Tachometer on 300 TDI 1995 Disco

[Tig]

Mine keeps flicking up and down (even at a constant speed) any ideas anyone?
I dont know where the tacho takes it's feed from so I'm a bit stuck.

[gords]

I dont know where the tacho takes it's feed from so I'm a bit stuck.

It connects to the alternator - check all the wires / connectors are tight.

[Budgie]

This is a common fault with the 300Tdi and as Gords said the problem is normally with the connection at the rear of the alternator.

It's either a white wire or black/white wire onto a spade connector, these connectors are not very good and you can either replace it with a new one (which for me has cured the problem for the last 5 years) or clear up the connection and try to make it tight again by crimping the spade connector a little.  

[Tig]

Spot on! Thanks lads  :D

[Budgie]

Glad we could help Tig.  :D

[kwik.kwak]

my  rev counter has packed up altogether, will it be the same problem ????

[Budgie]

It's worth checking it.
Find the wire described above, see if it is loose on the connection onto the back of the alternator and pull it on & off a few time, then replace it and start the engine. If there are signs of life from the tacho then try replacing the connector on the wire.

The cost of one female spade connector is much better than a new tacho!!