TDI Beetle Won't Accelerate: Brake Issue at 2500 RPM

Hello!
My sister has a 90hp TDI Beetle and is complaining that the engine feels restricted from around 2500 RPM, as if the handbrake is engaged. From about 3000 RPM onwards, it then runs 'normally' again. This is especially noticeable in the higher gears, as you quickly pass through this restricted area in first and second gear. Interestingly, this behavior occurs consistently, whether the engine is cold or warm. Otherwise, it runs completely normally; there's no jerking, smoking, or anything like that. It just lacks power in the aforementioned RPM range.

What could it be? A mass airflow sensor (MAF)? A turbocharger? The 90hp TDI engine doesn't have a variable geometry turbo (VGT), does it? It's a Beetle from the year 1999.

Sure, here's the translation:

'Thank you for your help.'

Greetings.

Yes, the 66kW Beetle (the engine code should be ALH) has a variable geometry turbocharger (VTG).


Best regards,
Rudi

Hi there,

First, I would connect my sister's TDI to a laptop using VAG-COM and run a diagnostic scan.

Then you almost know everything - and what you can't figure out, we will .

It's possible that the issue is occurring precisely in the area where the boost pressure is regulated at 2500, and that something is sticking or malfunctioning there.

Is she flighty?

You can tell whether a vehicle is VTG or not by looking at it (or by reading the engine identification letter).

Okay, please provide the German text you would like me to translate into English. I will only provide the translation.

Hello everyone!
What I would do is clear. But the Beetle is 140 km away from me, and I think my sister probably can't even find the hood release .
I can't look anything up. She will almost certainly be seen by the doctor soon. It probably won't work any other way. A visit should clear everything up, because he does it regularly anyway.

Does the 90hp TDI engine in the Beetle really have a VTG (Variable Turbine Geometry)? So, it could actually be that technology! Well, I know there's still warranty on that .
Is it true that if the linkage gets stuck, you'll never be able to fix it properly so that it stays in place permanently? My 'master' once told me: 'If the VTG (Variable Transmission Geometry) is stuck --> replace the entire loader.'

Greetings.

I would probably emigrate to Mars if there were a fixed VTG .
If the VTG is fixed, there's no point in using Laben anymore.

I've never heard that you can't get those back in common use again.
VW will simply never start cleaning up its act, because they can't offer a guarantee for that.

Are 140 km too much for your little sister??? My sister is doing well!!!

Only the first 90 horsepower version of the G4 had a wastegate (engine code AGR); later, the ALH engine with variable turbine geometry (VTG) was introduced.

If it's still under warranty, contact Volkswagen!

Okay, please provide the German text you would like me to translate into English. I will only provide the translation.

Hello!
But wait . Maybe there was a misunderstanding. My supervisor didn't say that they couldn't do it normally; he said that they have done it many times before, but now they refuse because it's not sustainable. Apparently, you can't verschandeln it in a way that makes it last. And to avoid the hassle with customers, they simply don't do it anymore. That's why the statement: 'VTG is stuck ---> new loader.'
Wenn es wirklich der Lader (VTG) ist und ich das selbst bezahlen müßte würde ich ihn auch selbst reinigen, wenn ich mal sehen würde wie man das macht Hat das mal schon wer hier gemacht? GibSure, here is the translation of the text from German to English:

'Are there any pictures available?'

It's clear what you mean by 'making a fuss with VW.' Unfortunately, the dealer where the car was purchased is very far away. If it's something like the mass airflow sensor (MAF), for example, the trip simply isn't worth it. That's what it's about. But as I said: she should go to a nearby and have a diagnosis done. Then you can decide whether or not to make the long journey. Definitely check the turbocharger .

Thank you all!

Greetings.

96kwtdi wrote:

It's clear that "making a fuss with VW" is the approach. Unfortunately, the dealer where the car was purchased is very far away. For example, if it's the mass airflow sensor (MAF), the trip there simply isn't worth it.

You can also have it done by the local public transportation company (VAG), and they will then bill the dealer for the work. I've had a starter replaced that way before.

