my friend just got a tach and hook up everything correctly, but the tach doesnt show the same rpm as the tach in the cluster. The tach is 500 rpms off. the ground is correct, has power, shift light comes on, and green wire has been connected to tach diagnostic connection. Can anyone help my friend with this problem, the car is 94 civic ex, and the tach is an autometer Monster carbon fiber tach. thanks in advance for the help.

 

The autometer tach is more accurate than the OEM one. The OEM tach is known to be very inaccurate. Trust the autometer tach more than the OEM tach.

 

yea my autometer is like 500rpm off of the OEM tach.......but when I data log in the s300 the autometer is dead on.....go with the autometer number

 

yeah, autometer is better... my oem tach is not THAT off, but maybe around 200 rpm off.