AJM Turbo: No Boost Pressure?

Hello everyone!!!

Today, I'm writing in again, and this time with a problem.
I bought a used AJM Golf 4 with a 6-speed transmission two weeks ago.
(My Eclipse will remain in the garage until the initial issues and problems are resolved.)
During the test drives, everything was working perfectly, and because I have a diagnostic tool, there were no error codes stored until today.
I'm about to go on a test drive using VCDS. When I got back, there was an error code in the diagnostic memory:

Turbocharger pressure control - Regulation limit exceeded!

Is that the boost pressure control valve, or could the mass airflow sensor (MAF) be faulty? I couldn't find a definitive answer in the technical articles.

Due to LMM (likely referring to a Low Mass Measurement), I found the values to be quite low, for example: RPM: 3003, Load: 100%.
LMM: 338.1

Unfortunately, I don't yet know how to post the 2 LOGs.

I would be very grateful if someone could help me.
Oh, so yesterday I lost a screw in my ?GR. Any consequences?


The car has 113,000 km on the odometer and is a 2001 model.

Check the vacuum supply; the thin hose near the brake booster often chafes.

Thank you for the quick first aid. I will definitely try that.
It can't be happening that I'm now experiencing the typical problems that are common with TDI engines.
Couldn't he have at least waited another 2 or 3 weeks?

Thank you, roli752001!

Okay, I now have a log of the test drive.


UPM Absolutdruck Absolutdruck Tastverhältnis Luftmasse/Hub Absolutdruck Absolutdruck Last UPM Einspritzmenge Kraftstoffverbr. Injection amount.
TIME TIME
/min mbar mbar % STAMP mg/R mbar mbar % STAMP /min mg/R l/h mg/R
903 1010 979 19.9 0.77 254.8 989 979 0 1.17 903 4.9 0.6 0
903 1010 989 19.9 1.97 254.8 989 979 0 2.38 903 4.9 0.6 0
903 1010 989 19.9 3.19 249.9 989 979 0 3.59 1134 11.3 1.8 10.4
1155 1183 989 20.3 4.41 240.1 989 989 34.5 4.81 882 20 2.4 53.3
1155 1612 1000 19.9 5.61 230.3 989 1000 100 6.01 1533 17.6 3.8 59.8
1743 2091 1020 24.7 6.82 245 989 1061 100 7.22 2184 17.8 5.6 56.5
2394 2091 1173 25.1 8.01 259.7 989 1244 0 8.41 2037 0 0 0
1638 1326 1132 36.3 9.21 249.9 989 1102 43.1 9.61 1596 17.6 4 59.8
1659 2040 1102 24.7 10.41 264.6 989 1122 100 10.81 1827 17.8 4.6 59.3
1911 2091 1153 24.7 11.63 284.2 989 1183 100 12.03 2079 17.8 5.2 57.4
2163 2091 1244 24.7 12.83 298.9 989 1285 100 13.23 2352 18.1 6 55.2
2436 2091 1367 25.5 14.03 313.6 989 1418 21.6 14.43 2184 0 0 0
1617 1112 1173 39.8 15.23 284.2 989 1163 100 15.63 1659 17.8 4.2 59.8
1701 2071 1153 24.7 16.45 294 989 1163 100 16.85 1785 17.8 4.6 59.6
1827 2091 1183 24.7 17.65 303.8 989 1193 100 18.05 1890 18.4 5 58.7
H.

Hi!
First, a question:
Why is it that the excellent converter that comes with VAG-Com is almost never used? With it, you can convert those impractical .csv files into great .xls files! Then you wouldn't have to struggle so much with the endless numbers... Also, you can easily create graphs and actually do something with them.

Since your log is relatively short, I took a quick look at it and created a diagram.



I think it's great to see that almost nothing is happening with your boost pressure control valve (the duty cycle hardly changes), and that's why a proper boost pressure can't be built up.
Okay, check the valve, the control system, and the VTG adjustment!

Sure, here is the translation of the text from German to English:

"MFG" is an abbreviation for "mit freundlichen Grüßen," which means "best regards" or "sincerely." It is commonly used in German-language emails and letters.

Hello and thank you wbuchi82!

Okay, then I'll start looking into the topic of matter conversion.
It's nice of you to put that into a meaningful diagram in such a short time.

Can someone tell me where I can find the boost control valve on the AJM PD engine?

