My rev counter's gone mad. I'm now tickng over at 1500rpm and driving at 1000rpm

[auf_wiedersehen_pet]

Spotted it today.

The tickover is now at an indicated 1500rpm. When I pull off it drops to 1000rpm and will then jump up and down between 1000rpm to 2000rpm.

The true engine speed has not changed and seems to be running perfectly.

Anybody had anything similar?

[lambert]

check all the conections on the back of the alternator they can come loose or corrode nd give mad rev readings.

[carracarra13]

had a simmiuler problem with ours but it droped the revs right down is was  the smallest of blows on our manifold all sorted now perfect

[auf_wiedersehen_pet]

check all the conections on the back of the alternator they can come loose or corrode nd give mad rev readings.

Checked all of the connections - no joy.

Good dose of WD40 - hey presto! Sorted.

[Range Rover Blues]

Possibly a wire that's corroded in the terminal then, are any of them crimped?

[auf_wiedersehen_pet]

Possibly a wire that's corroded in the terminal then, are any of them crimped?

By "crimped" do you mean the aftermarket plastic ones. All of mine are standard LR.

[Range Rover Blues]

Yes that's what I meant.  It might still be worth checking that the wire is secure n the terminal but usually I find they are more reliable than the aftermarket connectors.

[stageonesimmo]

This is what I had with mine - an original connector on the white/grey wire at the 'W' terminal had gone - the wire core had snapped just behind the crimp that holds the insulation on the wire and the insulation had hardened so it looked fine with no movement - it wasnt untill I applied pressure along the wire (to lengthen/shorten it) that I was able to match the movement to the tacho's odd behaviour (needs 2 folk to do).  I soldered on a new connector with cover and all has been well since..........

[auf_wiedersehen_pet]

This is what I had with mine - an original connector on the white/grey wire at the 'W' terminal had gone - the wire core had snapped just behind the crimp that holds the insulation on the wire and the insulation had hardened so it looked fine with no movement - it wasnt untill I applied pressure along the wire (to lengthen/shorten it) that I was able to match the movement to the tacho's odd behaviour (needs 2 folk to do).  I soldered on a new connector with cover and all has been well since..........

Coincidentaly, the litle free booklet with this months LRO; Land Rover Troubleshooter says...

Tachometer Fluctuations (Tdi)
The rev counter uses a signal supplied from the alternator W-terminal. Check connections for corrosion and check the eyelet on the connected suppressor is not shorting to earth.