Any ideas what is causing this?

[N871BUD]

hello everyone, anyone encountered this:

- YouTube

2016-2017 CRLB engine 150hp paired on a manual gearbox no faults in ecu neither pending or historic.

Things already checked: injector leak of test as per vw instructions.
Fuel filter changed, fuel filter cannister checked for any potential deposits.
Air filter checked chenged few times, mas airflow meter checked.
Battery is varta as per spec and was coded into the car and is less than 2 years old.
Can happen random even with a hot half to temperature or cold engine.
Car is kept90% of time with over half of tank of diesel, this happens regardelessof fuel either premium diesel normal etc.
It can happen for 2 consecutive days runs or with a week apart so no patern there, it done it for about 5 minutes when i done the video and done it next day 30 miles later... and since done it 500 miles later again today.
This happens since January over a span of 15-17k miles.
I hope i have not missed anything i already checked and tried...

any idea welcome...

[Crasher]

That looks like a failing injector, view the balances.

[N871BUD]

I am in doubt about injectors, long story short: injectors replaced with remanufactured ones and old ones sent to be checked and returned ok after a clean. And yes problem persisted.

Later add: https://youtube.com/shorts/nhb284jJo...sJr96EcjPObhBW

Took a bit to get to this as i did not had time and in the proces i replaced the cover gasket and afiliated seals( a overdue job)

Lately i noticed that the fuel relief valve on the common rail plug was moving quite a bit, and decided to put a drop of glue to stop it moving, that somehow affected the way the engine behaved in the moments was starting the above in the video. Rpm would not jump all over the place anymore atleast not something you would notice visually on the dash but a engine noise was still present. My local skoda did only sell the whole rail assambly with the valve and pressure sensor... so i ordered that. Now the mpg went up car seems fine but something is still not right as sometimes idle fluctuates for a split second and when that happens the car is dead in terms of power for 3-5 seconds and if from a standstill engine will stahl. Still no registered codes of any kind.

I noticee i can recreate the fault even before chamging the injectors by driving the car a good 40-50 minutes; park it up; start driving after 20-30 minutes again and will happen in the first 2 -5 minutes.

[Crasher]

Remanufactured by whom?

[N871BUD]

WTDiesel

I still have all 4 old ones, acts the same only difference i noticed the the mpg whent up by 5-8 mpg using same route daily. Changing the rail with the sensors affected the rev counter bouncing to the point that if you do not look at it very closely you would not notice a variation, is no point posting a video for that as would not register on camera as is so small. The change of sound is still obvious if i am on idle tho.

My first thinking was that cannot be a completly different set to act exactly the same as before. The "new" injectors came with new codes to code into the ecu and all accepted and seems the deviation in live data are very close to 0 compared to before thatthey were touching 0.9. Based of what i found when coding the new ones, i believe one injector was pulled out before and replaced as was coded wrong instead of 1 was a I so probably that would explain the mpg jump that i have now.

Just before replacing the rail becouse of the relief valve, i had a few instances after parking the car with a hot engine and wanting to drive again would stahl on me guttless 3-4 times and restarting again by itself again with no codes. This did not happen anymore in the last week since changing the rail with the valve. Now i am doing almost every trip with the laptop and vcds on in hope when the behaviour is back i can pull over or something and hope it lasts long enough that i can check some rail pressure readings and maybe temperatures. So far when it happens is so short 10-20 seconds that i cannot get to check anything.

[Crasher]

We will only fit new VDO, Bosch or Delphi (as appropriate) after many bad experiences with recons.