04-23-2006, 11:56:33 PM
i bought an autometer super comp tach for my 74. I hooked it up and it shows too high of an RPM. Is shows 7000 when it should be around 4000. Also the shift light will no turn off. Can this be a wiring problem. I am using HEI. thanks
04-24-2006, 12:05:46 AM
It sounds like you either have it wired for a 4 or 6 cylinder, or have to switch it to 8 cylinder. I don't exactly how the cylinder selection works on those tachs.
04-24-2006, 12:12:57 AM
On the back where the wires come out you will see 2 short wires that are looped back into the tach. I forget the color codes but you cut one for a 4 banger & cut the other for a V6.
Both need to be connected for a V8 engine.
04-24-2006, 11:35:18 PM
i found that the 2 wires were cut. Now the tach reads correctly, but the shift light still stays on all the time. Does anyone know a reason for this?
thanks for all your help
04-24-2006, 11:44:32 PM
What model tach is it? Does it have a black knob on the face?
The way you set those tachs is to turn the ignition key to on(not start the car) & the tach needle should move to where the light is set for. You can turn the knob at this point to set it at your redline.
To test it, set the shift light for 3000rpm & then start the car & rev it to 3100rpm, it should light up.
It's probably set right now for something below your idle speed.
04-25-2006, 12:12:32 AM
it is an autometer super comp. i will try to adjust it again tomorrow
04-29-2006, 12:18:12 AM
i have tried everything to get the shift light working. it still just stays lit no matter what.