Tachometer

Hi Guys!

My tachometer is not working. it jumps all over the meter. how do i fix it?

The tachometer in my 1992 sarted dying intermittenly while I would be driving. I tried everything. I took the cluster out, checked continuity of the wires, reseated connectors, tightened screws but nothing helped. I finally bought an instrument cluster from a junkyard and swapped my original speedometer into it to retain the mileage. Don't forget to change out the bulbs if you get one from a junkyard.

Excuse some silly questions first:

1. by tacho, I presume you mean rev counter?

2. is the car petrol or diesel??

If it's a petrol, then the gauge is knackered. The gauge actually works by picking up the pulses in the ignition line (every time the engine sparks, it sends a pulse down the ignition line). Pretty noddy system - not much to go wrong apart from the gauge.

If it's a diesel (or a wierd petrol system), then chances are the "tdc sensor" is knackered. This is a little magnetic sensor which sits on the flywheel and gives a pulse every time the flywheel passes "top dead centre". They are prone to going faulty...