1990 EF Civic SI - Full B18C Swap with intake and exhaust, done by a professional Honda shop. Car has very little problems and has been running fine for years.

Tachometer is showing zero when idling, Car is idling normally, and the tach works fine when giving any gas or driving.

I have taken off the Dizzy, opened it up, all wiring is good, ICM was recently replaced with a genuine acura part so I know it's not that.

Does anyone know where I should be looking inside the car? Do I need to take the whole dashboard off? or is there a way to just remove the gauge "shroud" tho check wiring there?

If anyone has ANY advice I would greatly appreciate it.

TLDR: Tach showing zero at idle, Works normally otherwise, All wiring at dizy checked and ICM is good. Need advice where else to look.

Thanks

 

My guess is the tach itself is bad or possible the diel needs to be moved on pin. 94

 

I had the same problem, I removed the cluster and swapped out the tachometer portion. The old one was broken, the new one worked perfectly.

 

I would start by moving the dial, pull dial off pin and reinstall it a 0, [not all the way to the bottom] if it still does the same replace the tach/cluster. 94