Doing a diesel swap. Need some advise.

Finally, a home for all you 524td oil burners out there.
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Posts: 3
Joined: Dec 31, 2018 12:09 PM
Location: California

Doing a diesel swap. Need some advise.

Post by BavBum »

I'm getting ready to take on doing an m21 swap into an e30. I have an entire 1985 524td parts car. Currently I'm hung up on the wiring harness. My thought is to use an e30 TD wiring harness, but I can only find one from a later model e30 with the electric fuel pump. I also have the complete e28 harness.

1: Will an e30 harness with electric fuel pump work on a motor without it?

2: Can the e28 harness work in an e30?

3: should I just keep shopping for the correct harness?

Any advise is appreciated.
Posts: 573
Joined: Nov 22, 2017 11:30 PM
Location: New Jersey

Re: Doing a diesel swap. Need some advise.

Post by gadget73 »

If this is from a 324td, those are the Euro version with the non-electronic injection pump. If your donor car is a US spec, thats got the injection pump that requires a computer. Not sure if you can swap harnesses if there isn't any provision for the timing control. If yours is running a Euro injection pump, there isn't any timing control. Should be just the fuel cutoff solenoid and a cold start timing advance solenoid that wires to a thermal switch on the side of the head.

Is that the electric pump you mean, or does this also have an electric low pressure fuel pump ahead of the injection pump?
Posts: 75
Joined: Sep 30, 2010 9:46 PM
Location: Tangent, OR

Re: Doing a diesel swap. Need some advise.

Post by LuckyHenriksen »

I have also been curious about this, as I am making plans to swap an M21 into a different chassis. I was hoping that I could just eliminate most of the wiring harness to simplify things. I am wondering if the engine will run without the computer control unit and the injector with the sensor wire in it. Maybe I need to source a "euro" injection pump to eliminate the computer control. I will keep an eye on this thread and see what kind of info others share.
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