AJM power loss, not turbo pressure

Hello, I've been having a problem with our 4 Golf 2001 AJM 115HP for about half a year. It has 310,000 km on the odometer.
I replaced the head gasket in the winter because it was leaking coolant.
The head was disassembled and "partially overhauled" by a friend during his night shift. A pressure test was lightly applied to check for cracks and to remove minor indentations in the sealing area (it wasn't a big deal).

The PD elements were resealed and fitted with new adjustment screws. (The lowest point was reached using a dial gauge, then rotated 180 degrees and locked in place).

After assembly with the calibration tool, an extreme loss of performance and poor starting behavior were observed.

Okay, so initially, nothing worked, and I discovered that the VTG adjuster, which was needed for the head, had become stuck and corroded during the 3 months it was stored . I then freed it (it was incredibly stuck; nothing worked with wire) by hammering it out with a hammer and a broom handle... which worked well. Afterwards, the VTG adjuster worked properly again, smoothly and without any sticking (tested with a syringe and a vacuum pump).

There is no power output until 2000 RPM, and the maximum output is only 160-170, so there's no power gain at the top end either.

Okay, so I logged the boost pressure, and it's not reaching the full boost pressure, neither at idle nor in the lower RPM range, according to the various log files... and then you thought, "Maybe you messed up the basic settings of the variable turbine geometry (VTG)."
After trying various adjustments to the boost control system (replacing vacuum hoses, swapping the EGR solenoid valve, checking vacuum at the tandem pump and control valve, and blocking the EGR valve), I simply installed a used turbocharger for 50 euros (please no comments). Before that, I tried adjusting the linkage on the old turbo, but nothing changed except that the overboost pressure went towards 2.4 bar, while there was virtually no boost at low RPM.
Und siehe da der "NEUE GEBR" liefert haargenau die gleichen Ladedruckwerte wie der Alte und die Kiste läuft auch genau wie vorher.

So, I searched for it again, eventually gave up, and left the box untouched for 2 months.

I'm a certified automotive mechanic, but I don't have any experience with diesel engines. However, I've definitely disassembled and reassembled over 100 ZX9R, R1200 GS, and similar motorcycle engines.
But the diesel engine is driving me crazy...
Since I know enough automotive master technicians: Please check the intercooler system for leaks and verify the boost pressure.
He was, of course, relatively enthusiastic at first. Then, after about 4 weeks, he told me that he thought the "Turbo" version was terrible (which is ironic, because I already felt that way 2 months prior).

"Given that he has quite a bit of experience, I tend to believe him. What I find strange, however, is that before being disassembled, the car was consistently exceeding 200 km/h on the highway and accelerating like a rocket from a standstill. Why would two different turbos have the "same" defect? There's absolutely no difference! The VTG adjuster is free! I've also temporarily removed the exhaust, but the catalytic converter is still in place."
Okay, before I install a new Garrett turbocharger, which will cost around €500 (I don't want to hear anything about refurbished ones, there aren't that many "generals" driving around in Germany), I want to know if I might have made a major mistake during the assembly and adjustment of the PDEs. And is it possible that the turbine isn't getting enough power due to insufficient fuel injection?
The adjustment screws on the PDEs were definitely different!!
The old screws had a concave protrusion where the valve lifter sat. The new ones had a convex plate with a half-round shape that fit onto the half-round shape of the valve lifter. I didn't think anything of it; they were a Reinz set, including the O-rings and valve lifters!

Okay, I have absolutely no experience with PD injection values, but the MWBs (presumably engine control module data) that I've looked at seem to show good readings for idle control, injection quantities, etc. The synchronization angle also seems correct. I'm attaching the log files from back then, which show the mass airflow sensor (MAF) and boost pressure readings.

Perhaps someone could also tell me that I broke the PDEs with the other settings?

Hello,

solche Logs sind nutzlos. Please provide the text you would like me to translate from German to English.
Okay, I'm ready. Please provide the German text you want me to translate.

"An idle injection amount of 6.9mg/H would be acceptable for a cold engine. Please also provide the values for the idle speed control and an engine scan."

