Odd fuel pump issue

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Bristol_Jer
E30 Zone Addict
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Post Wed Aug 28, 2013 7:53 pm

I've fitted a new fuel pump (brand new) to my e30.

The car didn't start after I fitted it, so I checked if there was still power to pump when cranking, and there was. So I check if there was still a spark, and there was.

So I then disconnected both fuel hoses from the engine that come out from under the passenger footwell and stuck them in a jam jar, no fuel out of either when cranking the engine, and pump still has power. All points to a dead pump I thought, but the weird thing is when I disconnected the hoses from the engine, there was a loud hiss out of one hose, and fuel p1ssed out of both of them. Also when cranking the engine, the car smells a bit of fuel inside near the fuel pump but theres no leaks that I can see

The connector on the new pump is the same as the one on the car, and fits snugly. I can't hear the pump running, but my engine is pretty loud when turning over. Is it possible to put my multimeter in-line to see if it is drawing current, or will that fook up the mulitimeter?

It's just weird how there was pressure in the hoses, but nothing came out when I tried them both in the jam jar :mad:
jimbom30cab
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Post Wed Aug 28, 2013 8:12 pm

the pressure in the hoses might be residual pressure from the fuel manifold??

if there is no fuel p1ssing out when the ignition is to start then the pump is not pressurising.

I think it could be the pump isn't priming with fuel, are you sure there are no inlet or strainer covers to remove or the pump is definitely sitting in petrol not air ??
Bristol_Jer
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Post Wed Aug 28, 2013 8:26 pm

Theres 3rd of tank of fuel in there, I'm 99% sure there wasn't a bung in the bottom of the pump, as I had to fit the strainer, but I'll whip the pump back out again and make sure 100%. Good call Jim :)

Also to add I had a good look around in the tank when I had the pump out and there was no crud or any little bits in there, and the fuel filter was changed less than 500 miles ago
daimlerman
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Post Wed Aug 28, 2013 8:57 pm

The fuel pump will run even if connected up the wrong way round,in this case it sucks instead of blowing,as the actress said to the bishop... :D
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