Intermittent tach on 328

Could be the sensor on the flywheel - had a similar problem and changed out the sensor which corrected the problem. There is an ohms-based test for testing the sensor (do a search under "crank sensor"). If it's not the sensor then it could well be a connection in the guage, possibly an intermittent ground.

 

The easiest thing to do first is pull the cluster and check. You can pull it by pulling the lights at the 4 corners of the cluster and the screws are behind them. Use silly putting on your screw driver so the screws won't fall after removal. From there it should be easy to verify if it's the connection or something before it.

 

Tachs with 3.2 motors are prone to fail. The thing to do is take it out and send it out for rebuild. There is a place in Palo Alto and another in Albuquerque. Cost is pretty reasonable. Someone here can provide the address if needed.

Dave

 

and posted the results for the benefit of all here.

Die kittens die.

Its the calibration pot, on the board, inside the unit, that gets carboned up, just like a slide type rheostat volume adjustor on an old hi Fi, that gets dirty and crackles like hell when adjusting the volume.

Clean out the calibration pot and it works guaranteed.

Skin.

 

I sent my to Palo Alto Speedometer, ran about $140 or so, plus shipping each way. They turned it around in 3 or 4 days. But call ahead for turn around times, as it can very by time of year.

 

To answer your question about the ease of checking/removing the crank sensor, no, it does not require a removal of the engine/gearbox. All you do is remove the left rear wheel well surround and you'll be able to trace the sensor wires to the sensors mounted on the engine case by the flywheel. You can check the proper functioning of the sensor without removing the sensor - just trace the wire to the connector and perform the ohms test there - should read in the neighborhood of 500-700 ohms if functioning properly.