The tachometer on my 81 300 SD turbo diesel only works once in a while - I am not fimiliar with how mercedes senses engine RPM on their Diesels.... Is there a sensor on on the crank or something?
are their any cronic problems i should know about with the tach on this model?

Any thoughts greatly appreciated

thanks!

-Dan

 

There is a pickup behind the pully on the front of the crank. Check the wire to it. Also, the tach transmitter is a gizmo on the driverside inner fender (engine compartment) it's round, about 2" diameter, it plugs into a socket. They go bad once in awhile, but try cleaning the contacts. Also make sure the connection is good on the back of the instrument cluster. On my 85, there is a small wire connected to the positive side of the battery that I left off by accident once. It caused the tach and A/C not to work....good luck!