Tachometer running backwards

BKM97423

MEMBER
1983 CHEVROLET TAHOE
2.8L
6 CYL
4WD
MANUAL
86,000 MILES

When I start the engine the tachometer pegs out clear around 360° and stays there. My speedometer is bouncy also. My fuel gauge don't work and says F all the time. This rig sat for ten years only being moved from the guys back yard to the front of his house occasionally. It is idling really high but I don't know how many RPM's because tachometer is pegged.

3 Replies

MOTOR MASTER

MECHANIC
279 POSTS

Hello my name is Dave.

It sounds to me like you have a ground issue somewhere in your instrument panel or in the wiring going to it. Most gauges work on a variable ground and if you ground the signal to them they max out. I have attached our tutorial on testing wiring. https://www.2carpros.com/articles/how-to-check-wiring

I would also like to provide you with the wiring diagram however the vehicle you listed is a 1983 Tahoe and they didn't make a Tahoe in 1983 therefore I can't feel confident I would be giving you the right diagram. If you could update the year/model we can provide you with the diagram and further guidance in tracking down the issue. Thank you for using 2CarPros and hope to hear from you soon with an update.

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Thursday, April 4th, 2019 AT 4:33 AM

BKM97423

MEMBER
48 POSTS

My vehicle is a 1983. I'm thinking the wiring diagram is for a basic 1983 Chevrolet S10 Blazer 4x4/2.8L 6cyl Chevrolet S10 Blazer Tahoe Edition 2.8 liter 6 cyl 4x4 The owners Manual just says S10 on the front. I have found applications that say 1983 Chev S10 Blazer Tahoe Edition. The glove box says Tahoe on it. Can you recommend an effective surface rust treatment/remover or stabilizer to use so the surface rust doesn't continue getting worse. Thank you for you time, You are much appreciated 2carpros. Com

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