Just noticed today that the idle on my TT is sticking at 2000rpm when I've backed off the throttle gently. If I rev the engine slightly (to around 3000) and then let go of the throttle sharply, then most times it drops back to a more normal idle (just under 1000rpm).

 

What's the most likely cause? (and fix for it)

Hi,

Don't really know the first thing about these cars - got mine last weekend but do a search on Throttle Position sensor,

Sounds like something is sticking slightly when you move the pedal gently but not when it's released??

 

Just a thought

 

Regards

 

Glenn

Check the ECU for errors.

 

Then clean the TPS and the temp sensors. They are probably the first port of call.

 

Reset the ECU after you clean then (i.e. disconnect the abbtery for 30 mins to an hour) then see how it goes in 50 miles time (ECU has to relearn so it takes a few miles).

Could also be a sticing cable.

Check the throttle cable to see if it is too tight or too loose. may want to grease it up a bit :eek:

unplug and replug the connector on the tps and waggle the wiring underneath it when idling - if its there you will hear the tickover change immediately.

 

Also listen for hissing around the engine bay when idling implying a small air tube has come off or is leaking. I had one just in front of the battery with a cracked T piece. New T piece and idle back to normal

Ok, I've found where the problem is, but I have no idea how to explain it (or fix it). Is anyone online that I can email a couple of pics to for upload, as it'll be easy to explain then.

 

{Have been trying for the last 30 minutes to upload stuff, but my NTL ftp won't work at all (first time I've used the NTL ftp account and it is playing up big style)}:mad:

Ok - here's the image...

 

http://www.j-s-y.supanet.com/thing1.jpg

 

The metal bit that the hand is pointing to doesn't go all the way down to the stop when realeased gently, but does if released quickly or if you press it about 1mm (or less) with your finger. At that point the revs drop to a normal idle.

 

I'm guessing the the brown spring on the left is not strong enough. Can it be adjusted? Do I need a new spring?

 

I have greased the end points of the bar that turns when you press the throttle to see if it would move more freely (Feel free to tell me the correct name for it - I'm as technical as a mushroom).

 

Help please?

I might be wrong here, but cleaning the throtle bodies could help.

 

Remove that big black pipe and clean inside the chamber with carb cleaner and a toothbrush. Don't forget to keep the throttle open while cleaning the butterfly.

 

Vijay

Cool - I'll pick up some carb cleaner tomorrow and give it a try.

 

Thanks for the advice.

It seems to be a bit better now - it wasn't much different after I'd cleaned the throttle bodies, but a day or 2 later it started to improve - I don't know if the last bit of dirt was clearing out or if the grease was working its way in.

 

The last bit of the rev range (2000 down) still drops fairly slowly, but at least it drops :)

 

Thanks for all the help and advice:D

did you re-set the ecu by leaving the battery disconnected for an hour or so? If not, you should :)

 

Vijay

finally got my idle probs nailed down to the IAA unit. Had a chat with Luke and he reckons its a common failure.....maybe worth a pop if all else fails.