2.0 TDI 16V A3 - Starting problems and rough idling

Hello everyone,

I'm having a problem with my Audi A3 2.0 TDI 140 hp, manufactured in 2007, with 150,000 km on the odometer.

The engine is difficult to start when cold (in summer temperatures), taking about 3 seconds. However, once it starts, it runs quite well. When it's warm, it misfires at low RPM (up to approximately 2000 RPM) and under heavy load. If you briefly ease off the accelerator and then press down again, the jerking often stops.

"The error memory is clear, the EGR valve has been checked and cleaned, and the EGR cooler was replaced due to suspected leakage. The MAF sensor readings are correct." Removed the PD elements today... hmm, they look strange. Does anyone have any ideas what the reason might be? (Pictures)

"Do you think the nozzles and the head are finished? Or what do you think?" What is the cause of this wear pattern?

Ah yes, this is what all 4 nozzles look like...

Regards,
Okay, please provide the German text you would like me to translate into English.

What does the cone in the cylinder head look like, is it oval? Normally, it misfires when the seal between the injector nozzle and the combustion chamber no longer fits properly.
I would have also seen it in the MWB 23.

Hello,
Sorry for the question, but what is MWB 23?

What is the switching time variation of the PD elements?

Hello.
To me, the nozzle looks quite normal. Slight erosion above the first sealing ring, but no significant damage.
I can also see no defects in the piston ring area. At least not in the picture.

You mentioned that the AGR cooler was replaced. Did the engine lose any coolant? Perhaps the problem wasn't the cooler itself, but a hairline crack in the cylinder head. The first 16V cylinder heads, which were not manufactured in Germany, had significant problems.

Are the values of the idle speed control system within the acceptable range?

Hello,

PDE wiring harnesses would also be a possible option! Check the wiring harness connector for oil (mine had some oil on the contacts).
At my mileage (307,000 km), I probably had all the sensors (coolant, diesel, camshaft) replaced some time ago...
My wiring harness, despite having 300,000 km on it, seemed fine, but I still decided to replace it.
I never kept my carburetors outside. With the 16V model that has a double flange, the problem should be less severe, unless it was always run at full throttle...
For a 2007 model, the head should also be in good condition! (My opinion)
Twin-plunger pump: Have you ever measured the pressure? With this, you could test two sides simultaneously.
Does he have a tuning module or something similar installed?
I generally replace the LMM (lambda sensor) every 150,000 km with a brand new, original part.
EGR throughput checked?
Checked the intake manifold for excessive carbon buildup?
Just try starting it without waiting for the glow plug indicator to go out... mine NEVER takes 3 seconds - however, it starts better overall in the cold during winter...

SG

Hufe wrote:

Hello. I can also see no defects in the piston ring area. At least not in the picture.

You can't see the seat in any of the pictures either.

alevuz wrote:

Hello, I never kept my carburetors outside. With the 16V model that has a double flange, the problem should be less severe, unless it was always run at full throttle...

Specifically, the 16V models with the double thread and conical sealing surface tend to cause more problems because the sealing surface becomes oval, which then leads to these jerking issues.

Please take another look at the valve seat at the top, or take a picture where they can be seen. Or you can rebuild everything, check the idle speed control as @Hufe suggests, and look at the MWB 23 during acceleration.

Hi, here are the photos. They're not ideal, unfortunately, but I think you can make out what they are. Could do better tomorrow.

chli1976 wrote:

Specifically, the 16V models with the double threaded connection and conical sealing surface tend to cause more problems because the sealing surface becomes oval, which then leads to these jerking issues.

Good morning.

Thank you for the tip!

SG

I would say that in the first picture, the seat is no longer perfectly round.