A3 1.8T - Cold running problems

1. Remove it
2. Clean it with brake cleaner
3. refit it

/ubbthreads/images/graemlins/grin.gif
 
I changed the air temp sensor today, and its made ****** all difference! Really starting to annoy me now! So far i've changed:

Coolant Temp
Air Temp
Coolant Thermostat
Igniton module
MAF
Spark Plugs

Dont know what else it can be!

Rich
 
Swapped air-temp from my passat and doesn't seem to have made any difference, mine has also had the coolant temp and MAF replaced. Still keep getting the (N249) boost valve fault using Vag-com although I don't think this has anything to do with the cold running problem.

Jeff.
 
[ QUOTE ]
I changed the air temp sensor today, and its made ****** all difference! Really starting to annoy me now! So far i've changed:

Coolant Temp
Air Temp
Coolant Thermostat
Igniton module
MAF
Spark Plugs

Dont know what else it can be!

Rich

[/ QUOTE ]

Have you considered the Lambda Rich? Or tried giving the throttle body a clean... just a thought.
 
Just checked mine with Vag-com again as it wasn't running well this morning and had the following error :- 17705 - Pressure Drop between Turbo and Throttle Valve (check D.V.!)
P1297 - 35-10 - - - Intermittent
The car is really beginning to annoy me know !!

Jeff.
 
Replaced the DV which was knackered, but still had the cold running problem, just removed the throttle-body and cleaned and the car feels like a new car. Hopefully this will have cured my cold-running problems, will update when i've used it for a few days.
 
Just for your info...I posted a while ago that our Golf 1.8T (AUQ) had cold running problems. Lumpy and jerky when initially setting off etc.

At the weekend I finally got round to doing some tinkering.

1) I disconnected the MAF and went for a drive, with the car cold. Car was smoother. (So we may need to change the MAF)
2) Decided to do some cleaning. Disconnected the intake pipe to throttle body. Squirted some Wynns Carb/Injection Cleaner in there, and wiped out the oil residue. It was pretty clean to be honest.
3) With intake pipe still disconnected. Switched ignition on, but DID NOT start the car. Put something heavy on throttle peddle to open up the TB butterfly valve a bit. Squirted some more Wynns in. Waited for it to dribble out and wiped inside. Being careful not to touch the TB butterfly valve - didn't want to damage the electronic actuators etc. Then switched off the ignition, wiped around again, and then reconnected the intake pipe.
4) Disconnected DV (standard 710N). Noticed it was quite oily. So squirted some Wynns in there too. What the hell. Let the oily gunk drain out and let it dry off.
5) Re-fitted DV.
6) Started car, and let the intake temps get up to about 80 degC. Then stopped the car.
7) Disconnected turbo intake hose from MAF. Started engine. Squirted 1 shot of Wynns into the intake and waited for around 30 seconds. Repeated this about 5 times.
8) Reconnected intake hose to MAF
9) Removed MAF sensor with Torx Security socket (TX25, 5 star pointed). Cleaned MAF with IPA solvent. Let it dry a bit. And then reconnected.
10) Cleared MAF fault code (because I had run the car with it disconnected)
11) Started car and let coolant temp get back to about 80 degC
12) Stopped car. Did a Throttle Body Alignment.

So far, when driving the car from cold it has been better. I'll let you know if the problem returns.

AL
 
Well mine is getting worse. You can use ANY power, even just really gentle acceleration, and it misfires like a b*tch!! Horrendous. It lasts about 3-4 mins, and then is fine!

i get a coolant warning every morning when start it up...Coolant level is fine! Also this problem of car not getting upto temperature... I'm not sure what is going on, but its annoying me!

Rich
 
I think the max line in the coolant bottle isn't right rich, sinse I topped mine upto about 5-10mm above the max line it's never come on even in very cold weather (I topped it up with the correct audi stuff)

No clue on the other problems though - you've tried so much, worth getting it to a rolling road (with vagcom etc) when cold maybe?
 
audi upgrades
Im going to do some logging of injector openings, and ignition to check if its not sparking, or not fuelling when its missing... Its really bugging me! Will also log throttle position

Defo not a power problem when its warm...

Rich
 
Update on my golf (aum engine). Had the same almost undrivable cold hesitaion.

I've now replaced both the lambda probes with the US sourced items (cheers Rich for the excellent price on these).

The post cat one is a real squeeze to get to and having the proper tool is a must!

Anyways, the hesitation has not returned so far after a few days of driving. Also the check engine light hasn't appeared, and no error codes.

Hopefully this is the end of it for my car.
 
Kev,

Will be interesting to see if this cures it. Mine had not done it in a few days now - Milder weather i believe! So if mine does it, i'll let you know.

Rich
 
Despite my cleaning efforts above, our Golf has gone back to its cold running problems. Jerky when initially setting off, uneven idle - rev counter needle doesn't move much, but car seems to be idling unevenly. So much so, you can feel the uneveness through your seat.

AL
 
I'm signing off my problem as cured now. Car has been fine for over a week and a half. No returing errors or running issues.

Car is more responsive and fuel economy has improved now the ecu has adapted.

Interestingly the car had a "pressure loss between turbo and TB, check DV" error which I couldn't solve either. Had checked everything.

This error has also not returned since I fitted the new lamda probes. Not sure how its releated, but I'm not complaining!
 
Intresting, I have the same problem with cold running and the same pressure loss error, but I have already changed the diverter valve and still getting it.

May be worth trying how much was the part and were from?
 
How do you test if your lambda probes are working correctly? I still havent got to the bottom of my cold running issues. Changed so far....DV, MAFF, Two temp sensors, cleaned throttle body. The next thing i was gona try was replacing the lambda probes.
 
Depending on the year/engine code of the car, you run though a bunch of tests via VAG-COM to asertain whether the probe is delivering the correct voltages and at the correct speed. Also lambda probe heating is checked.
 
Thanks, any idea where to go and how much it should cost to get these checked out. All i know is its the drive by wire if thats any use.
 
Hi just to add my two cents my car also had cold running problems. It turned out that one of the lamba sensors somehow came loose from its bracket and was touching the exhaust.

This caused the lamba sensor wiring to burn due to the heat of the exhaust and was causing erratic idle and poor running problems.

Hope that helps
 
My car is still having problems. Changed lambda probe too and this still has not helped. It seems to be OK once car is above 45oC or so collant temp (on climate display)...I'm stumped as to the problem!

Does anyone know if and where a oil temp sensor is? I think that its a possibility that is my issue... but i need to find it.

Rich
 
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