Help - weird 318iS fuel pump behavior

[Donkeyshins]

I'm having a rather odd problem with my 1991 E30 318iS. I replaced the fuel pump last summer due to extreme bearing noise in the pump (which is usually a preview to total failure). The new fuel pump worked fin until October when it started failing randomly (the bearing started making a lot of noise as well). The second replacement worked fine until mid January when it started failing randomly as well - e.g. no start when cold or when warm or shutting down when driving. Bypassing the relay has no effect (e.g. jumping 30 & 87).

The only thing that works is to pull the seat and the fuel pump cover and unplug the power to the pump. Once it is plugged back in, it fires right up 100% of the time. AFAIK I'm not dropping below 12V (hard to measure when plugged into the pump but when disconnected it measures fine). The pump is quiet (no abnormal bearing noise) when running.

Has anyone heard of anything like this before? The last time I had to pull the plug off I bent the pins on the pump slightly askew in case it is a contact issue. I looked at the connector and don't see any evidence of corrosion.

Thanks in advance,

-Derek

[Donkeyshins]

Anyone?

[Wizard]

I had a similar problem and it turned out to be the connector (actually inside the connector)..Inside the rubber boot it must have been a bad connection with the wiring. I just cut the end of the plug and used some butt connectors (I think blue ones) to hook to the pump..
This was a bitch to diagnose at first as the pump sometimes worked and sometimes didn't with the OEM plug, although I could usually wiggle the plug to make the fuel pump come on..Problem is you have to crank the motor while dicking with the plug as the crank shaft sensor needs to sense the motor is rotating..

[Joe Gilmore]

Same here.  It was the connectors in the plug.  New female-end connector leads and the plastic snap-on plug housing which is usually brittle and needs to be replaced are all available from BMW if you want an original fix.

[Donkeyshins]

Same here.  It was the connectors in the plug.  New female-end connector leads and the plastic snap-on plug housing which is usually brittle and needs to be replaced are all available from BMW if you want an original fix.

You don't happen to have the part numbers do you?  I can't find them on RealOEM.com...

As an aside, the regulator in the alternator went tits-up last week so that may have been contributing to the problem (e.g. not supplying sufficient current to the pump).  I replaced the DME, fuel pump and O2 heater relays and the belts while I was at it (might as well since all were the factory originals and the latter, especially the alternator belt, were chewed up pretty badly).

-D

[Joe Gilmore]

The leads are 61130007442.  They are only available in green with black stripe, so you will have to mark one of them to correspond to positive.

The plug housing is 61131378408.

[Matt-B]

V regulator wont allow to little Voltage. it goes bad and allows to much. and kills accessories.


i also needed to get a new plug for pump. thanks
happened to me...