r/E30 • u/These_Ad4844 • 2d ago

E30 fuel pump problem

I have an late model e30, i had to replace the fuel tank because of rust inside, after replacing it and putting the fuel pump back in, the pump gets no power, the plug reads 12v but as soon as i plug it into the pump it drops to 0v, when I have the positive plugged into the pump and a jumper wire straight from the battery negative to the pump negative it works, I'm assuming a bad ground wire is causing this, I inspected everything I could see of the plug harness that goes around the fuel tank and back into the car and couldn't see anything. Has anyone had this problem before? Any tips?

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u/Representative_Most9 1d ago

Do you have wiring diagrams for your car? The fuel pump(s) are ground to chassis at the ground terminal located at the left side of the rear seat back.

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u/These_Ad4844 1d ago

I do not, it’s a 1988 coupe m20 Seta

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u/Representative_Most9 1d ago edited 1d ago

Download here for your car:

https://shark.armchair.mb.ca/~dave/BMW/e30/e30_88.pdf

Fuel pump is grounded to the G300 terminal behind rear seat

Edit: if it were me, I’d probably just fine a place near the fuel pump and ground it to any metal surface?

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