Oil Leak After Fast Highway Drive

Vehicle: Skoda Octavia II Combi, 2012, 103kW/140PS Engine: CFHC

Hello everyone!

Recently, I've noticed that the oil level in my Octavia has been rising. After some research, I thought it might be due to the active particulate filter regeneration. According to this, the oil level should return to normal after a longer drive on the highway, where the fuel is partially burned off. So, I first brought the oil level back up to the maximum by sucking out 0.3 liters, and then I took a drive of about 50 km on the highway, following all the rules of the road and the traffic situation. The oil temperature was between 88 and 96 degrees Celsius. Afterwards, there was an unpleasant surprise: I still had 0.2 liters of oil too much. Therefore, it couldn't be the particulate filter regeneration. Also, I mostly drive long distances. The light for the particulate filter also initially burned out and eventually went out again after a very short run without requiring a special regeneration cycle. Otherwise, the engine is running perfectly.

Do you have any idea what might be causing this? Are there any other testing options to narrow down the error?

Greetings
mcGregg

Was about the issue with the faulty tandem pumps, which led to this error?

The (CHFC) is an EA 189 (i.e., CR), correct? Should not have a tandem pump and PD elements.

If there is an increase in oil level, especially in a situation where {CONDITION} (although I don't know if you have ever checked {COMPARISON}), it can only be caused by a permanently open injector.

Are there any metrics?

matthiasTDI96 wrote:

That (CHFC) is an EA 189 (i.e., CR), correct? Should not have a tandem pump and PD elements. [...]

Absolutely correct.

Here are the measurement values (I hope they are correct):

I wouldn't necessarily consider the Rail Druck calibration points as a measure of an anomaly (my interpretation: they indicate the time at which specific Rail Druck values are reached during the injection cycle, and are used to correct the injection durations).
At least as informative would be the values of the injection quantity deviations at idle, and perhaps the injection/start times of each injection.
If a nozzle doesn't hold, you can best see this next to the LL values by looking at the appearance of the nozzle (= disassembly).
hg
Herbert

Hello Gregg,

If you compare your calibration values with those of other users (see here: /viewtopic.php?t=28779), I would state that your nozzles are leaking and dripping.

Does the box turn blue/black? It may also be due to the tuning, if the rail pressure has been increased via resistance.

Hello everyone!

Thank you for your insightful answers. If I understand correctly, the increase in oil level in the CR Diesel 189 can only occur due to extreme and prolonged short-distance driving (which is not the case for me) or due to faulty injectors. Yesterday, I sucked out another 0.2l, with a mileage of approximately 102,600 km. At 99,300 km, the level was already at the maximum (without suction). Therefore, I have an oil increase of 0.6l over 3,300 km. I now suspect a malfunction.

The strange thing is that the engine runs perfectly and I am quite sensitive about this. I will now contact the seller, I still have warranty. Thanks again for your help, now it's harder to get rid of him.

Greetings
mcGregg

Quote:

If you compare the calibration values with those of other users (see here: /viewtopic.php?t=28779), I would state that your nozzles are leaking and dripping.

Please, could you explain exactly what you are detecting? For me, the values are within the range of reports for R4 engines in the link. In my opinion, we don't even have clarity on the measurement principle. You can see, for example, that calibration points 2 sometimes lie before calibration points 1.
hg
Herbert

Hello Herbert,

I have to agree with you (unfortunately). That was nonsense. I have now realized,
that the calibration values are used much less for the actual quantity limitation, but rather to smooth out pressure fluctuations in the system.

There is a Dr. paper that I unfortunately cannot publish here, from which it emerges that the "on-time" that has been calibrated only refers to the correction of pressure waves. This effectively smooths out pressure waves.
This all happens in the 0.001 millisecond range.

For those interested: You can find this topic under: "Injection Quantity Correction in Common Rail Systems Using Magnetoelastic Pressure Sensors"

According to my research, the response times (from the control unit) can range up to 1.4 ms, which is normal.
Corrections such as those mentioned above, an injector delay of approximately 0.040 ms, would therefore not be significant.

My knowledge of pneumatics is not sufficient for validation purposes. That's "higher" mathematics...