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View Full Version : Tach is off by about 200 rpms. Can I change this?


mvvette97
January 17th, 2009, 08:51 PM
I was looking at G1204 and G1205 but where do I start? When I'm idling at 800 the tach in the car reads about 1000 to 1100. Will changing these tables fix my problem?
nevinsb
January 18th, 2009, 05:15 AM
Were the needles removed from the gauges at all? Is it off by the same amount all the way up the RPM range?
mr.prick
January 18th, 2009, 06:04 AM
I was looking at G1204 and G1205 but where do I start? When I'm idling at 800 the tach in the car reads about 1000 to 1100. Will changing these tables fix my problem?

is this what you see while scanning? or are you using an aftermarket tach?
mvvette97
January 18th, 2009, 08:07 AM
It's the factory tach and yes the needle reads faster than what it really is when scanning with flashscan. I have never had the needles off since I have owned the car.
SOMhaveit
January 22nd, 2009, 03:19 PM
Mine's just the opposite and it is way off at higher RPM's. I think my tach is about -100 at idle and -600 at 6K Rpm's. When my tach says 6K it's really at least 6600. I wish we did have a way to adjust it.
GMPX
January 22nd, 2009, 05:54 PM
If it's off by that much over the entire range then the calibrations won't help. They are not 'trim' values as such. If the scantool is showing the correct RPM and the cluster is out by a 'bit', it's more than likely a cluster issue.

Cheers,
Ross
mvvette97
January 22nd, 2009, 05:58 PM
If it's off by that much over the entire range then the calibrations won't help. They are not 'trim' values as such. If the scantool is showing the correct RPM and the cluster is out by a 'bit', it's more than likely a cluster issue.

Cheers,
RossI was hoping I wouldn't hear that.:shock: I noticed that my volt gauge reads under also. It show like 12 volts but testing it with a meter it's almost 14 v. I looked on ebay and these clusters for the vettes are EXPENSIVE!