BMW M42 swap into 76 2002 Tach connections for Tach Adapter

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tashakes
Posts: 2
Joined: Mon Nov 17, 2014 6:45 pm
Location: United States

BMW M42 swap into 76 2002 Tach connections for Tach Adapter

Post by tashakes »

Hello. I have purchased a tach adapter (http://www.autosportlabs.com/product/tach-adapter/) and just wanted to know what is the best way to make the connections. I have a 1991 M42 engine swapped into a 1976 2002 with an analog tach that was connected to the coil on the original engine.

On the new M42 there is a 5V square wave signal coming from the C101 connector that can be used, I tried it with a MSD tach adapter but ended up frying it cause I pretty much had no idea what I was doing.

Before frying this one, what is the best way to connect the adapter? I have read that since there are 4 coils on the M42 I can connect one terminal to each, but I also read that 2 coils fire at the same time (not sure why or how), so I am not sure that connecting 1-2-3-4 will work. Also, is there a way to use the ECU signal from the C101 connector?

TIA for any help on this.

tashakes
Posts: 2
Joined: Mon Nov 17, 2014 6:45 pm
Location: United States

Post by tashakes »

Just posting my own reply. Tach wire on the 2002 goes to tach output from the adapter, coil 1 goes to c101 tach output from ECU.

sbarton
Posts: 94
Joined: Mon Mar 11, 2013 5:45 pm
Location: NJ
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Post by sbarton »

I did this swap. Let me know if need anything.

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