Tach reads to high after ECM replacement.
Thread Starter
Member
iTrader: (2)
Joined: Oct 2010
Posts: 199
Likes: 4
From: Des Moines, Iowa
Car: 1991 Camaro RS yellow
Engine: was '91 V6, now '89 5.7/355 TPI
Transmission: 4 speed automatic
Axle/Gears: Moser 3.73 with zexel posi
Tach reads to high after ECM replacement.
My tach was reading fine until I replaced my ECM, now it reads too high. Does ECM control voltage to the tach? What else could be wrong?
Joined: Dec 2004
Posts: 16,770
Likes: 1,001
From: Mile High Country !!!
Car: 1967 Camaro, 91 z28
Engine: Lb9
Transmission: M20
Axle/Gears: J65 pbr on stock posi 10bolt
Re: Tach reads to high after ECM replacement.
The tach feed is directly off the coil the ecm is unrelated.
Joined: Dec 2004
Posts: 16,770
Likes: 1,001
From: Mile High Country !!!
Car: 1967 Camaro, 91 z28
Engine: Lb9
Transmission: M20
Axle/Gears: J65 pbr on stock posi 10bolt
Re: Tach reads to high after ECM replacement.
There is a diy thread on the tach board fix 90-92 or you can get a new board.
https://www.thirdgen.org/forums/engi...achometer.html
https://www.thirdgen.org/forums/elec...meter-fix.html
https://www.thirdgen.org/forums/engi...achometer.html
https://www.thirdgen.org/forums/elec...meter-fix.html
Thread Starter
Member
iTrader: (2)
Joined: Oct 2010
Posts: 199
Likes: 4
From: Des Moines, Iowa
Car: 1991 Camaro RS yellow
Engine: was '91 V6, now '89 5.7/355 TPI
Transmission: 4 speed automatic
Axle/Gears: Moser 3.73 with zexel posi
Re: Tach reads to high after ECM replacement.
Thank you. I suppose a capacitor has failed.
Joined: Aug 2009
Posts: 1,821
Likes: 40
From: Central California
Car: 92 Camaro RS
Engine: LO3
Transmission: T5
Axle/Gears: stock
Re: Tach reads to high after ECM replacement.
You still have the V-6 tach or have you installed a new V-8 one?
Thread Starter
Member
iTrader: (2)
Joined: Oct 2010
Posts: 199
Likes: 4
From: Des Moines, Iowa
Car: 1991 Camaro RS yellow
Engine: was '91 V6, now '89 5.7/355 TPI
Transmission: 4 speed automatic
Axle/Gears: Moser 3.73 with zexel posi
Re: Tach reads to high after ECM replacement.
Can't tell. Cluster was a (140 mph) replacement from Canada. It worked til I replaced the ECM, but that's probably a co-incidence.
Joined: Aug 2009
Posts: 1,821
Likes: 40
From: Central California
Car: 92 Camaro RS
Engine: LO3
Transmission: T5
Axle/Gears: stock
Re: Tach reads to high after ECM replacement.
Well, if it worked correctly before then it would be a V8 one. If it was the same one that worked when the V6 was in there then you would have a problem.
I don't even know if there ever was a 145 mph V6 cluster. As long as your oil pressure gauge goes up to 60 lbs and not 80 lbs it should be a V8 cluster
I don't even know if there ever was a 145 mph V6 cluster. As long as your oil pressure gauge goes up to 60 lbs and not 80 lbs it should be a V8 cluster
Last edited by henryd3; Mar 15, 2018 at 03:08 PM.
Thread
Thread Starter
Forum
Replies
Last Post
5.0 Eater
Electronics
4
Mar 9, 2010 08:52 AM