TDI Specialist Needed: Help with Skoda TDI RS!

Hello fellow diesel enthusiasts,

I've been struggling with a 2007 Octavia RS TDI PD for about a year now. It has the BMN engine with 170 horsepower and currently has 245,000 km on the odometer.

I bought it with 156,000 kilometers on the clock, and it ran terribly. From a standstill, the wheels would spin due to all the power. Then I had the stupid idea of taking it to a tuner. For 6 months, the RS ran incredibly well, but then suddenly, intermittently, there was power, then no power; in bursts, as if the turbo couldn't hold the pressure. A friend said it was definitely the turbo. So, I bought a new one, including the intercooler.

After exchanging many parts and now even using original 2148 software (I tried the 4366 version from a Golf in between, but without success), I still have a problem that I can't seem to fix, and apparently neither can anyone else. I would appreciate your help.

Below 2500 rpm, the car doesn't have any power, regardless of the gear. It lacks proper acceleration and struggles to reach higher RPMs. In 5th or 6th gear, it's so bad that I sometimes have to downshift because it just won't move forward.

"It runs smoothly at around 2500 rpm without any hesitation, but it's missing an estimated 40 horsepower. I can't get the fuel consumption below 6.5 liters per 100 kilometers even when using cruise control. I'm so desperate and frustrated that I don't even want to seek free advice anymore. I would even be willing to pay for help from a TDI expert among you."

Here's what I've done in the past approximately 1.5 years since purchasing the car: turbocharger replacement, intake manifold with swirl flaps, dual-mass flywheel (replaced recently), DPF (Diesel Particulate Filter) replaced 4 weeks ago, EGR valve (replaced today), throttle body cleaned, wiring harness in the cylinder head for the injectors (replaced 3 weeks ago), MAP sensor (new), pressure sensor on the swirl flaps (new), N75 valve replaced, front magnetic solenoid valve replaced, new battery, air filter, checked and adjusted the timing belt a few times, regular oil changes, diesel fuel filter replacements.

Occasionally, the car would display a message indicating that the "charging limit had been exceeded," but only about every six months. The major issues with the discrepancy between the target and actual boost pressure likely stemmed from the DPF, which was clogged with 87% ash and wasn't reporting it. This probably restricted the turbocharger. Furthermore, I would say quite clearly that the power loss is increasing significantly with rising outside temperatures.

My suspicion is that there's some kind of vacuum issue or something preventing the VTG turbocharger vanes from adjusting properly. Unfortunately, I don't know how to fix it. I've been searching for months and haven't found anything. Oh, I also suspected the vacuum pump, but I don't notice any difference in brake pressure, as the pump is also responsible for the BKV (brake control valve).

PLEASE: Can anyone help me before I set the car on fire? I'm really at my wit's end. By the way, I'm located in the middle of Hesse, in the district of Limburg an der Lahn.

Without a log file, it's difficult to say anything.

Create a log of the MWB 003-008-011, running it from 1500 RPM to 4000 RPM in either 3rd or 4th gear.

Thank you for your reply.
I can do that if I get a chance to use the VCDS software again sometime. I would really appreciate any tips you have.

Okay, here I am again.

"Sorry that my responses are taking a while. I've been traveling all week and can only work on the car during the weekend."

Today I replaced the water temperature sensor again, of course, just guessing this time, and as always, without any noticeable improvement. The hotter it gets outside, the more my car acts up; warm air means no power, while cold air results in a noticeably better performance. I'm not talking about a slight difference here.

Here are the requested VCDS data logs. The first log is from fourth gear at full throttle (slight incline), the second is from third gear at full throttle (steeper incline), and the third is from first gear, starting from a standstill (but going downhill).

Perhaps one of you can offer some insight into where I should start.
Oh, I saw from below that my loader is leaking oil. It seems to be coming from the oil line. I'll have to fix that sometime in the next few days. I completely rebuilt the loader a while back, but I didn't replace the oil line as specified.


UPDATE: I also found the old problem he occasionally has every few months. I'm driving up a steep hill, in fourth gear, at a medium RPM, with full throttle, and then suddenly the warning light comes on.

000665 - Charge pressure control.
P0299 - 006 - Control limit exceeded - Intermittent.
Environmental conditions:
Error status: 00000001
Error priority: 5.
Error frequency: 1.
Lost Count: 38
Mileage: 206,314 km
Time: 0.
Date: 2000.00.00
Time: 18:13:05

Environmental conditions:
Speed: 2304 RPM
Torque: 328.0 Nm
Speed: 102.0 km/h
90.48%
Voltage: 14.01 V
Pressure: 2449.5 mbar.
Pressure: 1980.9 mbar.

There is a Technical Problem Investigation (TPI) document available for the P0299 error code on the BMN engine.
It states that the cause is resistance in the motor wiring harness.
The temperature dependence described here is consistent with that.

Remedy:

a) verschandeln the mass points.

