Very strange cold start behaviour what do you think ??

[8YA335TDI1STED]

as the cold snap has crept in ive noticed some very strange behaviour on the first cold start of the day

turn key car starts some what lethargically , revs jump too around 1200 rpm then drop way back down yo almost stall , this happens 2 - 3 times with the revs jumping to 1200 rpm and back down again and the engine stumbles and threatens to stall , but within 4-5 seconds it settles to rev at 1100 rpm then drops to normal revs within normal time once the cold start valve stops also noticed a hunting idle = +/- 50 rpm when warm ??

where should i start looking for the problem here folks I recently cleaned the maf and throttle body none of which cured the prob ?? and unfortunately dont have vag com untill santa comes lol

 

[S3BAM]

Lambda sensor can cause running issues

 

[coyle]

coolant temp sensor can cause unsteady starting from cold, or so im told as i have a similar issue

 

[8YA335TDI1STED]

tis very strange has only happened since the temp dropped it was 2deg yesterday and 1 deg today both times i used the car for a 2 mile journey which is over just as the thermo opens then let it sit for a cpl of hours back out for journey home engine cold but no repeat of the problem very strange only seems to happen at first cold start after the car has been sitting all night

 

[S3KO4]

Make sure you have enough red coolant liquid in there it could be a case of part of the water frozen, and the water pump might strugle.

 

[8YA335TDI1STED]

Make sure you have enough red coolant liquid in there it could be a case of part of the water frozen, and the water pump might strugle.

very good advice m8 but dont think thats the problem , I had engine flush and new coolant plus stat fitted last month, along with full engine service inc timing belt ? but ill have the coolant tested to see if its up to spec just incase

 

[s3dave]

Im thinking dying battery mate to be honest..see if it gets worse

 

[8YA335TDI1STED]

Funny you say that dave when i bought the car, it had to get a jump and i had the same symptoms once before when it wasnt so cold afaik last test alternator was producing 14 + volts so charging ok , maybe the battery is tired will get that tested too

 

[coyle]

I can leave mine 5hours when im at uni and its fine,only does it on 10+ hours eg overnight

 

[A3tell]

maybe the throttle body posisitioning needs resetting, was told this when mine started to play up, its pretty easy to do, turn the key on but dont start, if you listen carefully you will hear a faint buzzing sound, leave the key untill the buzzing stops, then start the car, if this doesnt work, then you may have a couple of fault codes logged from when your battery died and needed jumping, they will need to be cleared for it will run right. hope this helps.

 

[richie_jones]

maybe the throttle body posisitioning needs resetting, was told this when mine started to play up, its pretty easy to do, turn the key on but dont start, if you listen carefully you will hear a faint buzzing sound, leave the key untill the buzzing stops, then start the car, if this doesnt work, then you may have a couple of fault codes logged from when your battery died and needed jumping, they will need to be cleared for it will run right. hope this helps.

I might be mistaken but i don`t think reseting codes makes any difference to the way your car runs....

 

[gavin89]

I might be mistaken but i don`t think reseting codes makes any difference to the way your car runs....

correct! mine has the same symptoms as OP, vagcom points to the MAF (too lean), but thats been cleaned and checked. I think temp sender still might be the case...

 

[A3tell]

well, when mine had hunting problems, (revs searching) i took it to my garage they plugged in and found a couple of voltage fault codes from when my battery died, which they cleared, and the car was instantly cured!
just speaking from my experience.

 

[8YA335TDI1STED]

noticed today started the car with drivers door open and could smell un burnt fuel a mile off , gonna wait untill tm and take a vid of this strange behaviour n c what u guys think

 

[pj123]

MAF, spark plugs, fuel pump relay or temp sensor.

Cleaning MAF didn't cure my MAF so prob wise not to rule that out just yet, need to log air flow with VAG COM or unplug before starting up...

 

[8YA335TDI1STED]

****** wheres the best place to buy vcds in the uk ? it seems much cheaper from ross tech direct so whats the catch anyone know ?

 

[coyle]

I would like to know too, i want to get myself a copy

 

[DaveA3]

just get vcds lite (free download from rosstech) and an ebay cable. i got my cable from deal extreme. DealExtreme: $12.96 OBDII V600 USB Car Diagnostic Cable for VW/Audi/Skoda

works well on my laptop and does all the stuff i need it for. if ur just checking and clearing fault codes its fine. Can also do measuring blocks etc

 

[Westy]

If you do a search I had this problem last year and went through changing the temp sensor, cleaning the TB and a few other things. I managed to fix the problem in the end by changing all 4 coil packs as it turned out that 1 or 2 of them were dodgy in the cold.

 

[8YA335TDI1STED]

as for vcds has anyone come across this before are these guys legit ? does anyone know ? they claim full funcionality at a third of the price
VAG Diagnostics Ltd - VCDS Vag-Com 908, 912, & 10.6 Cables - Sales

 

[8YA335TDI1STED]

heres a vid of what happens , very strong smell of unburnt fuel when it behaves like this , Im not touching the throttle and have foot fully depressed on clutch




audi s3 :: 01122010017.mp4 video by cyrusgsxr - Photobucket

 

[Westy]

Similar to mine mate. Also the smell of fuel would also suggest a lack of spark. I would definitely look at the coil packs first as I went through a load of different things before I replaced the coil packs and it's been spot on ever since.

