Azure Blue - A2 FSI Faults and Fixes

[PlasticMac]

Hope you can get it running again. If so, try this:
With a hot engine, check Group 001.
Look at Block 4. You'll see a string of 8 numbers, either 1s or 0s.

Look at the first two from the right.
XXXXXX??
The first will be 0 if you have no engine DTCs. The second will be 1 if the Cat is up to temperature, (measured by the exhaust temperature sensor).
If the Cat is not up to temperature, the ECU will take action to get it hot, (advancing ignition, richer mixture, etc).
If the Cat is up to temperature, but the exhaust sensor is, incorrectly, telling the ECU it isn't, symptoms similar to yours are likely.
Edit: Engine running with a lean/weak mixture will also give a low exhaust/cat temperature, which will not be obvious when the engine is cold, because the mixture defaults to rich.
Once the engine is hot, the enrichment ceases, and the symptoms of lean mixture will show up.
If you think this fits your car, carry out a throttle body adaptation.
The ECU sets the mixture, on the advice of the lambda. It uses throttle valve angle, and injection timing to do that. If the throttle body is not "matched" to the ECU, the physical throttle angle may well be different to the angle reported to the ECU. That means the throttle control will be offset over the whole operating range. Resulting in a weak, or rich mixture, depending on the direction of the offset.
Mac.

 

[PlasticMac]

Good Morning Mac,

I come back to this. As I see it the EVAP system discharges into the upper manifold which is before the flaps.

Andy

While looking at nearby parts, I noticed that the EVAP/N80 System discharges into the elbow between the throttle body, and the EGR inflow, not into the lower inlet manifold. Well before the flaps. Via part 54 below.
Mac.

 

[lavandism]

While looking at nearby parts, I noticed that the EVAP/N80 System discharges into the elbow between the throttle body, and the EGR inflow, not into the lower inlet manifold. Well before the flaps. Via part 54 below.
Mac.
View attachment 137564

curiosity; so EGR is almost next to TB on FSIs?

 

[PlasticMac]

curiosity; so EGR is almost next to TB on FSIs?

Yes, TB 19, EGR 25, Tank Vent/N80 50:

 

[AndyBa]

Sorry I haven't responded to this. I have taken some more traces on the lapdog but my attention has been on work and the house. I've borrowed my son's Corsa for a while since my Golf needs the subframe replacing.
I did ring WOM up to book it in. They said send an email, but their mail portal isn't working. The guy asked me if I had got any real temperature readings which I have. I'll share my readings soon.

 

[AndyBa]

An update....The Corsa maybe boring but it's so nice to get in a car an it start first time and not have to worry about getting stuck anywhere!
The Golf has had a replacement subframe fitted but now needs the steering alignment doing.....as well as a service. It keeps completely cutting out. Noted the coil-distributor cable snapped, fortunately I was able to pull off the 90 degree angle connector and reveal the straight connector and drive it home!
As for the A2, it is still at my Son's. It is now booked in at WOM for 2nd June, here's hoping they can fix it. I do need to swap the fuel pump since the one that is in reads in reverse since swapped - Have seen an old post which indicates that the fuel pump is incorrect https://www.a2oc.net/community/index.php?threads/fuel-gauge-issue.38709/#post-428441
I've added the last trace post O2 sensor replacement.

 

[PlasticMac]

The log shows that the lambda control is not active.
Group 001, Block 4 is a string of 8 digits.
Even at the end of the drive, the bit for lambda control status is not set. You have:
11000011. The fourth from the left hand is lambda control status. It should be a 1, but is a 0.
That, probably, means the lambda is not controlling the fuel/air ratio, which it should be. Needs diagnosing.
Mac.

 

[PlasticMac]

The log shows that the lambda control is not active.
Group 001, Block 4 is a string of 8 digits.
Even at the end of the drive, the bit for lambda control status is not set. You have:
11000011. The fourth from the left hand is lambda control status. It should be a 1, but is a 0.
That, probably, means the lambda is not controlling the fuel/air ratio, which it should be. Needs diagnosing.
Mac.

For more on the pre cat lambda:

Group 030,0,Lambda Control (Lambda Sensor Status)",,
Block 1,Status,sensor 1
-xxx1 = Lambda control active,
-xx1x = Lambda sensor ready for operation,
-x1xx = Lambda sensor heater on,
-1xxx = Cat. clearing active

Group 031,0,Lambda Control (Lambda Sensor Voltage)",,
Block 1,Sensor 1,voltage (actual)",,
Block 2,Sensor 1,voltage (setpoint)
Mac.

 

[AndyBa]

An update.
I put the original in-tank fuel pump back in so the fuel gauge now reads correctly. Starting from cold is still the same, but starting from hot "seems" better, probs luck more than anything....monitoring.
Will see what WOM say w/c 2nd June.