Frage Scheitern an ASU | Posts 16+

Okay, when I say the catalytic converter is "clogged," it doesn't mean it's completely blocked and nothing can pass through, because in that case, the engine wouldn't run at all. "Clogged" means that out of, for example, 200 channels within the catalytic converter that are supposed to allow exhaust gases to pass through, only 100 or fewer are actually open, while the rest are blocked with soot. This makes the car feel sluggish and difficult to drive. It's a bit like someone slowly squeezing your throat, making it increasingly harder, and eventually impossible, to breathe.

THANK YOU Tobi, a very good explanation! Why can't I come up with that myself? Brilliant about the choking on the neck . Hopefully now he understands what we mean!

"Please secure the cat, preferably by putting it in a carrier for transport."
"With the white one?" But that has nothing to do with smoke if it's supposed to be a cat!
If it's clogged, the air mass in the higher RPM range will also decrease when power is required.
Because remember:
Where nothing comes out, nothing can go in. And if too little air mass is reported, the engine control unit (ECU) saves on diesel fuel.

Okay, let's see what they find on Tuesday first. I'll tell them what to specifically look for. Sometimes those guys don't figure it out on their own... or they just don't feel like it.
But that would be bad, because I'm bringing the car in so they can identify the problem .
Well, let's see .

Okay, so today they performed a guided troubleshooting process. The error message always says: "Charge pressure control exceeds regulation limit."
According to the software, there is a "transition resistance in the cable run." It should be fixed with a "repair kit for temperature sensors."

I don't think that's the right approach... They probably didn't even check the valve timing etc. because, according to the mechanic (who is a master technician), it could also be related to those things based on the symptoms!

What do you think about this? Is the engine control unit (ECU) receiving incorrect information from the temperature sensor? Could that be why there's so much exhaust smoke and increased fuel consumption?

It looks like there's been another misdiagnosis.
According to TPL, certain error codes, including "16618 P0234 Boost pressure control exceeding limit," indicate a transient resistance in the engine wiring harness that affects signal values from the boost pressure sensor and/or the mass airflow sensor (MAF).
A repair kit for the temperature sensor wiring is offered as a solution, which is then installed between the engine and the MSG (Main System Module).

Now, the technical specification also states that as a troubleshooting step, you should check parameter MWB 10 in the engine control unit.
MWB10 displays the following values: Air mass (mg/h), Atmospheric pressure (mbar), Actual intake manifold pressure (mbar), Accelerator pedal sensor value (%).

Fields 2 and 3 need to be checked.
Please check if there is currently an increased signal deviation. To do this, simply turn on the ignition, select function 01 self-diagnosis, and in measurement block 10, check whether you can observe a deviation greater than 50 mbar in display fields 2 and 3.

Now I checked using VCDS, but I can't find any deviations.
The atmospheric pressure and the actual boost pressure are definitely equal; very rarely, there might be a deviation of 10 mbar.

What am I supposed to make of this now? Did the mechanic not understand their job, or am I just too stupid to get it?

Yesterday, I used VCDS to check the operating temperatures of the engine while it was cold (the car had been standing for at least 7 hours).
According to the labels, the temperatures should be approximately ambient temperatures. The outside temperature was degrees Celsius, the coolant temperature was 10.5 degrees, and the fuel temperature was 7 or 8 degrees Celsius.
Therefore, there is a significant discrepancy in that area.
When the engine is warm, the coolant temperature never exceeds 80 degrees Celsius. It always stays within that range. The highest I've ever seen it go is 83 degrees, but never above 85.

No matter which driving profile I use, could the high fuel consumption be due to this? Is it possible that the engine control unit (ECU) is always operating at a state close to "full operating temperature," causing it to inject too much fuel or operate in an "unoptimal" way?
What do you think? Could it be just a faulty sensor, or could it also be symptoms of incorrect valve timing?
This problem seems to be becoming increasingly "insoluble."
If I had a stage and the necessary tools available, and could be without the car for longer, I am certain I would figure out how to get it back on track.
But as you can see for yourselves, when dealing with VAG workshops, one becomes an easy target.

