b34 Wiring Help

[porschelou]

Hello,
We are doing our first swap and will be ready to drop the rebuilt motor in next week. I pulled the motor / trans / harness from one of my 87 e28 parts cars. I will be using the b34 harness and not the b35. We are on a tight time line to get the car running - we have to race it on May 20th.

A few questions about wiring it up -
1. Since this harness doesn't have the round connector like the m20 harness do I pull the required signals for the dash from the ECU wiring (ie cut the b34 harness and get the signals)?
2. I have read that you can use he m20 harness just extend the wiring to the required sensors ? True or Un-True (the e30 is a 86 325e)
3. I have Franks 65pages instruction sheets but it just briefly talks about the b34 harness.
4. Do I leave the e30 dash in it or plug in the e28 dash??

Does anyone have first hand knowledge about the b34 wiring. I realize the b35 would be easier but I have 3 free 535is cars so free is better then easier.

Thanks
Can't wait to get the sucker running - our e30 is fully stripped race body with a cage. We have made it as light as possible so with roughly 200hp it should be fun...

[Jean]

Are you trying to use b34 harness on m30b34 or m30b35?

[Jean]

Convert the chassis side or engine side plug or make adapter regarding c101

[bmwmech1]

If the E30 is an 86, it won't have a C101 connector, it's to early of a chassis. Hardwiring is probably going to be the solution, although you would know more firsthand Jean...

Garey

[The Humjet]

I could answer your question 2 by saying yes you can use the m20 harness from a plastic bumpered e30 so not your 86 325e harness you need one from a late motronic ecu such as 320i or 325i I'm not sure about the super eta harnesses for you guys in the states

[porschelou]

Thanks for the replies. We are putting in a b34 motor with it's factory wiring harness. The e30 must be a late model since it has the round c101 connector by the fuse box. I think I figured it out. I'm going to cut off the male portion of the C101 from the m20 engine harness and solder it on to the b34 engine harness. This should allow almost a plug / play setup. There are three wires near the ecu connector that needs to be connected as well (tach,fuel consumption).

Just one question -can I just install the dash display out of the e28 so the tach will be correct??

We are shooting to have this running by May 6th so we can take it to the local drag strip. Only place to test it our since it's not street legal.

Thanks for the help!!