M30 fuel pump question.

[Heysüß]

Just bought Zacm829 's swapped m30. says the fuel pump is stock.

Thinking that's the problem since it's not making a peep when i turn the key to listen for it, since it's pretty worn looking and easier to replace than my last car was (chevy s-10) think i should just go ahead and get a new one ?

i'm not great at the electrical troubleshooting stuff, so if there's anything you guys think I should check first let me know. assume I'm a dumb ass when telling me step by step how to check the wiring on this car.

sorry if i didn't use google or the search button on here as well, this is my only car so I have to get it running as soon as possible! thanks for the help guys!

[Jean]

It only works when the engine is spinning and cps is sending signal to dme.

[Heysüß]

Thanks. I already bought some pumps from adv auto but I'll try to listen for it again while cranking. I already checked fuse 11 and the middle relay (jumped it how someone else did) and nothing happened. Although it is safe to assume that I fucked up checking the electrical aspect of this problem. Hopefully this works, I need my only car to work.

[Jonsku]

Try it by putting the fuel line in to some canister, crank the engine for some time and check if there's any fuel coming to the canister ?

[Heysüß]

kiitos! I have some time in between two classes tomorrow so I'm gonna try and see if i get anything out of the output side of the fuel filter as well. If I don't get anything there I'll try before the fuel filter and If nothing then I'll just change both pumps.

[Zacm829]

Fuel filter was replace around 8k ago. My bet would be the fuel pump took a shit. Also check that the cps (front of the engine reading the toothed wheel is tight), I wiggled loose on me once before. Good luck you should have it running in no time.

[RickSloan]

you can also jump the fuel pump relay.

if when you jump 30 to 85 i think you should here the pump kick on. if it does kick on then the relay is bad.

[Heysüß]

yeah i already did that, I saw a pic of someone doing it. jumped left column middle slot with middle column bottom slot and nothing happened there, fuse 11 has continuity.

just to be sure it's the middle yellow box for ALL e30s right ? that's the relay i checked for the pump.

[Heysüß]

well... the fuel pump was being twitchy. When we hooked it up to run 12 volts it threw up a bit of fuel and that was it. So i put a new bosch fuel pump in. and I made sure the CPS was sending the signal to the pump so i cranked while the old man assured me it was in fact pumping (he could hear it humming).

so now tomorrow I'm planning on checking to make sure the fuel line isn't somehow clogged.

so to recap:
The CPS sensor is fine because the pump is pumping and the relay and fuse are also ok. so now all there is to check is to make sure the fuel reaches the front correct?

in the front am I correct in assuming this golden cylinder being the FPR and disconnecting this to make sure fuel is passing through the filter and coming to the front? is there anything else between this and the fuel filter?

thanks for the help, hopefully I'll have a car again soon!

[Garageaholic]

Why is your FPR in the rear of the engine bay? It should be in the front. I've never seen that setup before on an M30.

[Jean]

I've seen one or two e34 cars with the self leveling systems and they had a wierd fuel rail AND harness was different as well. Maybe that's where it from?

[Heysüß]

as far as i know the fuel pump is stock m20. and yes that's exactly what we said, it was weird that the FPR was at the back.

i guess my real question here is: I remove the top thicker hose to make sure the fuel is reaching at least the FPR right ? or is the bottom the arriving fuel ?

[Jean]

Bottom one is a vacuum line.

[Heysüß]

ok sweet. so I pull the top hose off, don't get nothing out that means it's somewhere between there and the pump. or is the vacuum line there as an aid to help it get the extra length ?

sorry if this is a dumb ass question.

[Jonsku]

FPR is one-way valve, so if you try to push the fluid to wrong direction it won't move.. Do you still have another FPR in the front of the engine where the fluid gets back to tank?

I'd pass the FPR in the rear and just plug the in-hose directly to fuel rail..