Best regards, Rainer.

Let's check the vacuum line for leaks; I usually do this with a hand vacuum pump.

Is the brake booster working properly? Also, is the line from the tandem pump to the brake booster in good condition, as it can sometimes rupture.

I once bought a Golf IV Variant with a 131 hp TDI engine that had the same symptoms, supposedly with a broken turbocharger. The actual cause was a crack in the aforementioned hose.

The vacuum line is sealed; I've attached a clock to it...
"I remember the values being 0.9 bar, and 0.6 bar after the solenoid valve (N75). I've already checked everything possible with the vacuum pump."

I'm having a problem with the Autoscan feature...
Since I've been using such an old version that I got from a friend and didn't purchase from you, I suspect the support might not be very good.

Since I bought an Octavia 5E, manufactured in 2016, last week.
I probably need a new VCDS anyway...

Does the VCDS diagnostic system HEX-V2 work with the VRS?
What's the difference compared to a workshop kit? I only use this stuff for private purposes!!!! Sorry, I didn't see the fin restriction in time.
Do you accept a used GS 911 pro yellow, older version without VIN restriction, as a trade-in?

Okay, I've finished my homework for now...
1.) I bought a VCDS from you (I think it will arrive in about 4 weeks).
2.) Turbocharger pressure control checked...
With the pressure gauge at idle, the available vacuum is 0.8 bar.
"After N75, 0.7 bar at idle."
At 1500 RPM, the value is 0.6 bar. When fully loaded, it goes towards 0.7 bar. And with increasing RPM, starting from 2000 RPM, it decreases to 0.4-0.5 bar.
3000-4000 RPM, 0.3 bar. Even when I fully opened it, the pressure gauge never dropped below 0.3 bar.
The tandem pump produces almost no pulsations during operation.
If I really push it to the maximum, the pressure will drop to around 0.84 bar. In that case, a maximum vacuum system and a tandem pump can be completely ruled out.
3.) The exhaust path has been checked, so when you put it under full load, a significant amount of exhaust gas will come out the back.
"However, I hardly notice any pulsations at idle or in the lower RPM range. So, I disconnected the hose at the front of the turbo and went back on the highway, and it performs even worse. The maximum speed is now 150-160 km/h (before, it was at least 170 km/h). The pressure difference during the turbo test is lower, about 30 mbar less. With a fixed boost pressure, it only achieves 120-130 mbar."
Knocked on the exhaust, no rattles. Took an endoscope from work and tried to see the catalytic converter...
I noticed that the flexible pipe is almost completely broken.
Could it be that the leak in the flexible pipe is affecting the pressure buildup to such an extent?

The flexible pipe was patched, and that fixed the problem.

Okay, I just created an Autoscan using my VCDS-Lite.

and I have reviewed all the measurement data blocks again for any irregularities.

Air mass charge pressure matches, or they are the same.
not enough...

"The actual fuel injection quantity was very negatively noticeable in test run 15."
"does not fit in any way with the requested..."
It's currently dropping by about half in the lower RPM range where there's no output, and it's also missing about 5-7 mg/stroke at higher RPMs.

Please upload the Autoscan and log files now. If I don't receive support, I'll have to wait until your VCDS is available.

Hello,

There are many posts and solutions related to your problem. Simply search and pay attention to similar posts at the bottom of each topic.

First, I would perform the basic settings in the engine control unit, specifically for idle speed, using measurement block 10 or 11 (you can determine which one is correct yourself).

The VTG (Variable Turbine Geometry) vanes are constantly opening and closing completely, and then closing again, every few seconds. First, we need to check what the adjustment lever on the turbocharger is doing; the expected range of movement is about 1 cm. It would also be interesting to see the actual boost pressure and the ambient pressure being measured by the engine control unit (measurement block 10).

Best regards, Rainer.

I'm already done with that.

Default setting mwb 11.

Pressure: 1070mb, release: 950-940mb, difference: 130mb.
and should be okay...
Both chargers operated smoothly and without any noticeable jerks.
1cm (only after disassembly and cleaning of the vintage item).

