1979 Olds, original tach was reading 500 rpms high at times. Does go to zero when key is turned on. Then when engine starts, rpms still go about 500 too high and
then becomes even more inaccurate at times. The needle does NOT sweep and swing.
Someone mentioned a ground issue but what ground is there to the tach?
Also I did try to solder a wire between the 8 and center contact to do away with the red plastic switch. See pic
I replaced the original tach with a new tach which still has the red plastic switch, and it is behaving the same way as the original.
Where would there be a ground issue????????
then becomes even more inaccurate at times. The needle does NOT sweep and swing.
Someone mentioned a ground issue but what ground is there to the tach?
Also I did try to solder a wire between the 8 and center contact to do away with the red plastic switch. See pic
I replaced the original tach with a new tach which still has the red plastic switch, and it is behaving the same way as the original.
Where would there be a ground issue????????