Cold Start Problems 2.0 TDI - Troubleshooting

Hi,

I drive an Audi A4 B7, manufactured in 2006 (model year 2007), with a 2.0 TDI 140 hp 8V engine and the original DPF (engine code: BPW).

'For the past few weeks, I've been experiencing severe starting problems. When I try to start the engine for the first time, it immediately shuts off again, even after allowing it to preheat for 1-2 seconds. It seems to start, but then immediately dies.'
On the second attempt, it stumbles forward before finally running properly after 2-3 seconds.
It only happens when the engine is cold; once it warms up, it starts without any problems.
Mileage is 140,000 km, mostly long-distance driving. Occasionally, the DPF (Diesel Particulate Filter) needed to be regenerated through a forced regeneration cycle (yellow light illuminated in the instrument cluster).

Today, I connected my VCDS diagnostic tool and read an ash content value of 41.
Über Google habe ich rausgefunden, dass der Grenzwert für den Austausch bei 40 liegt! SDoes that work?

Here are two screenshots:
http://stefan.localh0rst.net/albums/album02/aschewert.jpg

http://stefan.localh0rst.net/albums/album02/DPF_Druck.jpg

Do you have any idea what might be causing the cold start problems?


P.S. My dad has the same engine with a DPF (BPW), but with Multitronic transmission. It has 200,000 km on it, and he hasn't experienced any starting problems.

How much ash is in your dad?

60 is AscheMAX - hover your mouse over the field, and a speech bubble will appear.

m;

My dad was around 20 pounds heavier a few weeks ago.

What's strange about mine is that two months ago, the value was 12, and then it suddenly jumped up to 41.

What is the part number of the differential pressure sensor you have?
Maybe he's had a drink.

12 grams is not enough.
Your dad probably already has a new DPF if it weighs 20 grams.

And always remember not to confuse ash content with loading.

"Load" refers to the value that gets reset to 0.0 during a regeneration process.
What remains is ash, which slowly rises.

The value 063.3 represents the ash content, which is the difference between the estimated consumption and the "measured" value.

+7.9% is quite a lot, which means you are consuming significantly more than the MSTG anticipated.
I see -5.5% there.

m;

The car also consumes a lot of fuel (6.5-8 liters).
Last regeneration was 260 km ago.

As far as I know, my dad hasn't put in a new filter yet, but I'll ask him again.

I understand the difference between loading and ash content. The loading can decrease to approximately 1.x% during the burnout process.
My dad is almost failing.

I misread it.

A learning rate of 0.0 is acceptable; this corresponds to the predicted 7.0 liters.
That's not much - the DPF just eats it up.

The fact that you're only getting readings down to 1.x suggests to me that it's more likely a differential pressure sensor.

VW had a workshop campaign where they replaced the ...A sensor.

m;

Are the shots being fired without a target?
The differential pressure seems too high to me.

I once had a pressure of 8 mbar at a filling level of 18.8%.

Thank you in advance for your help.

How do I extract the temperature reading from the sensor?
Do you want to buy a car?

Remove the lid.

Here he is, working on the 2.0-8V-DPF engine.
http://tequila.homeip.net/Passat/BMP_DiffDruck.jpg

m;

ok...thank you.

I'll check that out. Was the same engine used in the 3C? But I believe the engine code (MKB) is different.

P.S. Yes, the shots were idling. In some cases, the differential pressure reading was around 5.

In the 3C model, the 2.0 8V DPF engine, known for its oil consumption, is referred to as "BMP".

What does the differential pressure reading say when the engine is not running? I would expect it to be very close to 0.0.

m;

As you probably guessed, it shows exactly 0.0 when the engine is not running.

Can the sensor data be read out? I'm not sure how to remove the engine cover right now.
'If things don't improve, I'll take it down first thing tomorrow morning.'

VW covers from recent years are only snap-on.
Simply pull up.

For the Audi, it should be the 07Z 906 051 A - which was also available without the "A" as a previous version .

Maybe just try swapping them out - first, try swapping them with your dad, and if that doesn't work, you can always replace them.

m;

The cover is screwed on.
3 screws, just finished working on the car.

I need to take some time tomorrow to properly disassemble that thing, and then I'll post the results.

How will I know if the sensor my dad installed is working correctly? Probably by the lower differential pressure and the loading coefficient after the initial burn, right?

Okay, I'll do a forced burn test with the sensor from my dad's equipment tomorrow and see what results I get.
Thank you for your help so far http://www.show-and-shine.at/show/images/smiles/icon_question.gif.

"Not until tomorrow?"
Why not now?
http://globetrotter.de/de/shop/detail.php?mod_nr=fen01023

I don't have any tools here at my girlfriend's place to unscrew it .

I actually have a LED Maglite here, but the cover is really stuck on tight. I tried to pry it up a little, but it didn't really budge.

P.S. I just checked. The sensor costs €44.33, but with Nora's discount, it's only €36. That's really cheap. If I don't have the A-version installed, I'll definitely replace it as a preventative measure.

Okay, I'll agree with Martin's diagnosis; it also seems to me that the differential pressure is too high.

You could also try taking a walk with forced regeneration.

Then the loading value MUST be set to 0.0%, otherwise something is definitely wrong.

Then, he should also adjust or recalculate the ash content accordingly.


"Unfortunately, concrete information about the DPF system is still scarce, and it's still somewhat unclear how the measurements and calculations are performed. The above are our experiences so far."