Throttle hunting at idle..

[TheClaw]

last night my car starting doing a weird thing. After it warmed up, at idle the throttle will go from like 1,100rpms to 1,400, then drop back down to 1,100. This whole process takes about 3 seconds, and then just repeats and keeps doing it over and over.

While I;m driving, it doesn't do anything weird, just while idling.

Any ideas where I should look first?

Thanks for the help.

 

[jackalopeTsi]

This has happened to me a lot. i had some pretty bad boost leaks. and it will happen if you vent your blow-off valve(ive done it before). get a leak tester and check for leaks.

 

[TheClaw]

This has happened to me a lot. i had some pretty bad boost leaks. and it will happen if you vent your blow-off valve(ive done it before). get a leak tester and check for leaks.

Is there a write-up somewhere on how to check for boost leaks? I have no idea where to start..

thanks

 

[ddavisaf]

http://www.vfaq.com/mods/ICtester.html
Also pick up a Hayne's or Chilton's or something and check your Idle Speed Controller (ISC)

 

[v8s_are_slow]

could also be a bad isc motor (as stated).

http://dmtalon.v8eaters.com/ISC.html
http://www.dsm.org/how-tos/tttt/tttt3.html

 

[Tsi_User]

Or you might have the 91 idle problem that quite a few of us have on the boards, many of us still haven't figured it out. Hell, I even took mine to a shop and they had no clue what it was

Mine fluctuates at warm up and for about the first 5 minutes of idle and then it "fixes itself". I've replaced my ECU, plugs, wires, ISC, checked for boost leaks and checked the MAS.

If you do happen to fix your problem PM me

 

[92awddsm]

As stated, check the isc. Thats is normally the cause for the idle surge.

And also make sure the ground strap is still on the trottle body. It is screwed to top and folds over the front of the tb elbow and has one of the mounting bolts going through it. I had similar problems and it was all from the ground strap not being there.

 

[RUSURE]

Will all this information work for the 2g's AWD tsi Talons? It sounds like this is the exact problem I'm having right now. Is the IAC the same as ISC?

 

[RUSURE]

Will all this information work for the 2g's AWD tsi Talons? It sounds like this is the exact problem I'm having right now. Is the IAC the same as ISC?

95'

 

[redboosted97]

ISC is dough bro, dealer only part!..........320bux. You can find a rebuilt one for around 100 bux.

 

[steve]

Will all this information work for the 2g's AWD tsi Talons? Is the IAC the same as ISC?

Yes and Yes. Which name just depends on which manual your reading.

Steve

 

[Tsi_User]

ISC is dough bro, dealer only part!..........320bux. You can find a rebuilt one for around 100 bux.

or there's always the graveyard, I've bought coil packs, ECUs and ISCs off of them without any problem

 

[9!'clipseDOHC]

It is definitly your ISC. You can get a brand new one at www.dsmparts.com for $244 or i got a used one at a junkyard and it fixed my problem. However getting a used one you run the risk of getting another bad one and still having the same problem.

 

[steve]

You can greatly reduce the chance of getting a bad one by checking the coil resistance as you pull it. ISCs with good resistance measurements on one coil, either pins 1-3 or 4-6 are donors for rebuilding or to be rebuilt. A pair of bad ISCs each with one bad coil will make one good ISC.

Steve