 

[8YA335TDI1STED]

cheers westle , will vcds diagnose any faulty coil pack ? im planning on ordering it today

 

[Westy]

I think it can diagnose coil packs as far as it'll tell you if one has completely stoped sparking (eg cylinder 2 misfire). When I scanned mine it showed no faults because the coil packs were working but just not as efficiently as they should have been.

VCDS/VAGCOM is something that any VAG enthusiast should own, you'll find it'll come in handy. VCDS was the first thing I bought when I got my S3 and its saved me a lot of cash over the last 2 years.

 

[8YA335TDI1STED]

yeah i bit the bullet and bought a hex usb+can + 3m extension cable from ilexa costly piece of wire @ 264 delivered but at least i know its the pukka Rosstec item so hopefully get this problem sorted out next week

 

[Westy]

I payed over £300 with the import tax from ross-tech but it's helped me out so much. Good luck with fixing this problem.

 

[MartayMcFly]

Only been using my car occasionally with all the snow up here, and it hasn't wanted to start very happily each time. It has a moment of hesitation once it's started, then starts dropping revs as if it was about to stall. I just give the throttle a prod and it seems to recover. It idles at 1100-1200rpm with the heater on HI, the rear window heater on, and the lights on too (though the temp hasn't been above 2 degs for 9-10 days). Once up to temp it settles back to 800rpm though.

Is it not just the temperature, or should I get the battery/alternator checked? Coolant level is fine.

 

[8YA335TDI1STED]

Only been using my car occasionally with all the snow up here, and it hasn't wanted to start very happily each time. It has a moment of hesitation once it's started, then starts dropping revs as if it was about to stall. I just give the throttle a prod and it seems to recover. It idles at 1100-1200rpm with the heater on HI, the rear window heater on, and the lights on too (though the temp hasn't been above 2 degs for 9-10 days). Once up to temp it settles back to 800rpm though.

Is it not just the temperature, or should I get the battery/alternator checked? Coolant level is fine.

did u watch the video link i posted above ? is it the same as my symptoms ? I dont think its just the weather m8 ive never seen this on any other car and its deffo intermittent fault with mine so bound to be some kinda electrical prob somewhere

 

[mmiladinovic]

I've experienced the same problem: difficult start and settles well after a few seconds. Doesn't happen every time tho but its happened in temperatures ranging from -11 to +5 deg C.

I have replaced the temp sensor but the problem hasn't gone away.

Any resolution to this problem?

 

[LD3]

For what it's wort I had this erratic behaviour too and she ended up dying on the M4. The alternator had gone bought a brand new 120amp one off eBay (£125) and she doesn't do it anymore. Not saying it necessarily is your alternator but might be on its way out.

When pulling off or when the wheel is turned near full lock can you hear squeaking? That might be the clutch/belt on the alternator which might need changing

 

[S3KO4]

Alternator pullys are a lot more common on VW tdi such as Golf and Bora. one way to check, is to see if the drive belt tenssioner has any backward/forward movements this indicates pully clutch is worn out. requires special tool to change the pullys and are around £30, still a lot cheaper than a new alternator.

 

[camscockle20vT]

hey dude i havent read all the replys so someone has probly gave u a similar answer. but your car sounds just like mine apart from yours has'nt stalled, so id suggest a full tank of fuel to start as its cheaper than changing all sorts to cure the problem, as it may be your filter,and a full tank aparently helps the pressure if you have a dodgy pump or filter. i only know this because i started a thread about similar problems and had some good suggetions.

 

[Westy]

Have you changed all 4 coil packs as this solved my issue?

 

[mmiladinovic]

funnily enough it started better today with half tank of fuel, outside temp still below zero (am in the Alps). whereas now thinking about difficult starts happened with quarter of a tank or less.

will fill it up and keep an eye on it. if it happens again i will look at replacing the MAF and cleaning or replacing the throttle body.

all 4 coil packs changed about two years ago..

thanks all.

 

[8YA335TDI1STED]

hey dude i havent read all the replys so someone has probly gave u a similar answer. but your car sounds just like mine apart from yours has'nt stalled, so id suggest a full tank of fuel to start as its cheaper than changing all sorts to cure the problem, as it may be your filter,and a full tank aparently helps the pressure if you have a dodgy pump or filter. i only know this because i started a thread about similar problems and had some good suggetions.

i tried all that m8 had new filter fitted at service just 2000 miles ago along with a tin of bgk44 so the problem persisted intermittently for a while , coincidentaly it also had the clutch switch classic signs ie high revs on clutch depress , sure as eggs is eggs i plugged in the vcds cable and it had logged a prob with the switch replaced the switch and now the car has no hunting revs or the bad cold start behaviour also the car feels far more responsive whilst driving, it was a very easy fix no need to remove lower cowling just get an assistant too depress the clutch and fit the new switch it twists about 45 degrees clockwise and locks in place and jobs a good un all rev probs have disappeared but bear in mind i had the car fully serviced b4 changing the switch thanks too all for replies and sujestions :icon_thumright: