DISCO 2 throttle with a mind of its own

My much loved 2001 TD5 seems to think its ok to keep changing its tick over... Normally when warm (temp. gauge in the middle) she'll sit around 750 - 800 RPM but today for no reason while she was sitting idling it "bounced" up to about 1100rpm. She wasn't cold and I wasn't anywhere near the pedals.

Took her out for a run and on the way home she did it again while I was waiting at lights. AND again when I was driving slowly round a carpark. All of a sudden, for no reason.....
Can anyone shed any light??

Thanks

check for trouble codes and gat a data logger on your throttle pedal. Also check your cam timing, it don't have to be out much to cause an erratic idle.

Thanks Owl,
will go for the data logger now.......

oh, its not leaking oil out of your turbo into your inlet - causing it to believe more diesels going in....

Oh, that might account for the little puddles on the drive. Another good point to check. Guess I'm gonna be up to my ears in Disco parts this weekend.
Thanks guys..

As others have said, some means of seeing the output from the potentiometers attached to the accelerator pedal would be useful. A Nanocom or similar will allow you to see this. I wonder whether there might be a fault with the accelerator itself or in the wiring loom. My TD5 defender developed what was eventually diagnosed as a wiring loom fault where it would only run on tickover most of the time and would very occasionally respond to the accelerator pedal.

Also don't forget the 'oil in loom' problem which can lead to erratic running.

Hi all, Many thanks for the pointers, Just got back in from the freezing cold having stripped out the ECU to find sufficient oil in the red plug socket to cause me a concern, cleaned that all the way through and ran a test, seems ok so far so I'll keep you updated. Once again the help from you guys is immense
Thanks all.

Could be you've got to the bottom of the problem. However, the key thing is the injector loom itself. Once it's started letting oil leak along the wires it is time for a new one. Pull the multiplug off where it goes into the cylinder head (driver's side, at the front) and see how much oil there is in there. As a temporary fix I've found you can clean it up with electrical cleaner and put it back together, but it really needs a new one.

Thanks for that, I'll tackle that tomorrow.

The only hassles with swapping out the injector loom are the two rear rocker cover bolts (access is a bit limited close to the bulkhead and the rear acoustic cover) AND making sure the rocker cover gasket is sitting correctly everywhere...especially at the rear!

Thanks for the pointers, ordering up the new harness, I'll tackle it when its arrived,