there are many threads on this, but every one seems to have a 91 (vss) or some modified msd or 350 motor swap.

This is for a completely stock 86 iroc: I started this car after sitting for 4 years- it runs and all other gauges work- the TACH IS WACKY. All over the place.

I read about the tach being shot, and replacing that capacitor thing-but

I already have another complete 140/5500-rpm cluster. But I would like to check wires that provide the signal for the tach before taking it out.

From what I read on the wires, they go to the distributer?- anyone know wich ones they are? I have a feeling they might be corroded and may just need to be cleaned.

Thanks

 

White wire from your coil runs straight to the distributor. I would check between that point and the PCB connection behind your cluster for a solid connectivity.

 

I Rebuilt my 305 CFI and threw it back in and now i don't have a working tach at all. i checked the power from the tach mark on the coil and it has power but when it comes back around from the other end of the tach filter i have no power. also when the cars running it doesn't pulsate at the coil. do you know my problem?

 

since it worked before you pulled the motor, its most likely something you missed- I would get the manual-chiltons or whatever- find the wiring diagram and follow each lead until you find wich one you messed up on. I think there are only two running off the distributer-idk 82 cfi is different than an 86. My problem was the tach itself-

 

My tach used to be just fine on my 86 iroc, but ever since I replaced all of the belts the tachometer bounces and is off by quite a bit- in fact when I barely rev the engine it goes straight to 7000rpm. Can anyone tell me what to do or what to check and where the power comes from? Greatly appreciated.

 

Could it be a bad ground? My '84 Firebird S/E is having the same issue, though it seems to be related to the other electronics, as when I use the signal lights, the tach moves with it. My other electroncs don't all work either, at least properly. I'm working on tracking down what it is, lots of other guys have said that it is probably a bad ground.

 

How do I fix my ground? I'm still new to my car

 

I haven't managed to get it fixed on my car yet, but one of the guys I correspond with sent me this for checking my ground.



Hopefully that helps you out.