Tachometer about 1/2 to 3/4 actual rpm
Thread Starter
Pro
Joined: Dec 2023
Posts: 652
Likes: 195
From: Katy,TX
Tachometer about 1/2 to 3/4 actual rpm
Asking for some tach trouble shooting on my 64. Since I got the car the tach works no bouncing but is about 1/2 to 3/4 what the electronics on the EFI have shown- Two different EFI systems. They sound correct listening to the motor, pretty sure it would not have a smooth idle at 350-400 rpm.
Cable spins an old race Moroso tach but off on it also but not sure it was geared correctly for the stock distributor-off an old dirt track spring car.
Cable spins an old race Moroso tach but off on it also but not sure it was geared correctly for the stock distributor-off an old dirt track spring car.
Race Director
Joined: May 2006
Posts: 18,653
Likes: 2,557
Asking for some tach trouble shooting on my 64. Since I got the car the tach works no bouncing but is about 1/2 to 3/4 what the electronics on the EFI have shown- Two different EFI systems. They sound correct listening to the motor, pretty sure it would not have a smooth idle at 350-400 rpm.
Cable spins an old race Moroso tach but off on it also but not sure it was geared correctly for the stock distributor-off an old dirt track spring car.
Cable spins an old race Moroso tach but off on it also but not sure it was geared correctly for the stock distributor-off an old dirt track spring car.
Is the distributor a original Delco ?
You mention a Moroso tach, what about the factory tach?
Last edited by MelWff; Yesterday at 12:36 PM.
Burning Brakes
Joined: Sep 2020
Posts: 787
Likes: 791
From: Chapin SC 29036
If you are running a stock tack it might just need calibration.
I had an issue with the tach in my 69 for years but didn't realize the problem was the tach. When I had my dash apart, I took the tach to have it checked. They said it was off by 20%. They calibrated it and I put it all back together and when I started it fast-idle showed 700rpm instead of the actual 1400rpm. Took the tack back out and went back to the place that calibrated it. They apologized for calibrating it 1:1 instead of at 1:2. They recalibrated it (took about 5 minutes) and I brought it home and tested it before I installed it again. Worked correctly and it is back in the dash.
I had an issue with the tach in my 69 for years but didn't realize the problem was the tach. When I had my dash apart, I took the tach to have it checked. They said it was off by 20%. They calibrated it and I put it all back together and when I started it fast-idle showed 700rpm instead of the actual 1400rpm. Took the tack back out and went back to the place that calibrated it. They apologized for calibrating it 1:1 instead of at 1:2. They recalibrated it (took about 5 minutes) and I brought it home and tested it before I installed it again. Worked correctly and it is back in the dash.