After you measured the temperature, did you start the engine? I hope not! Seven hours is probably not enough time for the engine to cool down completely, so there's residual heat of 10°C. The fuel consumption issue is likely not due to a faulty temperature sensor; it's different with gasoline engines. Since the dealership mechanics are apparently too incompetent to properly check the lambda sensor, try logging the lambda sensor readings while driving at full throttle in 4th gear between 1500-4000 RPM several times! Don't forget to also log the mass airflow sensor data.

Hey, how many kilometers does your taxi have on it anyway? Taxis don't drive very little, you know.

Yes, yes, the "nice" ones. Although I presented them with the facts, I couldn't convince them. The manager said: "Don't get hung up on the values... The engineers know exactly what they're doing."
Haha. The engineers, yes, but unfortunately not the mechanics. It's sad that they don't even know how to use a torque wrench.
According to TPL guidelines, the pipeline should only be replaced if there is a deviation greater than 50 mbar.

It's a shame they still won't listen... it's actually pathetic and embarrassing.

The taxi is 2 and a half years old and has approximately 205,000 kilometers (or miles) on the odometer. I've been experiencing this problem for about 80,000 kilometers (or miles).
So, it's not a sign of old age .

I've uploaded a log file. While it wasn't explicitly recorded for this purpose, it contains current values that I obtained during a drive on the highway.
Hopefully, you can make something out of this.
Otherwise, I'll need to run the test at speeds between 1500 and 4000 rpm when I have some time.
/viewtopic.php?p=145431#145431

Regards,

Serdar.

Hi,

serdarg wrote:

The taxi is 2 and a half years old and has approximately 205,000 kilometers (or miles) on the odometer. I've been experiencing this problem for about 80,000 kilometers (or miles). So, it's not a sign of old age .

And you actually managed to get 205 million kilometers on your car?
Or did I just make a mistake in my calculation? Isn't 205,000 thousand equal to 205,000,000?
*duck and cover*

Regards,

Kusi.

That doesn't help me either.

The G31/G42 cable has been replaced, and as suspected, it didn't make a difference.
It's sad when you can't even expect experienced and skilled mechanics and master technicians at the VAG group to be able to properly read and understand their technical publications.

According to my assessment, the vehicle has a temperature issue. The average coolant temperature is between 75 and 80 degrees Celsius, but it briefly reaches 84-85 degrees Celsius under load.
Ideally, the temperature should be at least 87-90 degrees, but that is not happening.
I'm going to start a new thread about this. It could be the G62, G83, and/or the thermostat. What might be broken?

Unfortunately, the log is not in the format 3-8-11 and it's much too long!
It's definitely not the temperature. Try driving a different car with the same engine; it will stall when cold just like yours does. During the emissions test, the vehicle and air conditioning are turned off, and even with multiple full-throttle bursts, the engine easily reaches temperatures above 90°C because there's no airflow.
Disconnect the hose at the intake manifold near the EGR valve and shine a flashlight inside to see if it's clogged with carbon deposits from the EGR.

"I should take a look inside the intake manifold. So, the problem is more about fuel consumption than performance."
I also think that I'm driving more cautiously because of the high fuel consumption, and that's why I have a subjective feeling of reduced power.
As I mentioned before, what bothers me is that the engine is consuming more fuel. However, the increase is rather gradual.
At first, I could drive it around the city with 7 liters of fuel, then it became 7.5... eventually 8.5, then 9... and now I'm averaging 9.5-10 liters.

"Back then, I never really paid attention to the coolant temperature readings, but I seem to recall it being around 85 degrees Celsius on average, sometimes even 90. Now, during normal driving, it's between 77 and 80 degrees, and at maximum load, it reaches a maximum of 85 degrees."
And there simply has to be a connection somewhere...

Disconnecting the hose from the air intake manifold takes just a minute! A completely clogged air intake manifold can cause high fuel consumption and reduced power, while also producing more smoke from the exhaust. What's stopping you from taking a quick look?

Perhaps this explanation will help a little... above is a section of it.

Without being a self-proclaimed expert, it seems to me that the turbocharger boost pressure is not correct.
Let's take a look at the rate of change in speed between 160 and 180. The speed is increasing almost constantly, but the LD (presumably "load") is still decreasing.

"Stuck VTG?" or "Problem with the VTG?" (assuming VTG refers to a specific device or system).

Perhaps someone with more expertise will chime in...

The SETPOINT is missing! Unfortunately, there's nothing we can do with it like this. The article provides detailed instructions on how to proceed! }