TDI rough idle on start up

Hi folks
i have owned my A2 for 4.5 years ,1.4 tdi , its been fantastic little car and has been faultless .... well until now !
After a 150 mile trip on the weekend i turned the engine off and left the car for 7 hrs or so .It was a hot day . On returning to the car , on start up the engine started straight away but sounded rough, as if it was running on 2 cylinders . After moving off and driving slowly for a minute or so it was fine and idling as it should . This now happens every time i start the car , same symptoms , no firning problems , it fires straght away . No warm start problems at all

Any suggetions

thanks in advance :)
 
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Thanks for the replies guys
i have vagcom on an old laptop , i will plug it in tonight and see if it throws any codes up .

is there anything specific to the start up process , i started it this morning , same thing but after 30 seconds on the move its running as it should with a nice smooth even idle ?



Mark
 
Probably one glowplug not working. Not an issue starting when the wether is warm, but the cylinder affected will misfire until it warms up.

Does it happen on hot retsrats? If so, not a glowplug.
 
Probably one glowplug not working. Not an issue starting when the wether is warm, but the cylinder affected will misfire until it warms up.

Does it happen on hot retsrats? If so, not a glowplug.

Thanks
I did suspect glowplugs , no problem with warm/hotstarts at all , just initial start up from cold , once moving or higher rev's for 30 seconds all ok .

The glowplug light on the dash goes out straight away though ?

Would vagcom show this up specifically or would it just identify misfire ?

is glowplug changing a simple/diy job ?

Mark
 
Glowplug light just says the relay is working and current is flowing. Doubt VAGCOM would show it up.

Replacing glowplugs and testing them is easy on most diesels but depends on access. If access is easy, just remove, test with a live feed and see if it glows.. (warning hot: take precautions!).

No idea on A2 sorry.
 
I didn't think the glowplugs would be lit up at all in the summer? (i.e., I thought they were only given current in winter conditions?)
 
I didn't think the glowplugs would be lit up at all in the summer? (i.e., I thought they were only given current in winter conditions?)

Exactly, glowplugs shouldn't be lighting at all in the summer weather. Hence my suggestion of the injector wiring harness.
 
Not at first no - when mine went it was an intermittent fault at first, but it gradually got more frequent over a few weeks until it got so bad that the ECU threw a load of error codes and warning lights on the dash and then tripped into limp-home.
 
Not at first no - when mine went it was an intermittent fault at first, but it gradually got more frequent over a few weeks until it got so bad that the ECU threw a load of error codes and warning lights on the dash and then tripped into limp-home.

i see , so was yours just happening at cold start ups to begin with ?
 
Update ..

well apart from the three days of the rough start up the fault have dissapeared , i dropped it at my local garage (non vag) , they could not re-create the fault , i left it with them over night to try a start from dead cold and nothing , it's running fine , they checked all the visible cables etc and suggested it could have been some dodgy deisel ?

I will keep an eye on it and have it checked by my vag friendly garage regardless before the winter set's in .

thanks for all your suggestions :)

i will tell my garage when it goes in to perhaps point them in the right direction
 
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