71 XJ6 tachometer not working
 

Hi everyone:
the tachometer is inoperative, and has been since we purchased the car (35k original miles).

The needle is pegged all the way to the right (redline), I do not know if this means anything. All the other gauges are working.

Any assistance would be appreciated, and thanks in advance!
Paul

Bump?
Anyone?

My guess is a mechanical failure somewhere in the innards of the thing....that is, something simply broke....and that an instrument repair shop can fix things up.

Cheers
DD

Or, a lessor guess.


Most rely on the make and break of the distributor to create a pulse, in turn converted to mechanical movement. Classic electro mechanical technology. As it is the ground leg that is make and break, I would suspect it is grounded all the time, not off and on ground...


Find the ground lead to the - post on the tach. Disconnect it. Fire the engine. If it drops to 0, I got it. If not, Doug's theorem is most likely.


Carl

Thanks! I will check all wiring (at the tach too). Everything at the distributor and coil is connected, but I will try disconnecting and turn the car on to see what does or does not happen.

Will keep all posted.