No Tach

[aminga]

After my rebuild the factory tach and my aftermarket are both not reading. Scanmaster has a valid RMP signal.

 

[getdowngranny]

I have the same issue. Ive traced it down to a bad tach output of the ignition control module. I havent been able to get my hands on a good one yet. Ive been to the junkyard twice and the ones i pulled were not working. Im waiting on the Bob Bailey module and coil pack to come out.

 

[aminga]

SO to close the loop on this in case anyone does a search and runs across this.

The aftermarket tach was wired backwards + and - reversed. I thought I unplugged the aftermarket tach under the hood but maybe I didn't.