p0171 system to lean ... over 2 years now ...

[Badej]

Welcome !
At the beginning I am sorry in English and with errors.

After two years of fighting (with breaks) I decided to ask at the source :).

 

Skoda Superb 2.0 TSI with DSG.

From two years, from time to time Chceck Engine control appears with error P0171.
In addition to the appearance of the light itself, the car behaves completely normally.

 

Therefore, I want to sell the car. I decided to remove the "failure",

unfortunately it did not turn out to be easy.

During this time I have already replaced:

- Lambda probe
- Spark plugs
- Fuel filter
- Engine odor (crankcase breather)
- Fuel tank vent valve
- I have also updated the main computer and gearbox driver software

 

Unfortunately it did not give any results and the error keeps coming back.

Has anyone ever encountered such a problem?

Thank you in advance for all suggestions.

 

 

greetings
Maciek

[marek16]

hey, unfortunately you keep replacing things that have nothing to do with your problem.

"System lean" fault means there is "too much air or too little fuel" in the mixture. This can be a real (physical fault) or perceived by the ECU (faulty sensor) problem.

Most commonly this means there is a hole in your air intake subsystem. Check all the hoses, air pipes, intake module and all of their connections. If you see a hole, rupture in some seal or disconnected hoses - there you go.

 

Very nice video on the subject: https://www.youtube.com/watch?v=mM6j7E5vE7s

 

Some other possible causes (fuel supply insufficiency, etc): http://wiki.ross-tech.com/wiki/index.php/16555/P0171/000369

Editováno: 15. Srpen 2019, autor: marek16

[Badej]

Thank You for replay !

At the weekend I tried to check the things you wrote about.

Unfortunately, as we say "I have two left hands" when it comes to mechanics.

The only strange thing about the intake system is the "moisture" that can be seen in the pictures.

 

 

 

I have to go to a professional workschop to check the tightness of the intake system.

[rayx]

Could be top oil separator, its main diaphragm ;-) latest part 06H103495AJ

 

https://youtu.be/jTSQoMtNksQ?t=487

[Badej]

4 godziny temu, rayx napisał:

Could be top oil separator, its main diaphragm ;-) latest part 06H103495AJ

 

https://youtu.be/jTSQoMtNksQ?t=487

 It was also replaced to. :/

 

I'm going to the workshop on Thursday. We check the tightness of the intake system. It will be the fifth workshop in two years. Skoda authorized service was the first to give up.

Editováno: 19. Srpen 2019, autor: Badej

[Tomas F]

I have noticed this moisture "problem" on my 1.8 TSi too but there is not such error you mentioned. Regardless to change of the oil separator and some sealings, this still appears on the same place without any effect to the engine. What I want to say is that the moisture may be another problem and has nothing to do with your error code.

 

One question - car diagnostics usualy write down RPM, engine load and other things. Have you noticed some common conditions associated with your error code?

[Badej]

8 godzin temu, Tomas F napisał:

One question - car diagnostics usualy write down RPM, engine load and other things. Have you noticed some common conditions associated with your error code?

 

Unfortunately, I did not follow any rules when this error occurred.

Sometimes it appears after 300 kilometers from extinction. Sometimes after 50 kilometers. Regardless of the level of fuel in the tank,

engine temperature, outside temperature, speed or RPM.

 

The only "pattern" that appeared was when it was detected that one of the wires leading to the turbine was cracked,

which caused a weaker charge. After replacing this cable, the error (p0171) was lit non-stop for some over 3,000-4,000 kilometers until I changed the top oil separator.

Then the situation returned to the point where the error occurs and disappears from time to time.

[Badej]

Update:

There is no any cracks or holes in intake system. All good and tight with it.

I don't know what to check now ...

[Tonda-B]

Mass Air Flow Sensor could be faulty.