Images from VTG:

http://www.technologie-entwicklung.de/Gasturbinen/VNT15-Turbo/vnt15-turbo.html

Danke für den Link! Great website!
Here's the translation:

'One more question: how can you test its ease of movement? Disconnect the vacuum hose from the VTG unit, and then the rod should move easily. But how easy is 'easy'?'

Ist das eigentlich kein Problem wenn man die Schrauben des Turbos löst und dann wieder wieder verschraubt? Müssen die nicht auch mit dem richtigen Drehmoment angeschraubt werden? GDoes it have any specifications?

Thank you all.

Greetings.

Hello.

It won't become any easier to operate if you disconnect the hose, because the cylinder has a return spring. Simply try to move the rod against the force of the spring. It shouldn't catch or have noticeable resistance within its adjustment range.

But that and much more is actually explained here https://community.dieselschrauber.org/en/viewtopic.php?t=2992.

Hi, it's me again!
I was able to 'test drive' the Beetle over the weekend. But, as luck would have it, for some reason, it didn't work at that time.
If this is the issue, then I may have felt a very slight and brief 'hesitation' just before reaching 3000 RPM once or twice. But I don't know the engine *that* well. It could also be normal.
The existing strut, if present, is difficult to test on the Beetle because it's hard to reach . Perhaps it's actually the mass airflow sensor (MAF) .

'What I've noticed, and what the Beetle *always* does, is something that I find very annoying and, in my opinion, not normal: The engine starts with great reluctance. You have to crank it for a long time before it finally catches and comes up to idle. You definitely have to hold the key in the start position for at least 4 seconds until it revs up. Then it runs normally. However, I don't think this starting behavior is normal, especially since we also have an AFN model in the family that starts *immediately* when you turn the key to the start position.'
The engine code is ALH.

I am grateful for any advice.

Greetings.

"My car also had similar starting problems, but only when the engine was warm. I cleaned and re-lubricated the starter motor. However, this didn't work for my engine. Then a new starter motor was installed, and since then, the engine has started perfectly even when warm. The old starter motor wasn't reaching the required speed. You can find many posts on this topic here."

Hello!
Ja warm ist es noch etwas schlimmer, aber auch kalt dauert das viel zu lange. Aber rein vom Gefühl her dreht er sich schnell genug. Kann aber auch täuschen. Die Beiträge dazu muß ich gleich mal suchen. Betrifft das nur den ALH? Was How much does it cost?

Greetings.

I couldn't hear if the starter motor was missing any rotations. Actually, the old starter motor sounded quite good. Supposedly, the new starter motor should provide a slightly higher RPM than the old one. The starter motor cost about 270 euros at the dealership, but I'll check the invoice again tonight. Maybe you should have the starter speed measured. Then you'll know for sure.
And first, check all the other possible causes.

Hello!
Regarding the warm start problem:
'A workshop foreman mentioned yesterday that the problem is likely due to the timing belt being set at its 'limit'. I wasn't there when he said it, but he was talking about a 'lower limit of 30', and my sister's ALH engine has 32. So, it's technically still within specification, but that can already lead to starting problems when the engine is warm. If adjusting it doesn't help – which he doesn't recommend because it's too expensive – then the problem might actually be with the starter motor. I'm not sure what he meant by '30'. It could possibly refer to something like the fuel injection timing, or something similar.'

Yesterday, the Beetle was brought in for a diagnosis. The Mass Air Flow sensor (MAF) was the main problem, but there's also a second issue. Apparently, there's overboost, and according to the mechanic, this is due to the difficult-to-move VTG adjustment mechanism. The turbocharger control valve or sensor is supposedly okay. Currently, the VTG is still working, but it could completely fail in 3 weeks or even 3 years, causing the ALH engine to go into 'limp mode.' Those were his words .

Can anyone comment on this and confirm it? What would be the best next step? Should I replace the charger myself? Shouldn't that be straightforward? Does it need to be calibrated or adjusted via diagnostics? Where can I find affordable replacement chargers with a warranty?

Sure, here's the translation:

'Thank you for your help.'

Greetings.

Oh my goodness... well, I'd rather adjust the fuel injection timing than replace the starter motor.
But the starter motor is much more expensive -> profit margin .

Best regards, Rainer.