Tach issue

[gsxeclipse97]

Ok i searched and i didnt find anything that quite same problem that has happen to me. Tonight i was driving around and did a couple of hard pulls, all of the sudden my tach started jumping around and then went flat to 0. While this would not be that big of an issue normally I also have a cyclone manifold and it needs an rpm signal to be functional. I noticed that there is no signal at all because the rpm switch also reads 0 and is plugged almost directly into the wiring harness.

So any thoughts here I also have a 1g cam sensor and 1g coil pack if that helps.

 

[luv2rallye]

Normally there is a ground strap on the stock intake mani to the firewall, so first see if yours is broken. The tach signal on all turbos (1g/2g) comes from the white wire on the power transistor (PT) (90's also have a tacho interface filter but no other years do). Check this wire for continuity to your tach or 2g ECU pin 58. Or perhaps the PT unit tach signal failed (you cannot test this other than swapping with another PT).

 

[gsxeclipse97]

are these interchangeable? for example could i use one from a 1g? or do i need to just pick one up from mitsu

 

[cardot33]

I'd check out the coil pack just make sure it's all connected. My Camaro did something similar to me before, then it wouldn't start up at all, I needed a new distributer and now it runs better than ever.