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Discussion Starter · #1 ·
OK so my rebuild of my m52(its in a 92 325i) is finally done and last night I tried starting it for the first time. I turned it over first just to build oil pressure and then I connected all the ignition coils and the fuel pump.

When I turned the key the fuel pump did not energize like it shouldve. I then checked to see if I had voltage at the pump.

I got a reading of 12 volts at the white connector w/ two yellow wires and a reading of 0 volts at the black connector with green wire w/ violet chaser and a red wire. According to the bentley manual I should be seeing voltage there too.

Checked the fuse and its good

Checked relay and its good but its not getting power.

I cycled the key like 20-30 times but still no luck.

So any suggestions to why the relay is not getting power? I have no problem diag'ing it, I was just thinking maybe there was something im unaware of that would be causing this.

Any Help is much appreciated

Dave
 

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Discussion Starter · #2 ·
OK I worked on it today for a little and came up with


Fuel pump works because I used a jumper wire from pin 30 to 87 on the fuel pump relay and it kicked on ( showed 80psi on my fuel pressure gauge which is way to high)

I have 12 volts between 86 and 85 which is correct since thats the side that causes the relay to close.

But when I turn the key to run with the relay in I have nothing.

Well off to the dealership to see if i can get some answers
 

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Help from over the pond
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3,239 Posts
If it cranks and the pump doesnt cut in its possibly crankshaft sensor...
 

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Swap the fuel pump relay. You have already confirmed that it is the problem (i.e. there is power to the control side and output side).
 

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Discussion Starter · #5 ·
Well fixed the issue, since the battery died I had to reprogram the obc. Did that and car fired right up. Nothing beats hearing your car for the first time ever.
 
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