The old loader only managed to transfer 70-80 MB.
"The battery swap felt like it didn't do anything at all!!!"

I've already read through the entire forum.

Based on the vacuum readings, I would say that the engine control unit is activating the turbocharger quite aggressively, which is why...
I was planning to fix the 5cm crack in the flex pipe myself, but it turned out to be a bad idea.

I suspect that the turbocharger pressure problem is secondary, and that the turbocharger simply isn't getting enough drive.

Is it normal for the target injection quantity in the MWB 15 to vary so much?

I also tested the EGR valve. The LM reading is 470 when EGR is off, and 200 when EGR is on (the target value is 220).

PS: Another thing that completely argues against using a turbo is that, six months ago, I clipped the VGT (Variable Geometry Turbo) adjustment in place at the closed position and very carefully drove it up to around 2200 RPM... In my opinion, it didn't produce any power or boost.

Hi,

MWB 15 means nothing to me, and it's likely irrelevant. The quantity limits are specified in MWB 8.

Quote:

Ich vermute das das Ladedruckproblem sekundär ist und der Lader einfach nicht genug ANtrieb kriegt ?

"Good observation. Does the engine receive enough fuel? Is the diesel filter clear? Does the tandem pump build up enough pressure?"

Best regards, Rainer.

I didn't have time.

Here's the car scan. I'll also do a single measurement of MWB 11. What else would be helpful?

@ question
The diesel filter has been replaced.
The tandem pump builds up pressure gradually, reaching approximately 8-9 bar.
where the pointer is already wobbling violently...
(at the test connection for the tandem pump)

Okay, I also considered using a tandem pump before, but I dismissed the idea because of the fuel pressure issue.
What would it look like if there was air in the system?
What's frustrating me is that, aside from the lack of power, it runs very smoothly. There's no hesitation, no jerking, it drives like an SDI! And it starts up well too!
Okay, I'm going to check the compression again. It's possible they sent me a faulty head gasket... Even though the number of holes was the same, maybe the person who packed it accidentally punched too many or too few holes.

Klingt vielleicht banal, aber hast du evtl. einen Lappen in der Ladeluftstrecke vergessen? Das passiert ja relativ schnell. Möglicherweise ist er in den Ladeluftkühler gefallen und setzt diesen jetzt zu. Sind die Steuerzeiten korrekt eingestellt? Sind alle Unterdruckschläuche richtig angeschlossen und nicht irgendwo vertauscht? Ich habe schon gesehen, dass sich solche Schläuche beim Beaufschlagen mit Unterdruck selbst verschließen, indem sie sich zusammenziehen. Du schreibst du hast die Schläuche erneuert. DiThey must also be explicitly approved for use as vacuum hoses.

Of course, a happy new year to everyone in the forum!

I completely disassembled the charging cable assembly about six months ago because I had a similar idea before.
The Vtg is driven with a relatively sharp signal, as described above, which also...
"When the loader arrives, the connection to control the loader has failed twice; it's no longer working!"

I logged mwb 8, but I'm not really sure how to interpret the data. I don't have any experience with that, so I should probably just stick with my GS and R1s.
I would be very grateful if someone could take a look at this.

Hi,
The engine is running at approximately 2000 rpm in torque-limiting mode, not at the smoke limit. So, it has plenty of air at that point. Below that speed, the turbocharger seems to be spooling up slowly, and the variable geometry turbocharger (VTG) adjustment is likely not optimal.
I don't see any significant cause for a noticeable drop in performance here.
hg
Herbert.

VTG or Lader can be completely excluded.
After a diagnosis from 2 more certified automotive mechanics, who all...
Meinung waren VTG bzw Lader den Lader gegen einen AT-Garett von Motair getauscht den gabs für die alte möre beim Großhändler für knappe 380 inkl....
3 different chargers, all the same!
I've tried adjusting the basic settings (using the first turbocharger), but when I increase the sharpness, the boost pressure goes above 2.5 bar. It performs better at the top end with that setting, but probably not for long.