Just at idle my rpm output to the tachometer will read 0 but the car is running and idling fine. It doesn't do this at every idling situation. My question is what controls the rpm output that is sent to the tachometer? Is it just the distributor? What may be causing this problem? IACM?

 

check ur dizzy. there is a blue/yellow wire that is rpm signal

 

the wire is solid blue and is in the 2-wire connector

 

ok yea on my dizzy its a 2 pin blue/yellow wire

 

Your talking about the stock tach in the inst cluster right.?

Mine does the same thing...I think its the tach itself that is faulty. Works great except at warm idle it sits at the bottom.

 

yeah it is the stock tach, but I also have a rywire kit with a distributor connector. Should I also check the back of the tach itself for a bad connection or is it not related?