Thread: 300 tdi idle problem

does it hunt badly?

you dont have your aircon on do you

and what does it hunt between...

The idle is probably set a bit too low.

I recall factory idle being 720+/-20rpm, but in reality it is more like 750-760rpm.

Try adjusting the idle screw a tad to the point at which the hunting goes away.
This is the screw that the accelerator lever at the pump rests on when at idle.
You may need to drive it, test, and adjust it a couple of times to get it right.

It will only be a small idle adjustment, but you might as well adjust the throttle cable while your at it.

Tighten the throttle cable near the pump (black plastic thing on the cable) until it just moves the accelerator lever at the pump, then back it off a touch.
After driving if the engine doesn't go back to idle fully, just back the throttle cable off a tad more.

You may now also need to adjust the kickdown cable, but unless you are unhappy with it, I wouldn't bother.

Cheers I shall have a fiddle later an see if can make it better than it is.

Blknight answered this on another thread ages ago- and I can't find it. But correct me if I'm wrong, as I'm only going on a vague memory of it, but I think he may have said it could have something to do with the governor in the injector pump(all other things being checked OK). A few Tdi autos do it I think, mine does it but not all the time. Mine seemed to be more noticeable when I replaced the injectors(could've been coincidence, don't know) A search will bring up a few possibilities and will probably lead you in the right direction, especially in things to check. Raising idle speed can mask it, but then your idle will be too high when in Park or Neutral.