TDI Golf 3: Common Problems & Solutions

Hello everyone!

I'm having the following problem/issue.

Today, I had a chip installed in my Golf 3 TDI 110 hp (AFN) by a well-known brand tuner (********).
I'm also very satisfied, but I have the following problem.
I was on the highway earlier and wanted to see how it performs in terms of acceleration and pulling power.
Starting from the third gear, I began to accelerate, and it was quite noticeable that the engine was pulling strongly. However, between 2900 and 4000 RPM, there was suddenly a slight 'hiccup,' as if something was preventing me from accelerating further. Then it picked up again until I shifted into fourth gear. Right then, I experienced the same problem in fifth gear as well.
Okay, so to put it briefly: It starts accelerating really well, but then something slows it down.

Does anyone have any idea what this could be? I'm completely at a loss!
Okay, the mass airflow sensor is in excellent condition!

Please provide many suggestions to help me with my problem.

Thank you in advance!

P.S.: Could it possibly be the turbocharger? Is there perhaps a defect with it? Two weeks ago, when my car was on a lift, I noticed that the bottom of the turbocharger had some oil residue on it. Could this mean something?

Does it sound like turbo lag?

Yes, I've thought about that too. But that extreme?!?!?
Is that really happening? / Is that possible?
It suddenly drops very sharply. You can really feel how it goes from accelerating to zero acceleration almost instantly.

Hi,

How do you know that the mass airflow sensor is "TOP"?

If you can be certain of something and measure its values, then you already have all the technology and knowledge you need to solve your problem.

Carefully log the measured values from the engine control unit; the problem should become apparent then.

Otherwise, simply return the product to ******** and claim a refund for the chip.

Unfortunately, we can't provide much assistance online with the statement "er zeiht nicht."

Please search for "performance loss" and read the relevant technical articles.

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

Have you perhaps experienced something similar before, but in a milder form? This could indicate a sticking or malfunctioning VTG (Variable Transmission Gear), which is now becoming more noticeable.
Technical article.

Neno wrote:

but then, between 2900 and 4000 revolutions, there was suddenly a small "stop," as if someone were holding me back from accelerating further. Then it came again for a bit, until I shifted into fourth gear. Right there, I had the same problem as I did in fifth gear.

[Speculation ON]
******** limits the amount of fuel injected even under normal operating conditions (i.e., with a functioning mass airflow sensor and without extreme ambient temperatures, etc.) by adjusting the opacity, in order to convert every bit of air drawn in into power. As far as I know, this is common practice among chip tuners.

If he doesn't adjust the boost pressure control parameters to match the more powerful turbocharger system (which, as far as I know, only a few tuners do), the control can become inaccurate and constantly require readjustment during operation, meaning it will continuously correct the pressure downwards despite a higher target value set in the boost pressure map.
This directly affects the fuel injection amount and power output due to the constantly active soot reduction system, meaning you'll feel every change in lambda (air-fuel ratio) in your seat.
On an oscilloscope, you should be able to see the fluctuations -> overall, a second-rate chip...?
[Speculation OFF]

Hi!

@ampac!

Yes, that's exactly how it was and is for me.

Without the chip, I also noticed this slight twitch, and now with the chip, I notice it even more.
So, does it depend on the turbocharger or variable geometry turbine (VTG), or what?
What can be done about this? Any tips?

Best regards,

@ulf

The problem is exactly as I described above.
Even without the chip, I notice a slight twitching sensation, but with the chip installed, it's even more pronounced. So, I can't quite imagine that it depends on the Wetterau chip.
As I said, I believe the problem lies somewhere in the turbocharger.


Okay, one more thing! I just went to Volkswagen and had a brand new mass airflow sensor installed to see if the problem might be related to that.
No, quite the opposite! He's behaving exactly as before, just like with my air flow meter.
So, it must be something wrong with the turbo, right?

Taking a deep breath always helps me.

Find a lonely stretch of highway.
'Just give me some chewing gum for a few minutes.'

The problem occurs for me repeatedly, and I haven't been able to fix it despite trying various solutions.

Does it get worse for you in hot weather?

You could also get the large vacuum chamber from the Vnt17 turbocharger.
That's where the VTG control has more power.

Otherwise, you can find a detailed and illustrated guide on how to verschandeln your turbocharger in the specialized articles . Have fun!

You don't have an air volume meter.

This is an air MASS meter - that's the difference.

Check how your turbocharger boost pressure is regulated – at the very least, install a boost pressure gauge; even better, use a VAGCOM log to monitor it.

We can then interpret that for you.

The rampant exchange of parts primarily enriches Volkswagen dealerships.

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

Hello!

Thank you everyone for your helpful contributions!

@BesidesMommy

So, I have made your suggestion on several occasions , but as I said, without much success.

@dieselmartin

Excuse me! That's what I meant .
I didn't buy the LMM, but only borrowed it briefly, installed it, and took it for a test drive. I have some acquaintances at my VW dealer who can make something like that possible .

I will first have the support structure of the VTG and the vacuum sensor, as well as the entire vacuum system from Volkswagen, tested.
Maybe I can make some progress there.

See you soon.

Neno wrote:

Even without the chip, I notice a slight twitch, but with the chip, I feel it even more.

Hmm, that reminds me of the same puzzle I saw at my ex's place.
During the DZR test, if the typical LD over-boost reached up to approximately 1.2 bar at any point below 2000 rpm, this was also noticeable during acceleration: when the final adjustments were made, the engine (without any tuning!) then pulled slightly less strongly.

Since my good old Pierburg mass airflow sensor was always in top condition, the occurrence of high boost pressures during acceleration cannot be explained by active soot reduction, i.e., an extra dose of diesel during the overboost phase... but perhaps it's due to the higher air excess that would then increase the engine's efficiency compared to normal full-load operation?

This could also elegantly explain the summer sluggishness of VP-TDIs: high LLT (lambda) at the same LD (load) equals lower air density, which results in less excess air and therefore poorer acceleration – but all still within the engine speed limit, so without significant soot production.

Given that Neno's modified AFN (air-fuel ratio) likely operates with less excess air at full throttle compared to the stock configuration, fluctuations in lambda values could become more noticeable in acceleration – even without the soot reduction system being active under full load... ?

Can the trained motor specialists confirm these assumptions?