Rec Counter under reading
 

Hi,

1983 911 SC 3.00, the rev counter is reading way too low, probably half what it should, it was working fine a few months ago, any ideas?

Many thanks Stephen

Just bumping this, any ideas anyone?

Holy smokes - three years almost between posts - you got some patience.

Not being a tachometer wizard, I would start with electrical connections. The CDI box feeds the tach.

Permatune has a nice web page detailing the 6 pin connections. Make sure the tach wire is well connected. Even unplugging and re-plugging the harness can do wonders for skanky connections.

Perma Tune High Performance Ignition Systems

Get into the luggage compartment and push out the clock - into the passenger cabin. Then push out the speedo and tach. I don't remember if you need to start them from the luggage compartment and then finish the pull out in the passenger compartment. I do remember if you get the clock out it facilitates removal of the other gauges.

Check all connections one at a time on the tach. Look for corrosion, etc. It has to be something simple