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Stuttering on cold start

BobbyT

New member
Hi Everyone, need help with an issue: Have a 2011 Golf with 2.5l auto, sportline. When it's cold (around 0 degrees Celsius - freezing temp.)the car starts but only goes up to around 800rpm then stutters pretty bad as if it's missing, sometimes it will stall and sometimes it won't. Doesn't do it if it's above freezing (around) or if it has been running within the last few hours. So far my mechanic has cleaned the throttle body and checked for vacuum leaks, no codes have been generated and my mechanic says that everything looks fine on the computer (all values look right and no error codes). I've also changed the upper (on the block) coolant temperature sensor with no luck. I'll be changing the lower temp sensor in a day or two. Anyone have any ideas? N80 valve? Fuel filter? Thing is it only happens when it's cold.
 

BobbyT

New member
Thanks for the reply, my mechanic checked and no codes, no dash lights on either. Spark plugs were changed at the dealer about 5000km ago. Only happens when cold, not under load or when damp or anything like that so I don't believe it would be the plugs or coils...
 

MLue1

Drag Racing Champion
At this time of the year you can have frozen condensation freeze in the Air/Oil Separator (AOS) and tear the rubber diaphragm, it will give a symptom very much like when you remove the oil dip stick when the engine is idling. The round cover on top of the Valve Cover can be removed and checked. Dorman sells replacement diaphragms.
 

erichorn10

New member
Had a very similar issue with my 2010 2.5 manual. Only on really cold days, would almost die on startup and shook violently. Car threw a few codes for knock sensors, o2 sensor. Got the sensors replaced and also did an intake/throttle body clean. This did not fix the issue. Took it back to the shop where they then performed a software update that has since seemed to fix the cold start idling issue. I don't have the paperwork in front of me to get the TSB # but can look it up and get back to you on that if you like. But I would have your shop look into this issue and perform the update as it seemed to alleviate the issue for me at least.
 

BobbyT

New member
At this time of the year you can have frozen condensation freeze in the Air/Oil Separator (AOS) and tear the rubber diaphragm, it will give a symptom very much like when you remove the oil dip stick when the engine is idling. The round cover on top of the Valve Cover can be removed and checked. Dorman sells replacement diaphragms.

Just ordered one yesterday, will install and try it out as soon as it arrives.
Thanks!
 

BobbyT

New member
Had a very similar issue with my 2010 2.5 manual. Only on really cold days, would almost die on startup and shook violently. Car threw a few codes for knock sensors, o2 sensor. Got the sensors replaced and also did an intake/throttle body clean. This did not fix the issue. Took it back to the shop where they then performed a software update that has since seemed to fix the cold start idling issue. I don't have the paperwork in front of me to get the TSB # but can look it up and get back to you on that if you like. But I would have your shop look into this issue and perform the update as it seemed to alleviate the issue for me at least.

Actually on another forum a guy who is supposed to be a Master Tech for VW stated that he fixed someone's vehicle with the same issue in 10 minutes by doing an update. If you could find the TSB# that would be great, I'd really appreciate it as my care is out of warranty and if that could help me get the dealer to do it without charge I would be really happy.
Thanks!
 

MLue1

Drag Racing Champion
The only update that I'm aware of is the one for the MAP Sensor update, but I believe if you remove the Throttle Body and the MAP Sensor and clean the oil of the MAP it accomplishes the same thing. The update allows the MAP to operate covered in oil.

I removed the intake manifold on my car recently and it was fairly clean, not much oil in there so prolly explains why mine is OK at 158K km. Not over filling, only putting in 5 litres of oil in at a change may have somethng to do with it as well.
 

erichorn10

New member
The TSB# 2030305

Also I was incorrect earlier as it was my MAP sensor that was replaced and not the O2 sensor like I said before. Throttle body and intake manifold were also cleaned and the problem persisted. Hopefully this solves your issue.
 

CHarmer

Passed Driver's Ed
I too have been experiencing these issues on my 11' golf 2.5 for the last two winters.
Only happens when left overnight in below freezing temps. Most of the time i will have to gently give is some gas to stop it from stalling/dropping bellow 400 rpm. It sounds/feels so rough. But after 10 seconds it puurs. I almost thought my pflo sri was just delivering such cold air it had a hard time getting going. ( noidea )
Some people say turining the key into acc and letting it sit for 20 seconds before startup can help. Over the last month i have been trying this aswell as turning into accesory multiple times and back to off before starting car. It seems to work... but i may be crazy.
NEVER leaves a light on dash.
 

usefulidiot

Go Kart Champion
I posted this same thing a while back....somewhere on the boards.

Mine does it usually after jockey cars in the driveway in the winter. So..i'll switch cars and mine will be shut down after running very momentarily. When I go to start it up after it's cooled down it will twerk and jerk like mofo(at random...maybe 2 or 3 times over the winter).

Same...no codes thrown and everything works its self out. My running guess was it running rich due to cold and startup and then being quickly shut down again. I now try to run it for a few minutes before shutting it down when I'm jockying cars. Who the eff knows ¯\_(ツ)_/¯

Red tops,new NGK plugs, and fuel filter ordered. Treat her to a German Spa Day in a couple of weeks. Just rolled 110K KMs.
 

BobbyT

New member
Update: so just the other day installed the lower temperature sensor and a Dorman pcv valve. Now the car starts almost perfect. It doesn't stutter and revs up to about 1400rpm for a couple of seconds and then come down to about 800 for a bit then about 650. It's strange to me because it seems like it's about to start stuttering but just gets by without doing it, maybe it's me just being over sensitive now. My mechanic who I've been friends with for about 30 years says only thing left is update ECU or air pump. I believe it's air related as I think it's running too rich. Almost perfect now which is a relief
 
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