ARL Fails to Meet Lending Target

Hello,

I'm having the following problem.

My turbocharger isn't reaching its maximum boost pressure of 2500 mbar. It accelerates fine, but not with full power, and only starts to produce significant boost at engine speeds above 2300 RPM.

I immediately created a log because I was already on the highway. I accelerated from approximately 1500 RPM to 3500 RPM in 6th gear.

Was mir auffällt ist das im gegensatz zu anderen LOG´s hier im Forum das Tastverhältnis des N75 bei mir bei Vollgas weniger wird. Es bleibt dann bei 29,9% stehen. Ich dachte immer das 100% volle Ansteuerung bedeutet. Was andere LOG´s bestätigen. Die The percentages are increasing.
Is mine different? Unfortunately, I don't have any older logs from mine to compare it to.

Could someone please take a look at the log?

Tomorrow, I'll start looking for the source of the standard errors. I'm ruling out a leak in the LD line for now because 1. I just replaced all the hoses recently, and 2. I know what that sound is when there's a leak. Also, it's not triggering the emergency mode.

Here's what's new in the last 2 years:
Exhaust system including catalytic converter (now a Bosal unit that is only half the size of the original).
N75 (once broke down while I was on the highway).
Hoses from the turbo to the intake manifold, including the pressure pipe (PVC pressure pipe burst about 8 weeks ago at the seams).

The AGR has been sealed with a metal plate for years.

Thank you and best regards.

Quote:

Volkswagen Golf 4 GTI TDI, ARL engine, series 296,000 km.

Respect that nothing else has changed yet; it's only a matter of time before things start happening.
I can also create a log with the standard performance settings for comparison. Is the EGR valve okay, and do you have any error messages related to it?

charlyfirpo wrote:

Was mir auffällt ist das im gegensatz zu anderen LOG´s hier im Forum das Tastverhältnis des N75 bei mir bei Vollgas weniger wird. Es bleibt dann bei 29,9% stehen. Ich dachte immer das 100% volle Ansteuerung bedeutet. Was andere LOG´s bestätigen. Die The percentages are increasing. Thank you and greetings

.
The fact that your key press ratio behaves differently than what you're used to seeing in other logs is...
not the cause, but the consequence of your boost pressure problem.
"Near 100%" means (for your engine) that the turbocharger boost pressure adjustment is moving towards...
"VTG is open," which means the boost pressure is being reduced. In the area of 20%, it should...
By setting the "VTG closed" position, the boost pressure can be increased.
As the engine speed increases and you apply full throttle, the boost pressure automatically increases due to the...
high exhaust gas flow, therefore the VTG (variable geometry turbine) must be gradually adjusted to increase its opening more and more.
The valve is driven in the "open" position, and therefore the duty cycle normally...
gradually increase.
However, even at higher engine speeds, your turbocharger is not achieving the desired boost pressure.
Therefore, the duty cycle remains low.

Best regards, Klaus.

RedR32 wrote:

Quote: Volkswagen Golf 4 GTI TDI, ARL engine, Series 2, 296,000 km. Respect that nothing else has changed yet; it's only a matter of time before things start happening. I can also create a log for comparison, using the standard performance settings. Is the AGR valve okay, and do you have any error entries related to it?

No, that's the strange thing. There's no error entry. I've had leaks in the LD system before, and those always came with an error message like "Limit exceeded..."

Here, I can give it full throttle for 90 seconds, and the only thing I notice is that the load demand (LD) isn't being met, and there's noticeably less power. Otherwise, the usual result was limp mode and a lot of smoke.

@Clause.

Thank you for the explanation. Is it possible that the VTG (Variable Turbine Geometry) is stuck in a certain position, causing the LD (Lean Definition) to not be reached at low engine speeds due to the insufficient exhaust gas flow, and this issue continues as the engine speed increases?

Best regards,

Hello,

Even if you are not using my VCDS distribution and the log was unnecessarily messed up with semicolons, the amount of air mass that you see is far too large for the achieved boost pressure.

Remaining possible causes include:
- The LMM (mass airflow sensor) is showing excessively high readings, the vacuum hose to the turbocharger is torn/damaged, there's a problem with the VTG (variable turbine geometry), etc. -> It's unlikely that all of these issues are occurring simultaneously.
- Charge air is being lost before it reaches the engine. -> There's a leak in the charge air system. Is the pipe from the exhaust manifold to the EGR valve okay, and is the EGR valve itself working correctly?

Best regards, Rainer.

dieselschrauber wrote:

The intake air is being lost before reaching the engine. -> There is a leak in the charge air path.

That's also my suggestion, because the actual value of the mass airflow sensor (LuMa) is constantly at the maximum of the diagnostic scale (1250 mg/stroke), which is completely atypical for an ARL even with normal boost pressure, especially if it hasn't been chipped.
The emergency mode won't be activated here because the corresponding error threshold hasn't been reached yet. However, your charger could still fail at any time during one of the next full-power charging cycles.

