2G 2G Bouncing Tach

[wishihadatalon]

Alright guys, I did a search on here but I didn't see anyone with the same issue I was having so I figured I would start a new thread.

Lately my tach has been bouncing when I start the car. It goes all over the place and I can't seem to figure it out. I am having no other issues with the car but that could be because I have a MegaSquirt ECU in the car.

The MegaSquirt ECU gets its tach signal from the CAS and the signal to that is perfect. So my question is where does the 2g tach get its signal from? I assume its the PTU but I figured I would verify.

Also has anyone ever just had the tach in the cluster go bad?

 

[MiroDSM]

Power transistor I think it's called. Once had a heater core coolant line bust and it wet that item and my rpm would jump all over the place and then stopped working. I set it out to dry and it worked again. So yes I would check your PTU.