All ground connections in the engine compartment should be checked, especially those located in the coolant reservoir and on the longitudinal supports. Ring terminals that are possibly twisted or not making full contact at the ends of the cables are particularly suspect. Even seemingly verschandeln contact surfaces should be cleaned. Afterwards, treat them with a protective wax.

b) Install the repair lead set (1KD 971 658)

Disconnect the MSG, unplug the connectors. Disconnect the connector on the pressure sensor (G31/G42) and secure it away from the socket. Disassemble the 94-pin connector housing for the MSG. Push out the pins for the boost pressure sensor (G31) and intake air temperature sensor (G42). The pin assignments for the wiring to G31/G42 in the 94-pin connector are shown in the wiring diagram -> Erwin.

Route the U-shaped repair harness cable approximately above the transmission, from the front of the engine to the rear of the engine. Engage the pins of the repair harness into the corresponding clips of the 94-pin connector and reattach the 4-pin connector to the G31/G42.

c) Software update for the MSG

Hello Roger,

"BOMBE" - those are some compelling points, although they do concern me a bit. How is someone supposed to implement that (especially outside of a professional workshop)? Should I perhaps take the car to Skoda with this information?

Has anyone of you ever taken a look at the logs in between? I'm not an expert, after all. Is it still possible to glean anything from them?

BTW: Update for the MSTG? According to my Skoda dealer, 2166 is the only available version. I once had version 4366 from a Golf TDI installed, but then it no longer communicated with the gateway, and I couldn't proceed any further. The error persisted even with version 4366.

Thank you very much.

Sure, here is the translation of the text from German to English:

"Hi Spaxs,"

We once went on a logging trip together. What happened to your Octavia and the problem you were having? Did you find a solution?

For everyone else. I eventually replaced the DPF with a new one and several other things, and then everything was quiet. Nowadays, I drive a Seat Leon FR ST. It's also running .

It's understandable that there would be problems with the boost pressure control if it's completely full... Were there any issues related to the DPF?
Apart from obvious things like exceeding the maximum allowable ash content...

"Yes, of course, the ash mass was too high. The previous owner had already let the DPF burn out once. Therefore, the measured values were actually not high enough for a replacement, at least not the ones calculated in VCDS. However, the differential pressure was no longer correct, and after a forced regeneration, it improved somewhat. I then removed the DPF."
However, there were other issues as well. The differential pressure sensor apparently had some problems, and I replaced a few hoses and a handful of those small solenoid valves. Also, I replaced the actuator assembly with its housing for the swirl flaps located under the timing belt cover.
I have no idea what it actually was in the end. So, it's difficult to give any specific advice if someone else experiences something similar. I couldn't clearly identify any issues based on the values displayed on the tester.

So, if you're not really capable of doing your own repairs and are experiencing similar issues, I would almost advise selling the car. Not even the Skoda workshop managed to fix it; they didn't get usable results, not even during a test drive with the workshop manager. And on top of that, they always charged exorbitant amounts for labor. I wouldn't do that again.

Well, I'm not sure, but if the DPF is completely full, you can either have it cleaned (DPF-Reinigen Fachartikel) or replaced at a workshop. There are also refurbished DPFs available for replacement, and the cost and time involved are usually manageable.

If I have a manure pit, then I should empty it sometimes before everything overflows during the flushing process and spills out over the toilet seat, and then I shouldn't look surprised.

We had searched together for the error in the depths of the bits and bytes, and also conducted several test runs. However, we both had limited time, so we were unable to conduct a systematic troubleshooting process.

Apparently, all the read-out values were fine, especially those related to the DPF, which we checked together. What we missed will likely remain a mystery forever.

In my case, the DPF values simply weren't plausible. The calculated ash mass was too low to justify a replacement, but the differential pressure was too high. It looked like something was blocking it. As mentioned before, the specialized workshop wasn't helpful at all in troubleshooting the issue. They only made vague guesses, which I had to pay for.

By the way, my DPF was one I bought from eBay for €399, brand new. It wasn't a perfect fit, so I had to enlarge one of the two holes in the bracket before the fuel injection system, but after that, it was all good. If you know that you can remove the metal tunnel to avoid having to disassemble half of the front axle, then the job is also quite quick.

Quote:

The calculated ash mass was too low for a swap.

You can also set the ash mass to any desired value without having to remove the DPF at all.
It's conceivable that there was some manipulation involving multiple owners if the value is surprisingly low. Usually, the calculated value is either about right or even too high.
At least, unless something fundamentally goes wrong that contributes to the formation of ash, such as poor fuel quality, unsuitable engine oil, or damage resulting in high oil consumption.

Is it possible to determine the fill level of a DPF without knowing its history or operating conditions?

What I experienced, no. However, you can probably get a good indication by looking at the differential pressure; it will likely show when nothing is flowing through anymore. That was the reason for me to replace it. When I initiated a forced regeneration and drove a few meters, it only got slightly better. In other words, I could tell that it wasn't releasing properly.