What other aspects of an LMM (Large Language Model) age or degrade over time?
The car was purchased from a private individual. A woman drove it over a long distance. She wasn't sure if the mass airflow sensor (MAF) had ever been replaced, as the car had always been serviced at a VW dealership.
Suggestion for VW: Include a field in the system for recording the date and mileage when a Mass Air Flow (MAF) sensor is replaced.

Sure, here is the translation of the text from German to English:

'MFG' is an abbreviation for 'mit freundlichen Grüßen,' which means 'best regards' or 'sincerely.' It is commonly used in German-language emails and letters.

Hi!
It's definitely not the turbocharger causing the lack of boost pressure you're experiencing. I would only re-check its condition after the pressure problem has been resolved using VAG-Com. However, if it hasn't been replaced yet at 113,000 km, I wouldn't be surprised if it's starting to show its age...
You can find your target data here... http://www.dieselschrauber.de/Solldaten_4_Zylinder_PD.html

Unfortunately, I don't know the exact location of your boost pressure limiting valve. I'm not very familiar with the AJM engine. However, the easiest way to find it is to follow the thin control hoses from the turbocharger (vacuum actuator) to the valve in question.

Sure, here is the translation of the text from German to English:

"MFG" is an abbreviation for "mit freundlichen Grüßen," which means "best regards" or "sincerely." It is commonly used in German-language emails and letters.

On the injection wall, driver's side. The 'module' containing the AGR/LDR valves...

Okay, I've now (thanks to Diesel_Rudi!) carefully checked the control lines.
However, I didn't find any loose connections or friction points.
So, I was thinking about the well-known principle: Never touch a running system!
A blockage in the **R** was cleared.
And then, suddenly, it pushed me back into the seat.
What kind of connections are these again?
It's a shame, because I also wanted to prevent the sludge from entering the intake area in the future.

After another test drive, the values are plausible and there are no error entries.

Despite everything, thank you to those who helped.

That's strange, because your LLM values are higher with a functioning EGR system than with a defective one.

Take that thing apart, it seems like something is stuck in the mechanism. Clean it thoroughly, and then hopefully the problems will disappear.

Normally, the valve doesn't open when the hose is disconnected.

Hi, it's me again!
How did you actually disable the EGR? Since the boost pressure was missing in your log, it must have been leaking through the EGR. It's likely that the mechanism is already so worn that the EGR doesn't close properly (or not always), allowing the boost pressure to escape into the exhaust. Your low lambda values, despite the disabled EGR, also suggest this.
Actually, there's only one solution here, because this error is sure to happen again.
"Get rid of the junk and thoroughly clean it in the parts washer - make the mechanics move freely again - run some logs with the EGR active - then temporarily disable it using a metal plate (but make sure it's a tight fit) and go for another test drive..."

Here's what happened in my case:

Clogging on the vacuum sensor hose.
I'm planning to clean the AGR unit next weekend.
While inspecting the system with the thick hose disconnected, I noticed a black, paste-like substance. That's why I made the decision I did.
I'm probably starting this action thousands of kilometers too late.
Could that also be a reason for the high fuel consumption?
Today, after the first 90 kilometers, I refueled and managed to put in 8 liters.
Okay, there were a couple of short trips, but always with the engine warmed up.

Thank you for the great pictures.

Hello!

I couldn't wait until the weekend, so I already gave AGR a bath yesterday and today.
Just wanted to mention that I allowed the coolant to enter the system. The AGR (Abgasrückführung - exhaust gas recirculation) valve was probably stuck after about 100,000 km and was likely only closing 'sporadically.'
Now everything is back to normal. Thanks also to wbuchi82 for the idea.
It accelerates quite well, reaching around 200 km/h on a straight road. I'm hoping that the 10-cent modification (which is currently being worked on) will increase the speed towards 220 km/h. Then I will have reached the top speed of my Mitsu with the legendary 4G63 engine (which is something like the 1Z engine from VW, but it's a gasoline engine). It now has 263,000 km on the clock with the original clutch and a fuel consumption of 8.5 liters, almost no oil consumption, and the original exhaust system!
Although this isn't primarily important, one doesn't want to be too... (The sentence is incomplete, so the translation ends here.)
Degrade the car beforehand.

'With the pump-injector system, a change of just 10 cents likely involves tuning the diesel temperature sensor, and that definitely wouldn't achieve a speed increase from 200 km/h to 220 km/h.'

Even with other tuning modifications for the TDI, you might only see an average of 5 km/h more.

If you want more speed, you either have to buy a different car or modify the gear ratios.