump can still be run via the oil pressure sending unit. Quote Link to comment Share on other sites More sharing options...
spiderw31 Posted November 24, 2008 Report Share Posted November 24, 2008 Looking over that schematic, yes the fuel pump will run with the relay out, but NOT with the fuse removed. Voltage is coming through the fusible link and fuse into the circuit, and into the ECM B+ terminal. Quote Link to comment Share on other sites More sharing options...
carkhz316 Posted November 25, 2008 Report Share Posted November 25, 2008 whoops, my goof. I know the condition though, and the rest of it I knew for sure since I've come across many times. Quote Link to comment Share on other sites More sharing options...
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