Erratic Tachometer
 

Perhaps some one of you has had a similar problem. I have a 1984 Carrera and recently am experiencing intermittent tachometer bouncing. Initially the tach would jump to a higher rpm but now pegs. When I rev the engine it drops below the red line. Perfectly fine yesterday but problem again today. Suspicious that it is a poor ground but I did check fuses to make sure they were all seated well and making contact. When the tach is working properly it is spot on so I don't suspect the tach but could be wrong. Would appreciate your input. Thanks

Al

While it could be a bad ground ... I suggest monitoring the system Voltage to see if normal, high, or eratic, and if any fluctuations match when the tach goes erratic.

Traditionally, an erratic tach is a sign of Voltage regulator problems.

Tach
 

Ah ha, thanks, will do.

You probably shouldn't drive the car too far from home until you figure out the problem...if it's a bad VR the battery may soon fail, leaving you stranded. Ask me how I know... :mad:

Early - s- man is right again!

Thanks
 

Thanks for your input. I've decided to not drive until wringing out the problem. My fun car garage is in another city so will pick up tools tomorrow and have a go at it.

Al