Hunting at idle, then it cured itself...

[Ian Simmonds]

Started the old girl up today (The S2), she's been stood for about 5 days. Anyway, at idle the revs would drop off and 'catch the stall' bouncing back up, say 600 to 1000 rpm bounce, rhythmically. With a very, very light throttle, she'd sit at 750/800rpm without hunting.

Drove it until fully warm, and whilst less pronounced it still did it.

Started her up later for the journey home, and it was spot on, solid idle, no hunting.

Any ideas? Damp somewhere maybe?

VBR
Ian

[Dan]

I find that if I start mine and immediately give it throttle, it will hunt like that a bit. Always stops once it warms up a little and doesn't happen if I start it and let it idle on its own.

Is this the first time it's happened? If so, I wouldn't worry unless it starts doing it regularly.

[epic]

Faulty ISV valve perhaps

[prj]

Get some contact cleaner, unplug the TPS connector and spray the crap out of it, both the plug and the socket.

I had similar issues - random hunting and bad startup, eventually started getting "Open or Short to B+" errors on the closed throttle switch in VAG-COM as well.
Giving the thing a good spray with the contact cleaner solved all of my problems.

[Ian Simmonds]

Get some contact cleaner, unplug the TPS connector and spray the crap out of it, both the plug and the socket.

I had similar issues - random hunting and bad startup, eventually started getting "Open or Short to B+" errors on the closed throttle switch in VAG-COM as well.
Giving the thing a good spray with the contact cleaner solved all of my problems.

Top man...

Did exactly that, and bingo...

All appears back to normal.

Thank you Sir.

[prj]

Well, let's hope it lasts

[s2driveruk]

hmm, off to get the can of IPA now so see if mine stops too

[Ian Simmonds]

hmm, off to get the can of IPA now so see if mine stops too

Also, check to see of the throttle cable is too tight and stopping the switch from closing.
(or the spring all gunged up).

[s2driveruk]

roger that