Underboost Problem Almost Immediately After APR Stage 1 Tune

[Belthasar]

Hi all,

I posted this over on Vortex after getting an APR Stage 1 (87 octane) tune on my '17 GSW 6MT 4mo, but figured this would be a better place to ask for advice, as a discussion about first impressions for the 1.8t/IS12-powered wagen crowd has grown into troubleshooting. I was thrilled with the extra power from the tune, but also annoyed by the prominence of throttle lag. After a few weeks, I started to wonder if the lag was something more than the usual drive by wire laziness. Finally this week, the problem grew into erratic power delivery, as exemplified by a quick video I took:

As you can see, when I give it WOT in second and third, the car accelerates anemically. Note that when I say “There it goes” in the video, that’s when power delivery dramatically increases.

After a little bit more testing after I made that video, the EPC light finally came on and I was able to scan an underboost fault code - P0299. Here's the VCDS log:

1 Fault Found:
14914 - Boost Pressure Regulation
P0299 00 [167] - Control Range Not Reached
MIL ON - Not Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 2
Fault Frequency: 1
Mileage: 50323 km
Date: 2022.12.29
Time: 11:44:23

Engine RPM: 4521.25 /min
Normed load value: 21.2 %
Vehicle speed: 101 km/h
Coolant temperature: 86 °C
Intake air temperature: 13 °C
Ambient air pressure: 1000 mbar
Voltage terminal 30: 14.531 V
Unlearning counter according OBD: 40
Engine: operating status: PL
STATE_BPA[0]: OPM
Charge air pressure control valve position: target value: 0.00 %
Charge air pressure control valve position: actual value: 48.57 %
MAP_MES_SAE: 124 kPa
Charge air pressure control valve activation pulse duty factor: -100.00 %
Charge air pressure control valve voltage: position closed: 3.8965 V

Readiness: 0010 1101

Am I right in reading this that the wastegate is intermittently stuck open? Is "Charge air pressure control valve position" synonymous with wastegate position? I'm fairly new to turbocharged cars, so forgive me if I'm a bit clunky with the terminology.

School me. Anything I can do before concluding it's IS20 time? I have to admit, I went into this thinking an IS20 upgrade would be in the future if something common like the wastegate actuator failed in the next few years. I was not, however, expecting any sort of catastrophic failure immediately after the APR Stage 1 tune.

 

[Belthasar]

I had the chance to gather a little more data today in VCDS. I tried running the following test in VCDS:

IDE04325-Position check of end stops of charge-air pressure actuator

I actually tried this a few times and could never get the test to stop. I would hear the ringing under the hood indicating that the actuator was engaging (but no grinding, buzzing, or otherwise concerning noise), but the test would not terminate. While data logging during this test, I noticed that the specified actuator position would start at 0% and jump to about 88% (makes sense as I assume it's trying to open the wastegate), while actual position of the actuator would remain around 47% the entire time. I had to abort the test each time I tried this after 20 seconds of nothing happening.

I then decided to drive and data log the actual vs specified positions, trying to produce a laggy boost situation and a no boost situation. This was fairly easy to accomplish.

I took off in 1st gear, driving normally with very little throttle.
In 2nd gear, I gave it near-WOT, and boost came on very late (over 4000 rpm)
In 3rd gear, I gave it near-WOT and felt no boost whatsoever

Here are the data from this run:

It seems like the only time the actual position of the actuator reached near 100% was the end of second gear, when boost came on. Not sure about the dip around time stamp 40 (maybe some noise in the data), but this looks like a significant gap in what the ECU calls for an how the actuator behaves. The data in 3rd gear is strange to me, but the gap between actual and specified is still noticeable.

Do these data support a sticking wastegate? What other data should I be logging?

When I get time, I'm going to see if I can physically move the wastegate arm. Am I correct in understanding that if this still moves freely, but the data I'm collecting suggests the wastegate isn't moving as instructed, then it's almost certainly the actuator? But if the wastegate arm feels sticky, it's probably new turbo time? (unless I get lucky with anti seize. I do have a tube of permatex nickel-based on my shelf.)

 

[scrllock]

yep, fix the actuator and get the basic setting to complete successfully.

 

[Diggs24]

That's uhhh....interesting data.

