How do you wire up a fuel pump pllleeeaassee?

[rolls 912]

Hi again

Just finishing off the bosch fuel pump install for my '85 3.2 (in my 912)

Can anyone give me a clue as to how I should wire this puppy up?

• I assume I need a fuel pump relay? Should I use a generic one?
• It needs to be fused (located next to original fuse block)
• Which power source should I tap into?
• I read somewhere that it needs to go back to the DME but that doesn't sound right?

Any help at all would be hugely appreciated.

Cheers

Roland

[equality72521]

I read somewhere that it needs to go back to the DME but that doesn't sound right?

I believe that IS correct. Someone that knows Motronic better than me will chime in soon.

[Rot 911]

The relay for the DME (under the drives seat next to the DME) is also the fuel pump relay.

[Flat6pac]

And the answer is..
From the front of the wireing harness near the battery is a fuel pump wire. Where ever the fuse is for the fuel pump you will need to remove wire going into the fuse and replace it with the red/green wire. This powers the fuel pump but you need to wire the relay under the seat and that comes from the small black wire in the 3 or 4 wire group that has the tach drive.
I ll post a picture of the harness end showing what I m talking about.
Bruce

[Flat6pac]

[Flat6pac]

The small 4 wires in the picture. One small black will driive the relay, ohm the wire to see which one of the 2 does the job
The tach wire should jump to the tach, but not the 912 tach
The black wire next to the red/ green one is the coil wire. That wire NEEDS 12 volts all the time the key is on, even cranking, so you need to wire it into the safety emergency lights.
Bruce

[rolls 912]

Hey Bruce
If you are ever in Melbourne Australia the beers are on me!

Really appreciated

[rolls 912]

Hey Bruce

Another quick question - what are the two long green wires with the spade connectors for?

Thanks