Finishing up a 97 t/a 6 speed with 24x conversion (0411 pcm). I have been playing with the tach output high and low setting in the tune, and setting both to 3 the tach reads really high, and when I set to 4,5,or 6 the tach reads closer but then it read off by different amounts as I rev it up.
1996 Camaro Z/28 M6 LT1 touched by the LS1
2011 Sierra 4X4 6.2L Header, CAI, LS7 Cam
Come on, no one has had this issue?
1996 Camaro Z/28 M6 LT1 touched by the LS1
2011 Sierra 4X4 6.2L Header, CAI, LS7 Cam
What kind of Tach are you running? V8 tach reads 4 pulses per revolution, so 24/8=3. 6 cylinder tach reads 3 pulses per revolution, so 24/6=4. 4 cylinder tach reads 2 pulses per revolution, so 24/12=2. These are the "N" numbers for above that are plugged into the HP Tuners Tach Output fields.
Jake Hatfield
Central KY
stock 97 T/A tach and cluster. I have tried so many settings hoping to get something to work. installed a Dakota digital tach adapter box, still not working properly. I can get it read very close at idle, but by 4k rpm the gauge will be 700-800 rpm slow
1996 Camaro Z/28 M6 LT1 touched by the LS1
2011 Sierra 4X4 6.2L Header, CAI, LS7 Cam
Is the stock tach in the car a 4 cylinder 6 or 8 cylinder? If it was a V8 car, it would either be a 4 or 8 cylinder tach...if it's a V6 cluster, then it's probably a 6 cylinder tach.
In my experience, some GM V8 cars are 4 cylinder tachs, and the correct setting in the PCM would be 6 and 6. Some other GM V8 cars are 8 cylinder tachs, and the correct settings for them would be 3 and 3.
Have you tried another cluster? Have you verified there are no ground issues anywhere in the vehicle? I would remove the aftermarket module (and do a really good job repairing any wiring you modified...replace it if necessary), the tach signal between the GM PCM and GM Cluster in that vehicle should be very simple...if it's not reading right, there's another issue. A tach signal through butt connectors, or wire taps, will have issues and read incorrectly. Any signal wire carrying a frequency should be treated with a little more care.
2010 Camaro SS M6. Stock Bottom End, Heads/Cam/Intake/Headers/Exhaust.
2005 Silverado RCSB. Forged 370 LQ9/Borg-Forced Inductions T6 S484/Jake's Stage 4 4L80E with D3 Brake/4WD.
2023 Durango Hellcat
there is a resistor tach mod i think a while back for lt1 swap guys. google it should come up.
I had the same issue with a customer's 95TA. set as 3 and 3 and "write entire".
I feel like it's not the same for the 96-97s. That does indeed work on a 95 though.Originally Posted by strokedTA
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