1991 525i fuel pump voltage problems

I have a 1991 525i that has no voltage at the fuse for the fuel pump. I have changed the relay for the fuel pump already, can someone tell me where to check next?

Reply to
John J
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The ECU controls the pump and it also connected via the speed limiter which in your case is not needed as the car won't touch 155mph but it is still controlled by the ECU - perhaps it gone dead.

Reply to
hsg

Okay, as I recall, the fuel pump is powered by the fuel pump relay, which is powered by the main relay. Main relay has power at all times, which it gets through a fusible link right off the battery, right?

The electrical manual will tell you for sure, and barring that you can take the fuse box apart and see where the wires go. You sure the main relay is good? Put the relay you took out of the fuel pump position into the main relay spot.

--scott

Reply to
Scott Dorsey

Reply to
John J

My local dealer insists that the Bosch relays "never fail" and that if there is some electrical problem the relay is the last thing to check.

He's wrong. And there are a _lot_ of relays that all need to be working right.

--scott

Reply to
Scott Dorsey

My 1991 318ic has the same issue and the relays have been replaced. At two separate times the car stalls and will not restart even after sitting for a few hours. But a short ride on a tow truck seems to shake the car enough that it will always restart and run.

The first time this happened the local BMW shop tested the pump and replaced the relays but they could not reproduce the problem.

Any suggestions on what can be the source of this?

Reply to
RandyD

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