Advice needed-fuel delivery? Rough idle, stalling - 06 jetta 2.0t bwa

[Danai89]

Hi all,
At a loss and keen to hear people’s insights.
Picked up a 2006 jetta fsi turbo with the 2.0 gti engine and 220tkm. It was barely running and blowing lots of smoke etc. Thought it could a project for me and a coilpack etc might be the misfire issue and a quick fix.
So over the last week or so I changed the following:
- Replaced fake r8 coils with genuine factory ones and cleaned and re-gapped plugs to spec (no change in running condition after this step)
- noticed a current bhs pcv delete setup in place with broken original hoses, so changed back with new original pcv setup incl all new hoses
- did intake carbon clean incl throttle body, cleaned all sensors and plugs
- replaced all engine vacuum lines, as brittle and cracked/loose
- cleaned maf and also swapped in another genuine maf - no difference after doing today’s test starts
- cleaned and tested fuel injectors
- checked cam follower


Started her up and apart from no more smoke out of the exhaust, she still ‘runs’ as bad as before. Struggles to fire up every now and then, and then super lumpy and boggy, often just stalls or if i try to accelerate, she slowly increases revs but with hesitation and then just stalls again as soon as one drops revs etc. best I can describe it is like running a 2stroke outboard that has fuel starvation and no power and stalls, due to fuel tank vent etc not open. I.e poor fuel delivery to motor.


So I thought I might check the fuel pressure values and I have run vcds as best i could during a start up where i could keep her running for a short period and by accelerating and not stalling straight up.


Currently on the phone, so can’t post pictures but tried to include a video below, and
Before start up the group values for the following were:
Group 103 low pressure fuel pump: 5.46bar; -1417 fuel pres regulator; adaptation value elec fuel pump -1
Group 106: fuel rail pressure 59.25bar ; elec fuel pump 1: 5.9% ; time 97s
Group 230: rail pressure 50bar; actual rail pres 59.34; rail pres difference -9.28


After giving her a rev up and trying to hold her at around 4000rpm with difficulty, I got following values
Group 103 low pressure fuel pump: 4.56bar; -550 fuel pres regulator; adaptation value elec fuel pump -3
Group 106: fuel rail pressure 109.81bar ; elec fuel pump 1: 51.4% ; time 102s
Group 230: rail pressure 109.99bar; actual rail pres 109.76; rail pres difference 0.23


Not sure if this helps, but after all the above changes, i thought maybe i have a fuel delivery issue, as I cant think of anything else anymore.


Any advice would be much appreciated, or what else to look at. Car is not drivable at all with this issue and no fault codes come up, as i assume they were reset by seller (if any were present) and car did not have enough run time to log any again.
Thanks. Dan

[MIG]

Your fuel deviation and pressures look ok, within the 5 bar specified and actual when running.

Check your short-term and long-term fuel trims, as it might be an air metering issue; next I would be checking the timing looks right.

some helpful stuff from VCDS on that engine
2.0l TFSI (AXX/BGB/BPJ/BPY/BWA) - Ross-Tech Wiki

[Danai89]

Thank you MIG.
i managed to look at the fuel trims today, thinking they would all be in order/reset after battery being disconnected as well as fault code resets.
However, following the rosstech video, I noticed that upon start up and idle, including reving, the vslues do not mote from ‘0’ at all. As if they were faulty/not getting a reading.
any idea what could cause this? This could most likely be the issue, that nothing is compensated for.
here a quick 5sec video again with values not moving from 0 at idle

https://youtube.com/shorts/p1HMwCfjRZ4?feature=share

Your fuel deviation and pressures look ok, within the 5 bar specified and actual when running.

Check your short-term and long-term fuel trims, as it might be an air metering issue; next I would be checking the timing looks right.

some helpful stuff from VCDS on that engine
2.0l TFSI (AXX/BGB/BPJ/BPY/BWA) - Ross-Tech Wiki

[MIG]

For both values to be zero, something is not right. One of the sensors the ECU uses to calculate fuel trims might be missing.

Check the MAF reading; this is in block 2 (The value at idle should be between 1 and 25 g/s); not saying the MAF is faulty; there might be an air leak. Is the exhaust fumes like it's running rich?

Are you sure there are no fault codes?