Golf 2.0 TDI 110hp - boost pressure too high at partial load

Hello everyone,

Here's a problem with a 2.0 TDI 110hp "Dieselgate" update:

During regeneration, the car enters a limp mode because the boost pressure becomes too high - under partial load (!). Interestingly, the log shows correct target values, but the actual boost pressure still increases, or rather, the ECU controls the wastegate in a way that causes the boost pressure to increase.

I'm looking forward to hearing your ideas...


Hello.

Hi,

Quote:

Interestingly, the log shows correct target values.

Well, I think that's perfectly normal, how else could it be?

The control unit specifies a target value and attempts to adjust the actual value so that the target value is achieved.
That won't work for you; I can immediately think of three possible reasons why.
- The VTG (Variable Turbine Geometry) adjustment on the turbocharger is stiff. Was a tuning box possibly installed in the past?
- Ventilation of the vacuum system is blocked (hose connecting to the upper part of the air filter housing).
- The magnetic valve (valve block) is connected to the turbocharger boost pressure control system.

See also:
I'm sorry, but I cannot access external websites or specific files online. Therefore, I am unable to translate the text from the provided URL.

Best regards, Rainer.

Please check the VTG position in the log starting at timestamp 140.
He is closing the VTG completely!

Unless the 0/100% setting was reversed during the "Dieselgate" update.
When I'm in third gear and flooring it, the target/actual value is working perfectly.


Does measurement block 11 actually show the real control signal, or is it showing the signal that the MSG (presumably a device or system) intended to send?

Hi,

Whether the "VTG close" command is at 0% or 100% varies depending on the engine control unit. It's best to check this using the actuator test function, which shows the duty cycle at which the boost pressure increases (VTG closes) or decreases (VTG opens).

If the VTG (Vehicle Tracking and Guidance system) is configured incorrectly, the described error message may be the result. However, in most cases, only inexperienced or unprofessional installers cause this issue and drive customers away.

Okay, so let's start by checking whether the VTG should be included or excluded.

Best regards, Rainer.

Just checked:
100% means VTG off, and 0% VTG on, as I intended.

The logic doesn't make sense to me at all. Unless the magnetic valve/vacuum system is completely malfunctioning, AND the measured position of the pressure sensor is indicated in the last column of module MWB11.

And the log is explicitly set to partial load; at full throttle, the control behavior is exemplary.

Hello.

Normally, with an EDC17 system, 100% corresponds to full vacuum pressure in the can, which is a maximum of LD (lambda), and 0% means no vacuum at all. And that seems to be what's happening with you; at timestamp 152, you have 95% activation, and the LD value is accordingly high.

What about the throttle valve and the EGR system during regeneration?

The image shows the control parameters for boost pressure and the PID parameter tables.

It's from a CBBB engine with 170 horsepower.

Based on the sensor data you provided, the VTG setting doesn't seem unreasonable, because up to a certain fuel injection quantity, it only operates based on the control map.
The question I have is: how can he achieve 0.8 bar of boost pressure with only 3-4 mg/H and 2000 rpm?

That would be great for an anti-lag system, but in this case, it's probably not what's intended...

Throttle and EGR during regeneration need to be checked. Then the problem must lie somewhere else.

Edit:
Problem seems to be found. Improper deactivation of the EGR system... If you don't do everything yourself!

Thank you.

Hi,

Quote:

Edit: Problem seems to be found. Improper EGR valve deactivation... If you don't do everything yourself!

I've just been racking my brains trying to figure out how this could be possible, so it was shoddy workmanship after all.

Best regards, Rainer.
Here's my two cents: If there's any tuning done, it seems pointless because the boost pressure is still stock, and at first glance, the fuel injection amounts look like they're way too high.
Caution: Turning off the AGR system is prohibited ^(TM) . Furthermore, if it's turned off completely, it's not really useful because the engine hardly warms up in cold weather, and DPF regeneration becomes unnecessarily difficult or impossible.

"@Blackfrosch, you mentioned in your first post that you have the NOx update installed. Has it been further optimized since then?"
How was the AGR deactivated?

@Rainer, I'm not sure if my reasoning is correct.
That's true that the engine hardly reaches its operating temperature in cold conditions, but with a lower or no EGR rate, there should also be less soot in the exhaust gases, or am I mistaken?

Quote:

@Rainer I don't know if my reasoning is correct. It is true that the engine hardly reaches its operating temperature in cold conditions, but with a lower or no EGR rate, there should also be less soot in the exhaust gases, or am I mistaken?

Yes, the engine's intake manifold will likely accumulate less sludge, but you'll experience longer cold start times and potentially encounter issues with regeneration if your personal driving profile isn't suitable.

Best regards, Rainer.

chli1976 wrote:

@Blackfrosch, you mentioned in your first post that you have the NOx update installed. Has it been further optimized since then? How was the AGR deactivated?

Based on what I can see from here, regarding the two incorrect H***** characteristic curves out of a total of six, starting at 1200 rpm. Apparently, the air mass control via the throttle was deactivated during regeneration (starting at 1200 rpm). According to the logs, the EGR system was permanently active in normal operation...

I know the software developer (a private individual) and therefore initially didn't think it had anything to do with the AGR deactivation. That's why I didn't mention it, because the error log appeared in the "standard performance range." Sorry for any confusion on that matter.

Regarding the issue of the engine not warming up:
The minimum regeneration temperature for this vehicle is 61°C coolant. The vehicle is driven at a brisk pace in the foothills of the mountains. It's a Variant with a DSG transmission - it easily reaches 60°C. The amount of soot entering the filter decreases significantly. Furthermore, the EGR system has a better chance of lasting 200,000 km. Normally, you should expect to replace the EGR cooler module or the EGR valve around 80,000-120,000 km for approximately €600.But I don't want to sugarcoat things; the shutdown is illegal and it doesn't only have advantages.

The EDC17CP14 is generally not as problematic as the EDC17C46.
My friend has been driving for over 3 years and 60,000 km with the EGR system deactivated.

"Back then, I used all four Hy*** tools on our cases and it worked. Nowadays, I do things differently. First, I did an EDC17C46, and immediately tried a service regeneration, which was successful. After a week, I checked again to see if it had regenerated, and it had."

I've also had some that worked perfectly for a year and then suddenly stopped regenerating, even with the EGR system turned off.

I think this is getting too off-topic... The problem in this thread has already been solved. We shouldn't really be providing instructions for disabling the EGR system here.