So I started car up and my RPM gauge won't move from is rest spot on the needle stopper thing. The car seems to be running a bit rough, any thoughts?

 

Are you sure its running. J/K
The tach works via the pcm so do you have any ses lights. If so get the car scanned and come back with the codes.

 

edit I see you have an msd box, try to bypass it and see if it runs any better or if the rpm gauge works. Have you ever had any problems with it

 

yea, it's been running good, just like all of the sudden sometimes it shuts off when I first start it and it gets warm.

 

Loose wire somewhere I bet. seems to be the reaccuring problem with any of the cars I use with a Tach

 

Check the connections on your coil and ICM. I believe the PCM pulls the tach signal from the coil, but don't quote me on that.

 

i think the bottom left spark plug wire on the optispark (facing front of engine) could be loose, how can i plug it all the way in? so hard to even squeeze my fingers in there

 

Not sure.. But that would not cause a dead tach, that could just cause a miss, that you would see on the tach

 

The PCM reads the RPM from the optical sensor in the Opti.

 

so either theres a wiring problem from opti to pcm or my opti is failing?

 

Not likely. If you weren't getting the pulse signals from the Opti, the engine would either run poorly, or not run at all. It sounds like you have a problem between the PCM and the tach. Or the tach connections in the cluster are bad, or the tach is deceased.

There is a white wire that runs from pin A13 (red connector) on the PCM, through a harness connector (C230, pin D on the 95's, per Shoebox's wiring diagrams, may be different on your 94) and into the cluster. Check that wire for a signal. If you could put a frequency meter on it, you should be able to pick up the pulse rate to the tach. If the wire has the signal, it would indicate a tach problem.

I think the only year that takes the tach signal off the coil is the 93's.

 

Well, i started it today and and the rpm gauge was sitting at 0 for about 10seconds, then all of the sudden the rpms gauge started working again. Also while I was driving the car just shut off while I was idling around a turn.

 

Old post but I give it a try. I have the same problem. Did you manage to solve this issue and what was the problem?

 

Original poster hasn’t signed into this site since 2010.

I assume your “same problem” is the tachometer not working. Does your engine also shut off at random times? What year is your LT1?

For anyone trying to help, please respond in this thread:

https://www.camaroz28.com/forums/lt1...-drive-889752/

 

[QUOTE=Injuneer;7016253]I assume your “same problem” is the tachometer not working. Does your engine also shut off at random times? What year is your LT1?

The engine is a 1997 5,7 l (Z28).

Yes, the engine also shut off at random times. Then I press the clutch (manual 6-speed) and pimp on the gas engines start again but sometimes the tach is at zero for minutes before it starts working again. Have had this issue on and off for two years by know and really want to solve it. Hope you or someone else can help! No luck so far on finding a answer.