Fuel Pump wiring schematic

[r3d e30]

Does anyone have or know where I can get a wiring schematic for the wiring to a fuel pump on an 89 325i. I have turned my bentleys upside down and cant find one.

[DaveSmed]

The Bentley sucks ass for BMWs.

[r3d e30]

Thanks, and yes Bentleys sucks for BMW.

[StereoInstaller1]

Go download your ETM (Electrical Troubleshooting Manual) from www.wedophones.com

[r3d e30]

Thanks for the info.

[tokky28]

I'm also looking or more information on the wiring to the fuel pump relay on my e30 convertible. Since I have a front battery, the wiring diagram on my car shows that terminal 30 is connected directly to the battery. I want to know its full path back, because I'm trying to trace the source of its voltage drop. The terminal on my car reads only 5V, and I can't start the car. If I provide a direct source of 12V to terminal 87, the fuel pump runs and I'm able to start.

Does anyone have knowledge on this?

Thanks.

[cabriodster87]

^ Maybe the relay is shotski

[tokky28]

But the 5V reading is from the relay holder corresponding to terminal 30 not the relay itself, so the issue has to be along the wiring towards the battery, right?

[cabriodster87]

Should be 12v at term 30 (red wire) correct. The wires at the bat (+) check there first. make sure they are connected properly.

[tokky28]

Yeah, that's what I think. Is the wire connected directly to the battery, or is there an intermediate connection? I don't see a thin red wire there. My battery is located in the engine compartment. Thanks.

[jlevie]

The ETM shows pin 30 as powered directly from the junction block in the engine bay. But I have found it to be powered from the ignition switch via pin 6 of C101 . See if pin 30 is hot when the ignition is off. If it is the car is in the configuration shown in the ETM. If not it is in the undocumented configuration.

For the case in the ETM a high resistance could at the relay socket contact, in the wire from the relay to the splice in the harness, at the splice, or power lead that feeds the splice. If the problem is in the harness you'll need to remove it from the car and cut it open to find/fix the problem.

For the undocumented case place a jumper between 30& 87 and turn on the ignition. Then trace back through the circuit to find the point where you see system voltage. The fault will be between there and the relay.

[tokky28]

Thanks Jim, mine is hot with the ignition off. In fact now that the engine is cold, it's showing 12 v again. It there a junction block for convertibles where the battery is located in the front?

[jlevie]

Thanks Jim, mine is hot with the ignition off. In fact now that the engine is cold, it's showing 12 v again. It there a junction block for convertibles where the battery is located in the front?

Seems like there should be since the the vert shares parts with coupes & sedans. But since I've never had a vert I can't say for sure.

The power for the relay is via the DME power leads that connects to the small cable (containing the fusible link) from the battery positive. There is a splice in the harness that feeds the wire running to the relay socket. A bad fusible link or bad connection at the junction block would be the first things to check for.