Fuel pump wiring issue
02-03-2019, 04:43 PM
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Fuel pump wiring issue
Hey guys I'm new to the forum and I'm terrible with electronics. A few months ago my gas guage pinned to the top. No problem I just started filling it up twice a week. Well about a week and a half ago my car started running funny, as in it would stall without applying throttle. It did this for two days, and on cold starts it would run without throttle but very wildly with the rpm's going all over the place. Then it stopped running entirely. I noticed my fuel pump doesn't prime and heard a groaning noise from the fuel pump relay. I replaced the relay which stopped the noise but fuel pump still doesn't cut on. I checked the fuses under dash they're all good. I replaced the pump itself only a few months ago so I doubt it's the culprit. Nevertheless I pulled it out of the tank and checked the wires with a multimeter. It read less than 1 volt. I think this might be the issue unless I did it wrong but I also checked the plug behind the backseats. The middle socket had a continuous 9 volts and the driver side one had a continous 0.12. Shouldn't one of these shut off after 2 seconds? I just have no idea what to do and hope someone good with electronics could help me out.
Edit: after leaving the key on for a while the new relay started to groan like the old one, and every time it does the volts spike.
Edit: after leaving the key on for a while the new relay started to groan like the old one, and every time it does the volts spike.
Last edited by Smashdragon383; 02-03-2019 at 11:39 PM.
02-04-2019, 03:23 PM
#2
Re: Fuel pump wiring issue
Iirc the purple wire is the gauge sender and black is ground . The fuel pump relay gets 12v from the ecm for a 2sec prime on a green/white stripe wire. The wire going from the relay to the body connector is grey or could be tan with a white stripe I think depending on year. The 9volts seems low so maybe there is a connection issue at c100 body connector bye the master cylinder. As well as a issue at the pass through connector at the rear of your car.
02-04-2019, 05:56 PM
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Re: Fuel pump wiring issue
I figured it out. I have a short somewhere between the battery and the relay. I noticed I got 11v with key turned off, and it dropped to 2 when it was turned on. I straightwired the battery to the relay and it cut on for 2 seconds like it should. Haven't tried running it yet due to my sending unit being out but I'll make an update in the morning
03-09-2019, 05:47 PM
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Car: 82 Z28
Engine: 350 LT1
Transmission: 700r4
Axle/Gears: 3.73
Re: Fuel pump wiring issue
hey guys/gals need help my fuel gauge pegged and it wont come back down need help to fix please
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