91 318is m30 swap

[jon5226]

So far i have taken out the m42, and now im cleaning up the engine bay and collecting hopefully the last couple parts i will need to make this work.

pics will be up soon.

so i have a 91 318is, and a m20 wiring harness and a m30 3.5 (with no harness),

1. Im trying to figure out whether its worth it to buy a m30 harness or try to make what i have work?

2. Either way i think i will need some c101 plug diagrams, can anyone point me in the right direction for what i have? or with m30 harness?

3. which wires am i going to have to splice together to get this to work?

Any advice or input at all will be appreciated thanks.

[browntown]

Late model 325i harness should hook up just fine but you may have to lengthen a couple wires. Wedophones has all the electrical handbooks. Use search here to find even more detail. When you freshen up your m30, hook up the harness you have on an engine stand and see what you have to lengthen. They're almost the same motor, the m30 is bigger.

[yert315]

I would recommend buying a b35 harness. Two reasons:
1) it looks MUCH cleaner
2) it is literally Plug and play

[jon5226]

plug and play at the c101 plug on the 318is?

[Lurker27]

I would recommend buying a b35 harness. Two reasons:
1) it looks MUCH cleaner
2) it is literally Plug and play

Only if pre 1991

[lashtx]

plug and play at the c101 plug on the 318is?

I did the swap in a 1991 318i. It was plug and play with the '89 B35 harness with the exception of having to move one wire and loop another.

Kris

[jon5226]

well, ive started to plug the m20 harness to the m30 and haven't had to lengthen anything YET. fuel injectors and thermostat wires fit fine but i think i will be lengthening the starter, altenator, and crank shaft position wires.

At the c101 plug all the pins line up but there is 3 unused contacts on the 318is side of the plug.....Has anyone used this setup? or know what those unused contacts might be?

We will be positioning the engine in the car hopefullyy in the next couple days so i ges i will find out if those contacts are important.

any advice in the mean time will be appreciated.

[jon5226]

im having a hard time distinguishing the starter and altenator wires apart.

just from the lengths and whats in the neighborhood of these wires is all i have as a reference. every wire diagram ive been refered to is in german or unreadable

and i dont know what wedophones is?

[jon5226]

wedophones had mostly chassis wire diagrams and some fuel inj diagrams.

but i know my wires now (i hope) looks like i need to add length to altenator, crank position sensor, and starter wires.

just worried about whats gona happen at the c101 plug.

only thing holding me up from fitting engine in car is power steering. i need the 8 bolt pulley that bolts to crank and i need the pump brackets that bolt to the block.

can anyone help?