I have just replaced the temp sender on my K-Series engine after damaging the old one through being too heavy handed.

Since replacing it, I have noticed significantly increase temperatures and interference, i.e. the temp increases 10 degrees when I turn the lights on.

I have been back through the wiring and cant find any shorts or faults. I am about the by another sensor, but thought I would tap into the collective knowledge first for any similar experiences.

Cheers,

Sounds like wiring related, probably a bad earth somewhere.

On most K series the temperature sensor works through the MEMS ECU, Rover ECUs are prone to bad earth connections.

But we really would need more info is the temperature gauge wired as per standard Rover ? Has the car 1 or 2 coolant temperature sensor IE 1 brown & 1 blue ? if so which did you replace? Later MEMS system used only a single blue sensor the gauge reading being entirely driven by what the ECU wants to show you IE it is an over heat gauge not a temperature gauge.

So (1) Check the battery to chassis earth, (2) Check the engine to chassis/battery earth.
(3) Clean the connection of the ECU earth.
(4) Clean and check the ECU main connector
(5) Check you have fitted the correct colour code sensor.



[Edited on 24/4/14 by britishtrident]

My wife does tell me I only ever give half the story.

The sender is independent of the ECU, it is wired directly to a green gauges temperature gauge.

I had suspected an earth fault also, but have struggled to identify. Also it has only occurred on changing the sender.