I just installed a fresh LS1, and now my tach is not working. The car starts and runs well, but the tach sits right on the needle below 0 RPM and does not move. All other gauges work, except the speedo is pegged to the far right. Oil PSI, fuel, water temp, and voltage are all reading correctly. It should be noted that i completely demolished the #7 piston, could that have damaged the cam sensor? The car runs and starts perfectly. I am thinking it may be a cluster issue, even though I have never had the cluster out or apart. Thanks.

 

What year is your car? Is the fuel level gauge working?

 

if the fuel level gauge isnt working, has to do with serial data link

 

Fuel level gauge is working. I wonder if just one of the contacts is bad on the cmp sensor.

 

TTT, both the tach and speedo move just a hair when the key is turned on. But they do not move after the engine is running.

 

ya the gauges will move a lil just because they are getting power but no serial data signal. happened to me because my serial data wire was cut somehow

 

Well, the speedometer doesn't use the serial data signal, it recieves from the vss output of the ecm. That is what has me puzzled. Seems like the cluster may have a problem.

 

oh ya, duh. i missed the word speedometer in the post. just now realized also said fuel gauge does work. my head is going 100mph today

 

I will have to inspect everything when I pull it apart to install a TA bezel. The car lost the piston at about 100 MPH and killed the engine immediately, the speedo fell all the way to the right when it happened.