91 Tachometer ?
Thread Starter
Max G’s
Joined: Nov 2008
Posts: 2,751
Likes: 79
From: Monroe OH
NCM Sinkhole Donor
91 Tachometer ?
Wanted to see if someone knew before I had to search in the service manual on tachometer. Drove the 91 stock car yesterday and the tach started to bounce when in higher rpm range @3000 and up. Is the connection to the tach on the dash an electronic or mechanical connection? Thanks for any info.
Le Mans Master
Joined: Aug 2000
Posts: 8,838
Likes: 31
From: Australia
Most likely faulty tacho in dash ; common 90/91 problem
http://forums.corvetteforum.com/c4-g...ch-filter.html
http://www.thirdgen.org/techboard/el...meter-fix.html
http://forums.corvetteforum.com/c4-g...1990-vert.html
http://forums.corvetteforum.com/c4-g...ch-repair.html
Racer
Joined: Jul 2007
Posts: 379
Likes: 12
From: Huntsvegas AL
Mine does the same thing, tach needle goes batsh1t crazy about 2500 - 3000 RPMs. Pretty much useless at that point, but being I have a slushbox, not a big deal.
As an added bonus, my oil temp gauge always reads low. Ive replaced the sender, Ive verified that wiring is good, I wonder, does the oil temp circuit have a similar arrangement as the tach circuit, and theres a resistor that needs attention?
As an added bonus, my oil temp gauge always reads low. Ive replaced the sender, Ive verified that wiring is good, I wonder, does the oil temp circuit have a similar arrangement as the tach circuit, and theres a resistor that needs attention?
Thread Starter
Max G’s
Joined: Nov 2008
Posts: 2,751
Likes: 79
From: Monroe OH
NCM Sinkhole Donor
All electronic
Most likely faulty tacho in dash ; common 90/91 problem
http://forums.corvetteforum.com/c4-g...ch-filter.html
http://www.thirdgen.org/techboard/el...meter-fix.html
http://forums.corvetteforum.com/c4-g...1990-vert.html
http://forums.corvetteforum.com/c4-g...ch-repair.html
Most likely faulty tacho in dash ; common 90/91 problem
http://forums.corvetteforum.com/c4-g...ch-filter.html
http://www.thirdgen.org/techboard/el...meter-fix.html
http://forums.corvetteforum.com/c4-g...1990-vert.html
http://forums.corvetteforum.com/c4-g...ch-repair.html
Thread Starter
Max G’s
Joined: Nov 2008
Posts: 2,751
Likes: 79
From: Monroe OH
NCM Sinkhole Donor
[QUOTE=Gear Jammer;1576670354]Mine does the same thing, tach needle goes batsh1t crazy about 2500 - 3000 RPMs. Pretty much useless at that point, but being I have a slushbox, not a big deal.
What is a slushbox?
What is a slushbox?
Le Mans Master
Joined: Aug 2000
Posts: 8,838
Likes: 31
From: Australia
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Racer
Joined: Jul 2007
Posts: 379
Likes: 12
From: Huntsvegas AL
Me being a wannabe old-skool gearhead. <Or as previously stated, an automatic trans> 
Once I get sone of my other projects outta the way, Im going to tackle the tach, soldering in a new resistor shouldnt be too much trouble (ha ha famous last words I know)...
On the referenced threads, there seems to be an unsettled debate as to whether the 91 needs a 300k resistor.
john
Once I get sone of my other projects outta the way, Im going to tackle the tach, soldering in a new resistor shouldnt be too much trouble (ha ha famous last words I know)...
On the referenced threads, there seems to be an unsettled debate as to whether the 91 needs a 300k resistor.
john
Thread Starter
Max G’s
Joined: Nov 2008
Posts: 2,751
Likes: 79
From: Monroe OH
NCM Sinkhole Donor
