Very long crank (after sitting for 4+ hours) at cold temperatures 2011 A4

[Mwad7]

Hey guys! Bought my 2011 A4 last December. Bought at 96000km and had an android head unit installed on the same day.. The issue started 2 weeks later.

Previous owners put 87 in it for 10 years. ive been putting obly 91

Only happens when temp is sub-5 degrees celsius after the car has been sitting for 4+ hours.

Only codes showed were p0300 intermittent misfires occasionally but car runs great once its on.

Took it to 4 mechanics (including Audi).

2 said nothing was wrong and the other 2 tried all the following:

- replace all sparks and coils
- replace all 4 fuel injectors
- replace engine air filter
- replace fuel filter


Car doesnt have oil consumption issue (had stage 1 fix under a recall under previous ownership).

Timing chain not done yet.

- engine oil interval is 10000km under my ownership as I do lots of highway driving

Car is now at 126000km. Issue has persisted since.


Any ideas?


Heres a recent scan on obd11 but was aftee a recent incident where i barely had any fuel left.


https://we.tl/t-VTLLGoJM8S

[audrobotic]

Results of measuring timing chain stretch via cam phaser adaptation?

[Mwad7]

Hey bud, not sure how to do that, would OBD11 tell me that as well?? Why would the timing chain cause that to happen only when the weather is cold? :S

[Mwad7]

Edit:

Forgot to mention that the battery was replaced in 2019 at Audi and that we also tried throttle body cleaning and carbon cleaning. No dice.

[audrobotic]

Not sure why it would be specific to very cold temps, But long crank is one symptom of timing chain problems.

The cam phase adaptation can be logged from vagcom. I hope at least one of the four mechanics looked at that. (One audi shop I went to provided that value without me even asking, just part of routine oil change, because its such a big deal on these cars). It basically a big clue regarding your timing chain tensioner and chain. (tensioner extended and/or chain stretch).

[Mwad7]

Not sure why it would be specific to very cold temps, But long crank is one symptom of timing chain problems.

The cam phase adaptation can be logged from vagcom. I hope at least one of the four mechanics looked at that. (One audi shop I went to provided that value without me even asking, just part of routine oil change, because its such a big deal on these cars). It basically a big clue regarding your timing chain tensioner and chain. (tensioner extended and/or chain stretch).

Will check, thanks I'm already planning on getting the chains done at around 135k but ill have a look. You think i can see that on OBDelevn?

[audrobotic]

I dont know a whole lot about odb11 but think you can check cam phase?

https://m.youtube.com/watch?v=YtTOGP...ature=youtu.be

[Theiceman]

Sounds to me like you are not getting cold start enrichment or you are carbon clogged. Did they do a carbon clean when they did injectors ?
I'd have a look at what the car is reporting as temps when it's cold.

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[Mwad7]

Sounds to me like you are not getting cold start enrichment or you are carbon clogged. Did they do a carbon clean when they did injectors ?
I'd have a look at what the car is reporting as temps when it's cold.

Sent from my SM-G973W using Audizine Forum mobile app

Hey bud! Not sure what you mean by cold start enrichment, can you elaborate?

Yes carbon cleaning was done as well and the throttle body was cleaned.

[Theiceman]

All cars have a richer mixture to start when cold.. then lean it out as it warms up. It's like the old choke
Modern cars monitor coolanf temp. If it's reporting wrong temp then it won't enricjen it. Something to check.
Other guess would be hpfp.


Sent from my SM-G973W using Audizine Forum mobile app

[Mwad7]

All cars have a richer mixture to start when cold.. then lean it out as it warms up. It's like the old choke
Modern cars monitor coolanf temp. If it's reporting wrong temp then it won't enricjen it. Something to check.
Other guess would be hpfp.


Sent from my SM-G973W using Audizine Forum mobile app

Okay okay. I have a new finding to report. So my car took over 10 minutes to warm up this morning and was running rich (-2degrees outside) and when i stopped at a light for a bit the temperature gauge dipped to a quarter of the way then it went up to operating temperature when i started moving again!

Thoughts?

Thanks for all your help bud!

[StuckAntichris]

New data is always good. In terms of the long warm up time that sounds like a stuck thermostat. I think you can replace that without replacing the water pump but honestly since you would be that far anyways it would probably be a good idea to just replace it anyways since they fail so often.

In regards to the temperature dropping at the light, that sounds like you might have air in the system, or the temperature sensor (that's located in the water pump housing) might be going bad. Another easy replacement if you have to go that deep.

Hope this helps

[Theiceman]

yeah cant be a coincidence that your temp is all over the place and it uses that sensor for cold start ... i think you are on the right track. i wonder is you are getting an air pocket around that sensor and its fooling the car..

I would replace it all , pump/ sender/ stat.. its all one assembly.

[MyDimeIsUp]

yeah cant be a coincidence that your temp is all over the place and it uses that sensor for cold start ... i think you are on the right track. i wonder is you are getting an air pocket around that sensor and its fooling the car..

I would replace it all , pump/ sender/ stat.. its all one assembly.

If the coolant was drained and refilled recently I would drain coolant, create a vacuum in the cooling system, and then refill and see what happens. If coolant wasn't drained recently then I'd say go for the water pump off the bat.