Performance Issues: Troubleshooting & Solutions

Good evening.

'For some time now, my TDI has been lacking that nice surge of power it used to have above 2000 RPM.'
I thought it was due to my alloy rims until last weekend. But now that I'm using steel rims, the problem is still the same.

On the highway, I'm only managing about 170 km/h .

I then replaced the mass airflow sensor (MAF) from a G3 TDI, the boost pressure control valve, and the pressure transducer. I also replaced some of the vacuum hoses. However, none of that worked.
At VW, they re-measured my mass airflow sensor during a test drive, but it's definitely working correctly.

Oh yeah, the fuel and air filters are also new.

My friend mentioned that he might just be getting frustrated because he's shifting gears too early.
Could that be the reason? I actually drive 30 kilometers of country roads every day, so it's not exactly short distances.
What's the best way to free him? Should I use diesel additives, or would you advise against it?

If anyone has another idea, I would be very grateful .

panther

Hey panther (are you the one from the Volksfest?).

What is the engine control unit saying?
Did it store any error codes?

How?? Don't you know?? Then ask someone!

I consider wild trading or adding extra ingredients without proper analysis to be a game for the rich!

Here in the forum, there's a wonderful guide for troubleshooting performance issues.
Please find it by searching!

I would do some research first before making any rash decisions.

What kind of results does he achieve in the pull test? Personal impressions can sometimes be very misleading (although a maximum speed of 170 km/h is already quite telling!).

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

Hi there.
Okay, I also occasionally visit the 'Volkstreff' forum, but mostly I'm on 35i.net.

'I also had the error codes read, but there were none. I took those parts off from a friend's car, so I haven't bought anything expensive yet, just the vacuum hoses.'

I'm going to check my EGR valve now and see if it's still working properly.

panther

Does anyone know the recommended values for the mass flow meter (LMM)?

At the Volkswagen workshop where they measured it, they couldn't find any specified values.
847 (?) was the value that it displayed. However, according to VW, it should be fine.

panther

[Translating...]

http://www.dieselschrauber.de/Solldaten_4_Zylinder_VE.html

847 is the maximum value that an older Pierburg mass airflow sensor CAN output.

When running at full throttle, that's the target value, but in reality, it's usually lower.

http://www.luxus-wg.de/~martin/auto_bilder/LMM_soll_ist_ueber_Zeit.gif

Whether that is relevant will be indicated by the block showing the fuel injection amounts.

As you can see, when it comes to a TDI, you can't avoid having an interface for reading out data. (After all, a computer without a monitor and keyboard isn't really usable either ).

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

'Like I do now, I've logged some data using VAG-Com.'

And thanks to Christoph and Peter, I can now also read the logs.
However, I'm still not quite able to make sense of the logs.
The turbocharger pressure seems to be fine. I will also install a new thermostat this week.
Otherwise, as I said, someone with more expertise would need to take a look at the file .

http://home.arcor.de/planetpanther/diagnose/panther-ladedruck.xls

panther

Hi,

Create a log entry with the identifiers 003-008-011 to capture all instances of performance bottlenecks at once.

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

Okay, my VAG-Com is working now, and I've just run a diagnostic scan with code 003-008-011.
http://home.arcor.de/planetpanther/diagnose/log-01-003-008-011.xls

Furthermore, I logged my speed on the highway, which was 170 km/h .
http://home.arcor.de/planetpanther/diagnose/log-01-006-007-015.xls

I hope you can find this useful.

'With the MWB 003, the MAF sensor seems to be malfunctioning above 3000 RPM. I don't think that's normal, right?'

is that normal for the values to fluctuate so much in this log according to MWB 4, or is it load-dependent?

panther

Evening.

I'm still no closer to solving my problem; I've measured and tested everything possible.

RPM Target mass flow rate Actual mass flow rate
1323 269.3 482.1
1344 295.9 488.8
1365 591.9 492.1
1722 847.9 724.9
2205 847.9 847.9
2646 847.9 847.9
3066 847.9 814.6
3465 847.9 668.3
3780 847.9 728.2
4095 847.9 675

What are the values like for a new LMM (Linear Mixed Model)? Are they the same as the expected values?
It's probably not possible to test a new mass airflow sensor (MAF) at Volkswagen, and if it's faulty, you likely can't return it.

panther

No.

Normally, electrical components are not returnable once they leave the store (and at our store, they are explicitly excluded from returns).

But if you suspect the LMM (lambda oxygen sensor), try replacing it with a new one.

http://www.luxus-wg.de/~martin/auto_bilder/LMM/Version_0.1.jpg

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

Yes, I had already looked into the issue with the diode, but I read something that suggests it only applies to a specific speed range.
I'll review the technical article more carefully.

What are your LMM values like? Do they deviate significantly from the expected range, or are your actual values close to the target values?

panther

Okay, something new again. I installed a new mass airflow sensor (MAF). The values were still high when the engine was idling. Could it be related to the faulty EGR valve?

U/min: Setpoint mass flow rate.
LMM: Actual mass flow rate.
882 252.7 485.5

'At TDI Timing, there's an injection start control setting labeled 'Ok' (or something similar), but it then indicates 'late'.'
Does it still have anything to say?
The brakes are not sticking, the turbo boost is correct, the intake manifold is clean, and the fuel and air filters are 15,000 km old.

I still remember exactly how surprised I was by how nimble such a 'large' car felt when I drove it for the first time. It doesn't have that nimbleness anymore.
edit: He no longer experiences this 'pushing' sensation at around 2000 RPM either.

The dwell time in the DZR is 9.58 seconds. Are there any comparable values available? I haven't found anything on the forum for a 35i.

Does anyone have any other ideas on what I could try? I'm starting to feel stuck. In particular, the mass airflow sensor (MAF) values are puzzling me.

I am grateful for any help.

panther

edit²:The LMM target value was incorrect... now everything is correct.

If the EGR valve is defective, the mass airflow sensor (MAF) values will consistently be too high, both at idle and possibly also under partial load.