tach doesnt work...
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Joined: Oct 2008
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tach doesnt work...
tachometer doesnt work it moves when first starting up but then stays all the way to the right past 7000 rpm... also gas gauge doesnt work, ran out of gas at a quarter of the tank the other day. what can i do thanks
Supreme Member
Joined: Jan 2006
Posts: 3,341
Likes: 10
From: Mooresville NC
Car: LOWERED ♦ CRIMSON METALFLAKE
Engine: ► 400 KUBES ◄
Transmission: 765R4
Axle/Gears: EATON POSI 4.56
Engaging Discussion
Here’s how to test the fuel gage.
Remove the sender wire going to the gage.
Tape the removed sender wire so it can’t short.
Connect a 47Ω resistor to the gage where you removed the sender wire.
Connect the other end of the resistor to ground.
Turn the key to RUN.
If the gage is good it will read about ½ way.
So, if the gage is good, you know the problem is the sender or the wiring going to it.
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Happy Racing!
Remove the sender wire going to the gage.
Tape the removed sender wire so it can’t short.
Connect a 47Ω resistor to the gage where you removed the sender wire.
Connect the other end of the resistor to ground.
Turn the key to RUN.
If the gage is good it will read about ½ way.
So, if the gage is good, you know the problem is the sender or the wiring going to it.
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Happy Racing!
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“After The Fourth Barrel Roll I Lost Control Of The Car”
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“After The Fourth Barrel Roll I Lost Control Of The Car”
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Junior Member
Joined: Apr 2010
Posts: 7
Likes: 0
From: Saint Louis, MO
Car: 1992 Z28 Z03
Engine: 350 TPI
Transmission: AT
Axle/Gears: 3:73
Re: tach doesnt work...
I have similar issue - Tach "kinda" works, as in fluctuates, but at cruising it goes straight to 7000+ rpm's and stays there. Gas gauge works though. I'm trouble-shooting it now, will let you know of any findings. 1988 IROC TPI
Member
iTrader: (2)
Joined: Mar 2009
Posts: 297
Likes: 1
From: Wisconsin
Car: 1984 Firebird (89 Formula Clone)
Engine: 357
Transmission: m29 T56
Axle/Gears: 3.27 9 bolt Borg Warner.
Re: tach doesnt work...
I also have this same issue, my tach is stuck at 7k, and the only gauge working is my battery, and possibly gas i have no clue yet
Supreme Member
Joined: Jan 2006
Posts: 3,341
Likes: 10
From: Mooresville NC
Car: LOWERED ♦ CRIMSON METALFLAKE
Engine: ► 400 KUBES ◄
Transmission: 765R4
Axle/Gears: EATON POSI 4.56
RPM Mayhem
There is circuitry in the dash near the tach.
It’s contained on a small plug-in PCB or integrated in the main board.
On the PCB you’ll see a resistor chip.
Desolder pins 4 & 10.
Use a 500K potentiometer.
Solder it across traces 4 & 10.
Move the potentiometer to half way.
Start the engine and compare the tach reading with a test equipment quality tach.
Dial it in, unsolder the potentiometer, measure it and install a matching resistor.
◙◙◙◙◙◙◙◙◙◙◙◙◙◙◙
Happy Racing!
◙◙◙◙◙◙◙◙◙◙◙◙◙◙◙
I’ve NEVER Hit The Wall - (The Safer Barrier Prevented It)
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It’s contained on a small plug-in PCB or integrated in the main board.
On the PCB you’ll see a resistor chip.
Desolder pins 4 & 10.
Use a 500K potentiometer.
Solder it across traces 4 & 10.
Move the potentiometer to half way.
Start the engine and compare the tach reading with a test equipment quality tach.
Dial it in, unsolder the potentiometer, measure it and install a matching resistor.
◙◙◙◙◙◙◙◙◙◙◙◙◙◙◙
Happy Racing!
◙◙◙◙◙◙◙◙◙◙◙◙◙◙◙
I’ve NEVER Hit The Wall - (The Safer Barrier Prevented It)
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Junior Member
Joined: Apr 2014
Posts: 18
Likes: 0
Car: 1989 Camaro RS
Engine: 305 TPI
Transmission: 700R4
Re: tach doesnt work...
The tach problem is caused by a Resistor going bad. There is a really helpful thread about it here;
https://www.thirdgen.org/forums/elec...meter-fix.html
https://www.thirdgen.org/forums/elec...meter-fix.html
Supreme Member
Joined: Oct 2004
Posts: 4,526
Likes: 238
From: Henrietta NY
Car: 1984 Trans Am L69
Engine: Sniper EFI Powered 355
Transmission: WC T5 w/ Steel Support Plate
Axle/Gears: 3.42 10 Bolt Posi
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