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Oops thats a lot of questions.

Very important is that the fuel pump relay is switched by the ECU.
Pump must shut off when the engine stalls.

Seems like a good idea to hook the relais up then!
Do you know how the wiring goes? What color goes to the pump?

I'll gues your ecu is motronic, i do not know the motronic wire colors, but there will be plenty information about it on the interweb.

In the E12 wiring loom the fuel pump wire is purple with green band. (If it is already in)

BertjeConti wrote:In the E12 wiring loom the fuel pump wire is purple with green band. (If it is already in)

thanks, its not in yet, but I think I know how to connect the fuelpump:



the E34 cables are pretty much the same colors. also the green/violet goes to the fuel pump.
There are 2 of these cables coming out of the same connector in the fuelpump relais, so I recon that one will go to the pump and the other to the fuse box, am I correct? Or do I need to make a fuse on the cable to the fuelpump?

I've used that same orange relay, in my case it was taken from a E30 motronic.

Because this "fuel pump" relay is an external relay (out of the fuse box) the fuse is placed before the relay contact (in the fusebox) switched by the main relay.

This fuel pump relay has 2 contacts with 2 green/purple wires, one goes to the fuel pump and the other goes to the fuel injectors, the injectors need some juice too.

This is my E12 fusebox / relays setup:



beware, i did not use the BMW correct wire colours.
in my case the fuelpump wire (purple/green) was already in the wiring loom of the car, it goes from the fuelpump relay back through the fusebox, which is a little confusing.

thank you for this!

so if i'm right:

from the fuelpump there goes a cable to the fusebox. I need to connect a wire to this fuse.
the earth cable of the fuelpump can be connected on the car itself.
from the fusebox I need to connect one of the 2 violet/green wires to the fuelpump relais, the other violet/green wire goes to the injectors.

Sounds ok to me

BertjeConti wrote:Sounds ok to me

thanks! As soon as we have an update we will let you know

one extra question though.
The car originally doesn't have an electrical fuel-pump. But what is the color of the cable from the pump to the fusebox?
I recon it goes through the connectors under the steering wheel (see photo) does anybody have a layout of these connectors?
hopefully I can connect the wire from the pump to one of these connectors and is the wire from there to the fusebox already present.
(later we're also hooking up electrical windows + central locking, so it would be handy to know where to connect them under the steeringwheel as well)

1.5mm2, Wire color is Green/Violet (green with violet line), runs from fusebox (engine connector, sideways of fusebox) through the black connectorblock under the dash (middle box on your photo above), and from there in the wiring loom to the back of the car, under back seat the fuelpump wire splits from the main loom and runs under the seat to the other side of the car to the fuelpump. Wire is all the way green with violet line.

In the black connector box under dash the green/violet wire is situated next to the green/yellow wire (upper right), in your case a empty spot. other colors in that connector are violet/white, violet/black, black/red, grey/yellow, green/yellow if i'm not mistaken.

Thanks again! This is very helpfull
I just reminded that we have all the wiring of a type 2 e12 528i. So i will use that wiring loom in the car.
I think i will open the fusebox to see if the fuel pump fuse is connected. Hopefully it allready runs to the black connector under the steering wheel.

Is there a layout of the connectors under the steeringwheel?

Yoozt wrote:Thanks again! This is very helpfull
I just reminded that we have all the wiring of a type 2 e12 528i. So i will use that wiring loom in the car.
I think i will open the fusebox to see if the fuel pump fuse is connected. Hopefully it allready runs to the black connector under the steering wheel.

Is there a layout of the connectors under the steeringwheel?

Yes there is, i have them, only not digital (yet)
i'll scan them next week and post them here

great! thank you in advance

here they are, from the manual which came with the car, it's in Germain.



link to the original size: E12 Schaltplan

injection:


also a link to the full size version: E12 Schaltplan einspritzung

central lock:


and again a link to the full size image: E12 Schaltplan zentralverrieglung