Hot Start Problem and White Smoke

[Nathan Bailey]

So I have a 2008 reg Audi A3 1.9tdi (BXE) with 138k on the clock and everytime I go to start it up when it is at temperature it takes a while to start up, around 10 seconds, but when its cold it will start up straight away. Recentley it has had the same problem even when its cold but its not very often it happens when its cold, once the engine starts up it runs fine doesnt miss a beat but it also has a lot of white smoke coming from the exhaust. It has recentley been serviced but hasnt got any better.

 

[eLeCtRaSh]

I got camshaft position sensor bad which makes problem with hot start and start in general. tomorrow i got it replaced so it should fix.
I will let you know

 

[Nathan Bailey]

I got camshaft position sensor bad which makes problem with hot start and start in general. tomorrow i got it replaced so it should fix.
I will let you know

That makes sense tbh haha thanks for the update

 

[HHS3]

I got camshaft position sensor bad which makes problem with hot start and start in general. tomorrow i got it replaced so it should fix.
I will let you know

Can you let me know how you get on please bud?

I've have had the coolant temperature sensor changed previously and the crankshaft position sensor done last week but still have the odd start up issue (http://www.audi-sport.net/xf/threads/2007-s3-tfsi-8p1-hot-start-up-issue.261727/#post-2665941). The camshaft sensor is the next thing on my list to try as after that I've read it's either the battery or start motor (both due to incorrect crank speed).

 

[SootySport]

The white smoke doesn't sound to good, usually signs of head gasket or turbo on their way out.

 

[Nathan Bailey]

The white smoke doesn't sound to good, usually signs of head gasket or turbo on their way out.

Thanks for the reply.
Ive noticed recently the waste gate on the turbo isnt as loud as it used to be I can barley hear the whistle anymore where as before it started to smoke it was really noticeable, do you think this is a failed turbo?

 

[HHS3]

I got camshaft position sensor bad which makes problem with hot start and start in general. tomorrow i got it replaced so it should fix.
I will let you know

How has your car been since having the Camshaft Position Sensor changed a few days ago? I've got mine booked in to have this done on Friday.

 

[shadow1993]

isnt white smoke put out when the engine is burning coolant? coolant leaking sumwhere, me thinks.

 

[SootySport]

isnt white smoke put out when the engine is burning coolant? coolant leaking sumwhere, me thinks.

Yes, coolant or the turbo spewing oil. Or even lots of condensation but depends how long it does it for and how often the car is driven.

 

[Nathan Bailey]

The white smoke has stopped now, i wasnt loosing any coolant or oil i think the smoke was a result of the egr and turbo clogged up with carbon as i gave them both a good clean including the pipes and now it hasnt smoked one bit! I also drive the car daily around 60 miles a day!

 

[SootySport]

Odd it was white smoke then, maybe a tinge grey going on there
How did you clean it?

 

[desertstorm]

White smoke on a diesel when it's cold can be due to duff glow plugs or a coolant temperature sensor fault. The glow plug activity is controlled by the engine temperature, If you try and start a diesel when it's cold and one or more glowplugs don't work unburnt diesel can find it's way into the exhaust where it vapourises and comes out as white smoke.
Of course there can be other reasons but check the coolant temp sensor and glow plugs.

 

[Nathan Bailey]

Odd it was white smoke then, maybe a tinge grey going on there
How did you clean it?

Sorry for the late reply but used braked cleaner on the egr and used the mr muscle trick for the turbo.

The past few days the smoke has came back again really bad not sure what to think now. I have switched from using fuel from the supermarket (asda) and am now using shells nitro diesel stuff but i dont think that would make any difference

 

[Nathan Bailey]

White smoke on a diesel when it's cold can be due to duff glow plugs or a coolant temperature sensor fault. The glow plug activity is controlled by the engine temperature, If you try and start a diesel when it's cold and one or more glowplugs don't work unburnt diesel can find it's way into the exhaust where it vapourises and comes out as white smoke.
Of course there can be other reasons but check the coolant temp sensor and glow plugs.

Thanks a lot for the info i will try that next weekend! Already replaced the temperatue sensor about 1 month ago but theres also one on the radiator do you think that will need to be replaced as im led to believe that only controls the operation of the fans? Thanks

 

[desertstorm]

As you say the one on the rad controls the fans. Have you checked the glow plugs are good?. Does the glow plug light come on for several seconds when it's really cold ?.

 

[Nathan Bailey]

As you say the one on the rad controls the fans. Have you checked the glow plugs are good?. Does the glow plug light come on for several seconds when it's really cold ?.

Hello, i havnt checked the glow plugs but the light doesnt stay on for long when its cold maybe 2-3 seconds