VW Polo 1.6 TDI DSG: Power Loss Troubleshooting

Hello,

I have a Polo 1.6 TDI. It used to run very well. However, it has always consumed 6.3 liters per 100 km instead of the stated 4.3 liters per 100 km. This was the case regardless of whether I was driving 120 km/h or 199 km/h on the highway.

- April 2015: Purchased with 4.5 years of age and 62,000 km. The oil change was not performed until 56,000 km. Purchased from a VW dealer.
- April 2016 - Replaced intercooler (leaking).
- September 2016: Clutch disc replacement.
- September 2016 - Replaced injector 1 due to leakage and loss of power.
- January 2017: Engine parts replacement (due to low compression pressure on 3 cylinders and power loss).

The power loss persists. However, it's only noticeable from around 90 km/h (56 mph). It often only reaches 160 km/h (99 mph), and even with full throttle, it only reaches 162 km/h (101 mph) after 10 seconds. Sometimes it performs better, especially if you stop for a few minutes on the side of the road and then start driving again.

How should I approach this? What should I measure?

Could you please tell me the terms so that I can measure the correct sensors and post them here? I am very new to this, and I would also appreciate book recommendations and suggestions for reading page by page. So, please feel free to share.

Log the following: Speed limiter (driver preference), torque limiter, smoke limiter, average injection quantity, duration of main injection quantity, target and actual boost pressure, exhaust gas temperature before the turbo, and lambda value. The names might vary slightly.
And of course, an automatic scan would also be good, but it would have to be a CAYB engine.

Hello,

I've now taken the following PIDs:

IDE00167
IDE00190-ENG100128
IDE00191-ENG103684
IDE00352-ENG99257
IDE00359-ENG102866
IDE00361-ENG99319
IDE00472-ENG99569
IDE02229-ENG102154
IDE02234-ENG102117
IDE02236-ENG102786
IDE03361-ENG103541
IDE03362-ENG103557

Okay, I'll post the data here for a short "city/highway" drive with a maximum speed of 100 km/h. There doesn't seem to be a noticeable loss of power, but the torque values are quite different. Is this still normal? Especially considering that the torque going to the transmission is almost constantly high?

Hi Alexander,

As you can see, you can't see anything useful with VCScope, especially not with longer logs. Therefore, use KDataScope to interpret logs.
/viewtopic.php?t=16947&start=24#232335

It's much faster with KDataScope, and above all, it provides more meaningful results.

I'll take a look at the uploaded log right away.

Best regards, Rainer.

Edit: Please upload the corresponding raw .csv files instead of the unfortunately uninformative images...

Quote:

...but the torque values are quite different. Is that still normal? Especially because the torque going to the transmission is almost constantly high?

Normally, the speed limit set by the transmission should be the lowest value when using full throttle.
Please also check if the fuel rail pressure can be properly adjusted and if the lambda value is within the correct range at full throttle (1500-4000 rpm).