reklim

I put a new sensor on it today but it didn't fix the problem. Then checked power to the tach it was 12.9 v, the leads going to and from the sensor each read about 4.1 . After that i figured i had nothing to lose so i started changing the dip switches and with a certain combination the tach started working correctly. I put the tach back in place restarted the truck to make sure it still was working and it was ,but an hour later when i cranked it, it started reading low again exactly as it had before .Thanks for the advice

Mine does have dip switches but i don't have an old tach to match. What could cause it to get out of calibration? Could the problem be a bad engine speed sensor( if that's what you call it ) ?

I recently bought a 1998 ch613 tandem dump, and now busy trying to fix everything on it. Would anyone have an idea why the rpg gauge reads low. The engine runs fine and has power but the gauge only reads between 300 and 700 rpms ?