NJ-JDM

iTrader: (23)

Short history. Bought my 93 in Nov. Original cluster was not installed, said to have a bad tach and odometer was not working. I wanted to preserve the mileage etc so I sent it out to be 'fixed'.

Cluster that was in the car, the tach worked some of the time. So once I got the original back I put it in. The speedo place replaced 10-12 caps across the cluster and assured me that the tach was working. Well, it exhibits the same behavior as the first cluster, it works almost none of the time. So I figure maybe its the cars harness. I run a jumper for the signal wire. Same thing, intermittent. This weekend, I run two more jumpers for the ground and power. Same thing, it barely works. Freaking PITA.

Questions:
Is there a pin/lead off of the ECM that is used for the tach signal? I am thinking of testing the conductivity from the dash back to the ECM.

Is the factory tach accurate? Reason I ask, for the few minutes it was working, I looked at the PFC commander RPM and it was off by 400 from the dash. I have to assume that the PFC is the more accurate number.

I was traveling at 76-78 MPH, in 5th. Commander was btw 3100-3200. The dash indicated 3600.

Thanks for any info.

DaleClark

iTrader: (55)

Get a good used JDM cluster, move your speedo chip into it, done. Or, if the speedo is working fine, just get the tach out of the cluster (it attaches with 3 screws) and done.

9 times out of 10, it's the tach itself. I seriously doubt it's grounds or wiring or anything.

Dale