Idling issues

[wackyracer]

Have read a few threads on idling issues but can't find a answer that seems to match my issue. The last post by kineticz was close though!
What started off as a occasional problem is now happening everytime.
When the car is started from cold ( as in left overnight cold) it will start fine, engine revs up to 1200 etc, but then the idle hunts and goes up and down and may even stall. If you try to drive off it will hesitate, jerk and possible stall unless you really give it some welly (4000 plus). However once the revs drop back to 800 it will drive fine.
the plugs are fine, the coolant sensor is fine and a new type, the coil packs are either new or fine and it shows no codes. Just gone through mot fine and emissions were very good.
This problem only happens when cold as above.
what should i be looking for? Could it be a dirty throttle body? Kind of ruled out the maf as runs fine allt he time except that first 30 to 45 seconds.

The car is a 2000 x reg 1.8 20vt cupra with a AUQ engine ( yes it really does have this one!)

thanks guys.

Oh by the way is anyone out there is dispairing witht he price of full again, i have now had my lpg conversion for a years and its been great. No problems, 54p er litre for fuel, and no loss of performance! Any questions any one may have if they are thinking of it themself, i would be happy to share my experiences!

 

[Keithslippery]

Have you plugged vag com in does it give off any fault codes...

 

[wisejason]

could be the throttle body mate... my car did this in the cold weather last year before I cleaned the TB. not quite as bad cause it never stalled, but it used to almost die/drop off to a splutter. Found a good tempory solution was to start the car and let it tick over for a few seconds and then turn if off and back on.

A gasket for the TB is only a few pence and a can of carb cleaner is about £5 quid, takes around 20-30 minutes to take the TB off and clean. Worth a try in my opinion.

 

[LEE69]

Needs re-setting then, see the sticky in this section

 

[wisejason]

Needs re-setting then, see the sticky in this section

very true forgot that I did it with VAG-COM afterwards...

 

[wackyracer]

Have you plugged vag com in does it give off any fault codes...

no i havent. i dont have a copy of it. But i do have a plug in vw code reader that has been excellent in pulling basic codes off in the past. Tried that but noting showing. I do tend to agree that for very little effort the throttle body clean seems very worth while!

 

[cupra-paul]

i had a problem with an auq that sounds just like that, i replaced loads of sensor (a good £600 worth) and they did nothing to improve it, it went to an auto electrians for 2 weeks and he couldnt fix it, it even went to a seat dealer, the only thing they thought it could be was the variable valve timing solinode on the engine was sticking (£600 new part), instead they recomended use engine flush and then and do an oil change, did this expecting it to be no better but it has not done it since, honestly mate its likely suspect and the cheapest to try. if you want any more info let me know. let me know how you get on

 

[jonisginger]

I have a similar problem! 51 plate S, except if you try and pull away from cold the engine power can drop and it won't rev for a few seconds, then its fine,

if you boot it so its hot then stop and let it idle the revs dip up and down (only by 50 or so) and it stops if you put the heater onto max temp and let it blow out at 2 or 3.

it never used to do this? any ideas?

 

[wackyracer]

quick up date...
cleaned the TB today.... omg! It was thick with grease, carbon and whatever else... i mean you could write your name in it! little bit of oil too, and also alittle on the rubber hose. Anyway gave it a good clean and also the hose etc. Fitted it back on etc. Don't have VAg.com so went down the 'let it run for a while to reset' avenue. EEKK! Car ran like a bag of spanners despite revving it, leaving it etc etc for over 15 mins. Thought 'oh dear...'.
Went back and checked all the connectors etc and all fine. Pulled the codes and got 17972, which made sense. I tried disconnecting the battery for 5 mins and then reconnecting and bingo! Runs sweet as a nut! If anyone else is having to do this without vag and gets this problem then do try the battery thing, may be a red herring but worth a try. Also wondered if a bit of moisture had got into plug etc?
Anyway havent tried it from stone cold yet but will try in the morning and report back.
thanks for all the bits of advice guy, much appreciated.

p.s strange thing was it ran better on lpg than petrol when it wasn't set correctly? Maybe to do with the cleaner burn etc?

 

[jonisginger]

Wacky did you take it all off? The TB?

 

[soulman]

I've had this on and off for the last few years on my 2002 1.6 Leon.

Had the coil packs replaced, EGR valve and throttle body cleaned numerious times. It's started again this weekend, plus the high pollution light came on. So I took it down to my local Skoda dealer in Bolton and the following error showed "CATALITIC SYSTEM BANK1 INEFFICIANT BELOW THRESHOLD" which means the cat needs replacing.

The cat was replaced in 2008, so hopefully I can get it changed under warranty.

 

[wackyracer]

yes i took the whole TB off and gave it a though clean. Car seemed alot smoother today both idle and drive wise. In fact i know it may be all in the mind but she seemed more responsive throughout the range.
When i started her tonight she did stutter just a tiny bit but will have to wait to see if i have fully cured the problem.
Just a note to others.... When i had the cambelt replaced a short while ago it seemed to help the idle alot. Garage said it could have been that they do stretch a little bit with age and as mine was about 85k he could have been right. worth thinking about if yours is alittle old, even though if it's that old you should change it anyway!

 

[jonisginger]

Do you have to clean where the throttle body came off or just the TB itself? How long did it take you and what stuff did you use? Think mine could probably do with cleaning.

 

[LEE69]

Spraying into the inlet with car cleaner will not hurt it

 

[jonisginger]

Cool. Think I'll give it a go next week!

 

[wackyracer]

Decided to clean it all while it was all off. The bit where the rubber pipe goes on was caked with limescale and also just inside the pipe so cleaned all i could get to. I picked up what i thought was carb cleaner from my shed but turned out to be engine cleaner, but it did the job. Sprayed it in while holding TB upside down to allow to drain. Also used a soft cloth with some on to clean the sensor just inside the intake on the engine... goes easy looks like a resistor there! Whole job took about 30mins, but if wasnt so bad could have got that down to 15 to 20. Just don't rush it.
I remember when i used to mave my mazda mx6 and people used to bore out the TB lip to gain extra power. I have noticed a much better response from mine now and thinking that a mm of gunk would have cut air flow a little!

 

[jonisginger]

By jonisginger

 

[wisejason]

quality image - LMAO

 

[jonisginger]

also sawm 3050m this morning, AND sorted my finances out AND going (hopefully) to see my hot mate at Uni tonight

today is TRUELY success day

 

[wackyracer]

I loved that pic too! Class act.