Does the tach work off the cam or crank? I just put in a new LSX motor and the tach gauge does not work, so I'm wondering if I have a bad sensor or something else is wrong. Thanks

 

the tach runs off the cam sensor, check the ground from the engine block(behind the altnator) to the frame(driver side under the fuse boxes). also check the pins going into the pcm from the wiring harness. i would go over those first before you pull the intake off to change the cam sensor

 

I was throwing a P0336 code which is crankshaft sensor and my tach did not work. My wiring harness had hit my headers.

 

Good info! My tach fails to work sporadically and I've always blamed the wiring for my shift light and gauge overlay. I might need to check these other options.

 

I'll check them tomorrow and see if I can find the problem. Thanks for the information.