I had a working tach until I swapped engines last year. I don't know if it's the crank sensor or the electronic module deal on the fender well. I know that the gauge itself worked fine until the engine swap. Looks to be pretty hard getting that crank sensor removed.

Thanks, Mark

Yes, dealing with the sensor wire can be difficult. I pulled from from the bone yard, the radiator was missing, as were most of the belts, wasn't too bad. A new, or adjusted amp is easier, yet may or may not be the problem. They do fail routinely tho.

__________________
83 SD

84 CD

There must be a way to test the rpm sensor with a multimeter. My 84 euro 300TD was originally equipped with the rpm sensor pickup even though it was not equipped with a tach. The rpm sensor feeds into pins #2 and #6 at the connector on the fender wall (pin #3 goes to the tach). I assumed that this set up was so the factory (and service techs) could read the engine rpms.

I will play with it this afternoon after work and see what I can find.