fix didn't work
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Joined: Mar 2010
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From: IOWA
Car: 89 IROCZ
Engine: Forged 347 LS1
Transmission: Built 4L60E with 4k stall
Axle/Gears: 4th gen w/ 3.42 gears
fix didn't work
Hello all... I have an 89 iroc with a 350 tpi. The tach was reading too high all the time, I tried the tach fix by replacing the capacitor and it is still the same. Any body have any idea as to what could still be wrong with it.
Thanks,
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
Inna Terrible Fix
There is circuitry in the dash near the tach.
It’s contained on a small plug-in PCB or integrated in the main board.
Also 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!
◙◙◙◙◙◙◙◙◙◙◙◙◙◙◙
How bout those too scared to drive without headlights in the daytime
and the ones that need headlights for a little rain
.
It’s contained on a small plug-in PCB or integrated in the main board.
Also 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!
◙◙◙◙◙◙◙◙◙◙◙◙◙◙◙
How bout those too scared to drive without headlights in the daytime
and the ones that need headlights for a little rain.
Joined: May 2009
Posts: 4,915
Likes: 40
From: Far West
Car: 1986 Camaro Z28 IROC-Z
Engine: 350 Tuned Port Injection, for now.
Transmission: 700R4
Axle/Gears: Posi - 3.23
Re: Inna Terrible Fix
There is circuitry in the dash near the tach.
It’s contained on a small plug-in PCB or integrated in the main board.
Also 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!
◙◙◙◙◙◙◙◙◙◙◙◙◙◙◙
Happy Racing!
◙◙◙◙◙◙◙◙◙◙◙◙◙◙◙
How bout those too scared to drive without headlights in the daytimeand the ones that need headlights for a little rain
and the ones that need headlights for a little rain.
Joined: May 2009
Posts: 4,915
Likes: 40
From: Far West
Car: 1986 Camaro Z28 IROC-Z
Engine: 350 Tuned Port Injection, for now.
Transmission: 700R4
Axle/Gears: Posi - 3.23
Re: fix didn't work
Never mind. I didnt realize that they are huge.
Thread Starter
Member
iTrader: (2)
Joined: Mar 2010
Posts: 166
Likes: 0
From: IOWA
Car: 89 IROCZ
Engine: Forged 347 LS1
Transmission: Built 4L60E with 4k stall
Axle/Gears: 4th gen w/ 3.42 gears
Re: fix didn't work
thanks for the info but i only know enought with electrocis to dangerous... can you put this in dummy terms for me?
Joined: May 2009
Posts: 4,915
Likes: 40
From: Far West
Car: 1986 Camaro Z28 IROC-Z
Engine: 350 Tuned Port Injection, for now.
Transmission: 700R4
Axle/Gears: Posi - 3.23
Re: fix didn't work
take a look at this picture. https://www.thirdgen.org/forums/atta...-dscn2812b.jpg
This is the board that needs to be modified (pins 4 & 10).
To better understand the process of fixing the issue at hand, your gonna have to read the info. The info is very valuable for repairing the tach.
https://www.thirdgen.org/forums/elec...meter-fix.html
This is the board that needs to be modified (pins 4 & 10).
To better understand the process of fixing the issue at hand, your gonna have to read the info. The info is very valuable for repairing the tach.
https://www.thirdgen.org/forums/elec...meter-fix.html
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