Hey guys,

My 89 IROC is having an issue with the tach. It reads double what the RPMS really are. Stock 5.0 TPI engine, stock distributor, stock tach, the problem started recently. I have owned the car for 12 years and the only part I have replaced that might effect this is the hypertech chip, but I put that in several years ago, in fact I have tried the factory chip to see if that fixed it and it made no difference.

Any ideas? Anybody else ever run into this?
Thanks

 

I've read about this on the internet, since the same thing happens to my '91 Camaro RS. Apparently, Third Generation Camaros have a problem with tachometers. I don't know about you, but I'm going to get a racing tachometer and override the one I've got now. Screw it.

 

Yep, so did my 91 read double. And so did another guys car...and another guys car...and...
A mis-reading tach seems to be a big epidemic with this model. I just did the math when I drove. Hey, it keeps the mind sharp!

 

its a common issue. i dont know if it was the tach itself or something in the wiring though as my stock gauges stopped working after a hard launch one day

 

Luckily ive never had a problem with my tach, though they are pretty inacurate to begin with

try an aftermarket tach, if it fix's your problem then you can buy another stock tach to throw in your cluster, if you want a stock look

i had a problem with my temp gauge, it would read full hot when it was only around 190 degrees, i popped the old one out, plugged a new one in and the problem was fixed, even unplugged my temp gauge would read around 220 and if i phisically moved it down to 0 it would move right back to 220

 

i have a double set of gauges if you want to try another tach. pm me if you are interested

 

yes the third gen tach. is pretty bad (we have aftermarket one along with oil gauge)

 

katzen did it fix the problem??

 

Have you tried replacing the tach filter? It is located about the center of the firewall, looks like a condensor with a wire coming out frome each end. When that goes bad the tach will read wrong or bounce, or quit altogether. I just replaced mine to correct mine. Cost and availability are a problem. I found a new one that worked for me from a seller on ebay earlier this summer.

 

Black89rs no its mounted not the actual tach. its above the air and radio