Tach at 7000
Thread Starter
Instructor
Joined: Aug 2005
Posts: 237
Likes: 1
From: Lake Stevens Wa
Tach at 7000
Im new to Corvettes still, Just picked up a 75 with 90k on it yesterday. Its got a few problems, but was worth the $4000. I believe that I read on here that 75 and earlier had the mech tachs. My problem is that my tach is constantly at 7000 rpm, even when its shut down, rev it up and it moves only a little. Any Ideas?
Burning Brakes
Joined: Jun 2005
Posts: 764
Likes: 2
From: THE OLDER I GET THE BETTER I WAS! NORTHERN ONTARIO
There is a tach filter tha is supposed to go between the distributor & the tach wire, it looks like a noise suppression cap but it is designed to eliminate spikes that whack your tach! This could be the priblem...all the aftermarket corvette suppliers have them 
oh yeah...about $50
oh yeah...about $50
Thread Starter
Instructor
Joined: Aug 2005
Posts: 237
Likes: 1
From: Lake Stevens Wa
Originally Posted by G dad
There is a tach filter tha is supposed to go between the distributor & the tach wire, it looks like a noise suppression cap but it is designed to eliminate spikes that whack your tach! This could be the priblem...all the aftermarket corvette suppliers have them oh yeah...about $50
oh yeah...about $50I think I remember reading about that a few days ago, Thats the thing with the little gear that bolts to the dist.
I'll try to check both those things out tomarrow.
Thanks
Racer
Joined: Jul 2005
Posts: 499
Likes: 1
From: Winnipeg Manitoba
Originally Posted by G dad
it looks like a noise suppression cap but it is designed to eliminate spikes that whack your tach! This could be the problem...
If the tach was working properly and the filter was open or shorted, the reading would go to 0 RPM.
Since yours is always reading 7000 - I would say your tach is most likely dead.
Battery reversal will instantly kill some of the early electronic tachs (75, 76). If it has a burnt out trace, you might be able to fix it.
