Hello,

I am building a xr4i sprintex and want to use a cosworth tacho because of the boost meter. The tuner can make change the 6 pulse to a 4 pulse to work with the cosworth tacho.

But are these clusters interchangable? without changing the connector. I don´t wont to short circuit anything.
Also does the tacho react to a negative or positive pulse? Also kind of curious what the red wire does.


here some pics:

 

Negative, there is a circuit that runs the electronics, so red is a switched live.

Yellow is a trigger input to the IC, which drives the motor.

I recently diagnosed/replaced the former for someone.

As to the interchange question, the connectors are different between MK1 and 2, but imagine they are the same on MK1?

Martin

 

I get it. The red wire is there because they have cut out some of the print circuit. It fits right in the mk1 cluster.

thanks!