M30 swap questions..trying to finish this thing up!

[tfritz]

I am currently trying to connect all the plugs from the harness to the motor and have run into some issues.

Motor is a b35 and I am using an m30 harness. I can not seem to find a wire for the starter, I have the main power cable on the e30 which has the one wire for the starter but I cannot figure out what to use for the other...

Next question, for now, where is the plug for the O2 sensor and what does it look like?

Thanks!

[tfritz]

Okay, I think I figured it all out except the O2 sensor and the starter wire..... I believe the harness im using is a b35 harness, (plugs right into e30 body harness), does it not have an O2 sensor?

[tfritz]

nobody??

[WatchMyDrift]

Im almost positive the c101 port on the m30b35 will not fit the e30 plug. what year e30?

I actually used the harness from my m20, its like my car doesnt even know i swaped motors lol.

as for the o2 sensor it should be a small round twist in plug. I used my o2 sensor from my m20. I think the o2 plug is in the part of the harness that goes under the intake manifold

some one correct me if im wrong

[tfritz]

Car is a 1990. I have the m20 harness but would rather use the m30 harness. I will post some pics tomorrow, but there does not appear to be any o2 plug on my m30 harness.... And also just cant figure out the starter wires..

[WatchMyDrift]

wierd... i have a 90 m30 and a 91 e30 and i know for sure my m30 harness wont plug in to the e30 c101.....

[WatchMyDrift]

as far as the starter cable. the harnes should be right there next to the starter. 1 heavy guage wire that hooks in the center and 2 small wires that hook up on the bottom and top of the starter solinoid

[tfritz]

Just did lots of searching and reading and I believe the m30 harness I have is from a car with SLS. So I think that explains the o2 plug, but I still dont know about the starter wires. I have another m30 harness but it has been spliced to run in my brothers m30 swapped 525i, and that harness has the starter wires where I would expect them.

[yert315]

B35 harness will plug right in to late model e30s.

The o2 sensor plug is under the intake IIRC.
Starter wiring:
Do you have the wire harness that runs from the alternator to the starter (bolts on the block under the intake)?

[tfritz]

Okay here are some pics..

Harness im trying to use...and now that I think about it, I believe this harness may be from a 735i auto...

I believe this round plug with the yellow holder attached is the o2 sensor plug...and you can also see that there are no wires for the starter like there is in the next pic..



Also wondering where the wires in this pic go. Red wire go to power? And the two black ones to the left go to ground?

And are any of these smaller plugs needed?

[tfritz]

Oh, and I do have the harness bolted on the motor from the alternator to the starter

[tfritz]

Okay, so I cut up some of the black cover where the starter wires should be and found a wire cut off in there. The wire is black with yellow stripe which matches one of the starter wires on my other m30 harness. But this is the only wire in there, the other harness has another wire to the starter (black with green stripe), there is no such wire in the harness im trying to use...

[mini612]

I'm also running into some issues with my harness as well. m30b34 into an e30. the previous-previous owner used a different harness and ecu to do a 2.3head + 2.7bottom swap. I can't seem to find the round c101 plug that everyones been talking about, instead I see a rectanglaurish black plug that plugs into the fire wall holding 5 or 6 wires. There's also another plug that is attached to the fuse box.

[csermonet47]

Is your M20 harness undamaged? I would highly suggest using it. Will end up much cleaner than using an M30 harness. You can cut up the injector box and make everything fit nice:



All the plugs match up perfectly. Just need to lengthen one or two wires. And it fits the E30 bay much better since it is factory.

[Good & Tight]

That's a great looking swap, what position did you use on the engine brackets?