Tach is off.

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Sep 9, 2006 | 06:33 PM

f_bodyman

Thread Starter

Junior Member

Joined: Sep 2006

Posts: 8

Likes: 0

From: DuBois, PA

Car: '91 RS/'69 RS/'01 WS6

Engine: 305 TBI/Undecided/LS1

Transmission: 5-Spd/Undecided/4spdAT

Axle/Gears: 10-Bolts 3.08/3.08/3.73

Tach is off.

I have a 91 RS with a 305 TBI. Recently got the suspicious feeling that my tach was telling me less than the whole truth, so I hooked up a diagnostic computer and was confirmed that it is reading roughly double. Idle at 650 reads nearly 1300 and 1750 reads about 3200. The gauge always works, never cuts out or gets pegged, just is inaccurate. It used to be right on, but no more. Even if it can't be fixed, I'm having trouble finding a replacement. Someone please help.

Last edited by f_bodyman; Sep 9, 2006 at 08:05 PM.

Sep 9, 2006 | 06:39 PM

92droptopws6

Senior Member

iTrader: (10)

Joined: Jun 2004

Posts: 909

Likes: 28

From: Las Vegas

Car: '88 Trans Am

Engine: 5.7L TPI

Transmission: Slushbox

Axle/Gears: 3.27

all factory tach's are off by 400-750 rpm rare they will get that high but i have personally seen it!

Sep 10, 2006 | 01:00 PM

swap350tbi

Junior Member

Joined: Oct 2002

Posts: 31

Likes: 0

From: Mims, Florida

Car: 91 RS Camaro

Engine: 350 TBI

Transmission: 700R4

tach problem

f_bodyman
if you will do a search on tach fix you will find alot of info. on tach repair.
jdmc
swap350tbi
florida
john

Sep 10, 2006 | 09:35 PM

nomind

Member

Joined: Jun 2002

Posts: 181

Likes: 0

From: Bluegrass State

Car: 85 Trans Am

Engine: LB9

Transmission: Finally Fixed (T5)

Axle/Gears: 3.27

Mine did that briefly, you might want to make sure that the dist is properly grounded. Mine was missing that middle ground rod off of the coil. Replaced the coil with a new one, and put that rod in, and it went back to it's semi accurate state.