M20 E to I turbo question

[SkywayScraper]

I just finished changing my 87 eta to a I motor and about 95% complete on the turbo project. Since I have changed the wiring harness to the I motor harness, I keep popping one fuse. Its the one that runs the fuel gauge and tach and coolant gauge along with the blower motor for the heat. I havent been able to trace down a short.

Does anyone know what the problem might be?

[jlevie]

The only way I can think of for the harness change to be involved would be if there was a short in the harness that involved the oil pressure switch or coolant temp sensor. If you disconnect C101 does the fuse still blow? If it does, the problem is on the body side and you can use the wiring diagrams from http://wedophones.com/BMWManualsLead.htm to find it.

[Me+SPEED=]

Fuses normally blow because of short to ground. You can try disconnecting everything on that circut and then plug them back in one at a time untill the fuse pops. Probley going to have to trace a lot of wires.

[SkywayScraper]

So I unplugged the c101 plug and the fuse didnt blow
im guessing the short is on the motor harness.

[jlevie]

So I unplugged the c101 plug and the fuse didnt blow
im guessing the short is on the motor harness.

Yep!

[SkywayScraper]

So were should I start I remember there was one wire that i had to cut on that c101 plug to get the car started?

[jlevie]

So were should I start I remember there was one wire that i had to cut on that c101 plug to get the car started?

You don't say what year harness you have, but if from a car built from 9/87 on, reconnect C101 and disconnect C191. The will tell which part of the harness is bad. Then it will be a matter of removing the harness from the car, cutting it open, and repairing the damage. Or, you could get another harness and hope it is better.

As an FYI: I have three used harnesses each of which developed an internal problem while on the race car engine. I got tired of that nonsense and bought a brand new harness from BMW. It should be good for another 20 years.

[SkywayScraper]

I am pretty sure that the harness I have now is out of an 88 super eta?

[jlevie]

With respect to this fuse I don't think it matters whether this harness is from a SuperETA or an M20B25.

[SkywayScraper]

I was wrong from my previous post. So I unplugged the c101 plug and the fuse still popped so the short is somewhere in the body harness.