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3-wire COP seup on 1990 4-wire Coilpack

Hey everyone,
just as the subject say, I need information on how to install a 3-wire COP setup on my 1990 4-wire coilpack.
Is there a diagram somewhere on how to connect the wires properly and do not lose tach signal ..
thanks in advance


Well-known member
May 4, 2003
Clarksville TN
I'll look around on my desk. I have a print out of something that was posted on dsm tuners

The white wire is the tach wire (pin #3), the heavy black/white striped wire is the +12 volts (pin #4). The Yellow/Green striped wire and the Yellow/Black striped wire are the two wires from the transitor to drive the coils (pins 2 &1).

I am confused now!
according to diagram, I should connect the tach signal to YG/YB with an OR circuit/ yep?
How to do that? what is an OR circuit?

That is the "tach driver" module that is attached to your 1990 coilpack. You will need to move the tach driver to the COP if you expect to have tach signals to the ECU and dash tach.

You mean the OR Circuit is the "tach driver"? and I should relocate it to cop setup?
sorry for the lack of electrical knowledge..

Yes, the "tach driver" module, which is shown in the diagram as an OR circuit, needs to be moved to the COP setup if you want tach pulses.
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