Fuel Pump?

[piwko98]

Hey Guys -

Had the car stall out on me a few weeks ago and after trying for a while I got it fired back up. When I got him, it was making a strange noise behind the drivers rear wheel. Sounded like the fuel pump was giving out on me. I thought I should start with the fuel filter to eliminate any clogging but the noise is back and the car stalled out on me again.

It definitely feels like the car is starving for fuel at this point. Now I know the '87 e30 has two fuel pumps. One under the rear seat and the secondary near the fuel filter. It sounds like the noise is coming from the secondary one but I could be wrong. Any ideas which fuel pump to start with or anything else I might be missing?

https://youtu.be/wM4sbK5JyXM

[Update]
Did some more online reading and found an article where it talks about the Aux pump (in tank) only turning on when you are below half a tank. Sure enough, I just remembered dropping below the threshold before it stalled out. Put a can worth into it and it fired right up. Topped it off at the gas station across the street and drove it home. Safe to say it's the Aux fuel pump that needs to be replaced. Now off to research which fuel pump to replace it with... sounds like there are a few choices out there.

[turbo55]

That noise is the external, high pressure, pump alright. From what I gather when the low pressure transfer pump (aux pump) dies it puts more strain on the high pressure pump. Haven't heard about the aux pump only running at half tank. I replaced my 2 pumps with a single pump, mounted in the tank, I was having the same buzzing sound before. It's a TRE-340, put it in last year and haven't had any problems with it. I did need a little modification of the holding bracket though, so it's not a totally simple plug and play.

[piwko98]

@turbo55 - thanks!

I don't mind the setup of two pumps, any suggestion of a good aux replacement?

[turbo55]

No problem. Don't know of any aux pumps that aren't genuine BMW ones ($$$). Try realoem.com and search by the p/n of the pump. One thing I'd be concerned about with just replacing the aux pump is that the buzzing high pressure pump may be on its way out. If the high pressure pump goes out, you'd need a new genuine BMW one for that too (also $$$) since aftermarket pumps are pretty much all in-tank ones.

[piwko98]

Great points - thanks!

[piwko98]

Hitting a slight snag. Got a new fuel pump that I'm replacing but while taking out the fuel sending unit, one of the 4 blots is just spinning and not coming out. I tried any which way i could to get it off but no luck, just loosely spinning there.

Any thoughts on how to get it out? Is it safe to assume that the whole fuel pump kit will need to be changed out as the thread is more than likely shot here?

[Update]
Was able to get the parts out. Not a fan task when the bolt is stripped. Looks like it's time to replace the entire part.

[piwko98]

I just got a used fuel pump and didn't realize it's a post 09/87 one. Slightly different than my pre.

Looks like the top has only one 1 fuel line in whereas the old had two. Guessing it's a no go but figured I'd check. Pictures coming soon.