Hello Billy,

Thank you for your reply.

Yes, this truck originally had this kind of sensor. A strange one.

Actually the old sensor and the new one has 4 wire as well. But we have not calibrated the truck. We do not have a program for it.

So I guess this could be the problem. It is just seems to be strange that this tachometer could casued a sympthom like this.


Anyway, thank you again.