S1 Fuel pump wiring question

[SteveJB]

Fuel pump appears to have packed in but thought I'd check the electrics before changing it.

There is a 4 point plug with 2 black wires, 1 green & black wire and 1 green & orange wire. Any idea what each colour is and what each should be tested for?

Thanks

Steven

[robin]

I'll check for you in a minute, but normally the problem comes at the other end of the connection.

The fuel pump circuit runs through several loom connectors as well as its own fuse somewhere in the boot area (there's a hole cut in the passenger side boot wall and the fuse is in that hole, IIRC), the immobiliser "relay", the fuel pump relay (inside the MFRU) and the inertia switch.

If it "just stopped" then I would check the inertia switch to see if it has popped.

<edited to remove wrong advice>

I cannot remember all the details of colours and plugs, but if you tell me what car you have (I assume it's an S1, but what year?) I'll look at the wiring diagram and tell you which plugs/wire colours to check out.

Cheers,
Robin

[robin]

OK, so sequence is:

Battery -> Brown -> 10A fuel pump fuse (in boot) -> Purple -> Inertia switch -> White/Purple -> EHC2 -> White/Purple -> MFRU -> Brown/Grey -> EHC1 -> black -> Immob Relay -> black -> fuel pump harness connector -> Brown/Grey -> Fuel pump -> Black -> Earth.

So at the fuel pump connector the black wire should be connected to earth and the Brown/Grey wire should go live during priming but note that this only happens briefly during first ignition on sequence, so you may never spot it.

The other two wires are probably smaller gauge and these are the fuel level sensor wires.

If you remove the connector from the bottom of the inertia switch you should see permanent live on the purple wire, if not then you've got a problem with the fuse in all probability (they burn out the fuse holder and wires often due to permanent overheating).

Cheers,
Robin
Cheers,
Robin