no power to fuel pump

[r3vde30]

89 325i


---already replaced CPS and FUEL pump with new ones
---swapped ecu as well


Car WILL start/run if I power fuel pump directly under the seat with battery pack.

So that confirms all the above work fine!!!


Checked all fuses, and fuseable link they are fine.


Which relays are which... how do i test them? Any other thoughts --- just one day to next BS !!!

[jlevie]

It is always a help to know what car you are referring to...

On an 325e/i/is the fuel pump relay should be the middle one of the three mounted on the left hand shock tower. Output fron the relay gets to the pump via fuse 11. So either could prevent power from reaching the pump.

[r3vde30]

89 325i ----

[DmcL]

fuel pump relay should be under the plastic cover next to the airflow meter, few colour variations of the relay but probably will be a brownish/red one with 4 pins on it. it can be replaced with a 5 pin relay for an E36 FWIW. i bought a new pump relay and apparently theres been alot of different replacements over the years with the current one i think being a light green one listed as an E36 part with 5 pins. thats what im using atm with no issues.

can get the part number off it if u want. bit expensive for a genuine part from BMW tho and there are cheap no name relays that should do the same job on ebay. i have one here but i havent tried it out yet, bought it for something else just noticed the pin numbers and diagram on it is identical to the pump relay i bought.

[r3vde30]

ok figured it out - when i first got the car I ripped out the alarm brain but not the wires(8 months ago)--- its a huge rats nest. Well apparently somewhere in there there is a manual fuel pump cutoff switch.

Now I didnt find the switch as Im too fraking tired to take dash apart but I found where they integrated their own wires under the seat.They cut the green/purple and then ran wires back to under dash.
I put the green/purple back togethor where these punks jigger rigged it and the test for power using jumper and voila!!! Got power. Removed jumper and car starts normally now.

Mother lover had I just sat down and thought a bit more before I threw a new fuel pump, cps, and relays............grrrrrrrrrrrrr. And screw you jigger rigging PO.

Funny thing is I was waiting all day for my new alarm to come in to install it...... think Im gonna wait a few weeks after I pull out the rats nest PO left behind.