Hello,

Thank you for your answers and tips, which I was already aware of from reading the forum.

@Dieselschrauber
I know that I didn't use your VCDS distribution. That was because I had the version from Ross Tech installed for the Crafter. However, the adapter is from you.

I've reviewed quite a few things today.
LD line retested. --> OK (I'm not surprised, everything is new).

VTG Leichtgängigkeit mittels Grundeinstellungsmodus im MWB 11 getestet. Dabei ist mir aufgefallen (Optisch) das sich das Gestänge sich sehr zögernd bewegt. Grand:

Exhaust gases are escaping from cylinder 4. Either there's a leak between the cylinder head and the exhaust manifold, or the exhaust manifold itself has a crack. There's a lot of soot visible, and it had clogged the VTG linkage. I cleaned it and lubricated it thoroughly. Then I ran the test again in the diagnostic tool (MWB 11). The linkage is now moving faster. Now I can understand where that slight ticking sound between 1500 and 2000 RPM comes from; it's probably the exhaust noise. However, it's very quiet.

I took it for a test drive, and the lambda value now goes up to just over 2600 mBar and settles quickly at around 2500 mBar. The pulse width is also now approximately 60%. However, the air mass remains at 1250 mg up to 3000 RPM; it only starts decreasing slowly after that.

Now, my question is:

Does anyone know if cracks in the exhaust manifold are more common or if the seals fail more often on TDI engines? The linkage is coming loose. The turbocharger was replaced at with 220,000 km. There have been no problems since then.

I will seal the issue soon, but I have other things to deal with at the moment. Tomorrow, I'll be driving another 450 km and I'll take the laptop along this time so I can observe what's happening.


Best regards,

charlyfirpo wrote:

Took it for a test drive, and the LD (lambda value) goes back up to just over 2600 mBar and adjusts quickly to around 2500 mBar. Also, the duty cycle is now approximately 60%.

However, the air mass remains at 1250 mg at 3000 RPM. Only then does it slowly decrease.}} Something still isn't right. Could the airflow around the MAF sensor (mass airflow sensor) have been altered somehow?

Quote:

Exhaust gases are leaking from cylinder 4.

Either there is a leak between the cylinder head and the exhaust manifold, or the exhaust manifold itself has a crack. [url]

[/url]/viewtopic.php?t=24589&highlight=exhaust+manifold+arl}

If it's just a little bit, it's not a big deal.

See Ulf's post.

no, I haven't changed anything.

I've logged a lot of data with my car before, but I never really paid attention to how high the values were when accelerating at full throttle.

I only performed a test drive with an optical check using VCDS after troubleshooting.

Since I'll be on the train again tomorrow, I'm going to log another entry while in 6th gear. Let's see what that results in.

RedR32 wrote:

Exhaust gases are leaking from cylinder 4. Quote: Either there is a leak between the cylinder head and the exhaust manifold, or the exhaust manifold itself has a crack. /viewtopic.php?t=24589&highlight=exhaust+manifold+arl If it's just a little bit, it's not a big deal. See Ulf's post.

Well, it's a bit more complicated for me. I tried taking pictures, but you can't really see anything in them. Unfortunately, I don't have a lift or pit, so I had to lie under the car. And because I only have an SLR camera, there isn't enough space.
I'll leave it as is for now and see what happens.

"Thank you for the link anyway."

Hello,

Here's the log from today. I think it looks pretty good.

I read Ulf's post. The idea of planning the exhaust manifold flanges is good. I just need to see if I can find a shop nearby that can do it. I don't have the means to do it myself.

Best regards,

Hello,
Okay, I could only read the data when it was compressed into an XLS file, which made it difficult.
Despite this, here are my questions:
Is it correct that the target value for air mass is 850 mg/stroke at the ARL?
The torque limit appears to be just below the smoke limit.
Both seem problematic to me.
haithamina

haithamina wrote:

Hello, Okay, so I could only read the data when it was compressed into an XLS file, which is difficult.

This can be fixed in Excel using "Data -> Text to Columns".

Quote:

Is it correct that the target value for air mass is 850 mg/stroke at ARL? The torque limit appears to be just below the smoke limit. Both of these seem problematic to me.

However, everything appears normal with the 019AQ. Even with perfectly intact hardware, the logs wouldn't look significantly different.

Here's the translation:

For the log: Now, suddenly, the actual luminance is in a plausible relationship to the actual light density.
In the first log: more boost pressure (LuMa) with less load demand (LD), which can't be right if the intercooler piping is too restrictive .

ulf wrote:

However, everything seems normal with the 019AQ. Even with perfectly intact hardware, the logs wouldn't look significantly different.

Okay, Ulf.
Yes, that's right. I was just looking at other ARL logs and noticed myself that the target values are so good. Well, then I'm finished.
haithamina