 

[Belthasar]

That's uhhh....interesting data.

Oops!

Attachment fixed. Not sure what happened.

 

[Diggs24]

Get a datazap account and post the log there. Make sure it's set to public.

 

[Diggs24]

Also, other than running the end stops test have you physically adjusted the actuator in any way? The car was perfectly fine prior to the tune and immediately after felt sluggish?

 

[Diggs24]

Last item. Not sure what the ID is in VCDS but if you could also log torque and torque request at the same time. Just search for torque and see what comes up. Could be the tune is hitting torque request until later in the RPMs when the IS12 dies off which is why boost is being limited. Also, add engine speed (rpm) to the log.

 

[Belthasar]

Get a datazap account and post the log there. Make sure it's set to public.

Thanks for the tip! I'll look into them and see about setting up a free account. In the meantime, is the table I posted (and corrected) in Post #2 understandable?

Also, other than running the end stops test have you physically adjusted the actuator in any way? The car was perfectly fine prior to the tune and immediately after felt sluggish?

I haven't touched the actuator at all. And yes, the first thing I noticed after the tune was the throttle lag. I chalked it up to being more noticeable with more power on tap, but the "Persistence" of heavy throttle after lifting off the pedal was always a little strange to me.

I can't for the life of me recall if this behavior was present before the tune. For all I know, it could have been, but I just didn't notice it at stock power levels.

 

[Belthasar]

Here are the requested data, in the preferred Datazap format. Is there a way to embed datazap's interactive chart in a forum post?

I did multiple logs, but this one is probably the simplest. It was a 1st/2nd/3rd gear run, similar to what you saw in the video in the first post. Only difference here is that boost came on in both 2nd and 3rd, albeit with significant lag. Not sure how much deviation is to be expected from intended vs actual torque, and whether these results are abnormal or typical

Thank you for chiming in here, @Diggs24 . Your knowledge on the subject matter is pretty legendary.

 

[Diggs24]

VCDS sampling rate is so horrid. Ok, one more time. 3rd gear so we can get some actual data. 2000 rpm. Floor it and run it out to 5k.

Same parameters as above but need to add boost. I believe VCDS calls it charge pressure actual and specified.

 

[Belthasar]

VCDS sampling rate is so horrid. Ok, one more time. 3rd gear so we can get some actual data. 2000 rpm. Floor it and run it out to 5k.

Same parameters as above but need to add boost. I believe VCDS calls it charge pressure actual and specified.

As you wish, kind sir.

I just grabbed two great logs, I hope.

The first one, linked here, started at a standstill, gently run through 1st and 2nd gears on a highway on ramp. I held it in 3rd gear at 2000rpm and, when I had enough straight open runway, floored it. Got no boost whatsoever through 5000rpms, and the epc light was actually triggered again at 4500 rpm (same code, P0299). I lucked out in the sense that this is only the second time I got this code, and I happened to be logging when it happened.

The second one, linked here, began cruising at 2000rpms in 3rd on a long highway on ramp. When the coast was clear, I went WOT and this time boost came on (albeit after some significant lag). The actual and specified boost parameters in this chart very effectively illustrate the lag.

Hopefully these charts are more illustrative. I look forward to hearing your thoughts

 

[Diggs24]

I think they have a problem with their tune.

https://www.golfmk7.com/forums/index.php?threads/epc-light-p0299-underboost-apr-stage-1.395198/

Take it back to the dealer, log a complaint with APR. Ask to be flashed back to stock and see if the issue persists. Pretty sure they have a money back guarantee or something if you don't like it.

 

[Belthasar]

I think they have a problem with their tune.

https://www.golfmk7.com/forums/index.php?threads/epc-light-p0299-underboost-apr-stage-1.395198/

Take it back to the dealer, log a complaint with APR. Ask to be flashed back to stock and see if the issue persists. Pretty sure they have a money back guarantee or something if you don't like it.

Very interesting. You’re the first person to suggest it might be a software issue. If so, would a reflash possibly solve the issue? I reached out to my tuner earlier in the week. He said there’d be no problem flashing back to stock to rule out software as the problem, free of charge.

What about the data logs suggest that it might be the tune and not the omnipresent wastegate problem?

 

[Diggs24]

It's possible it did fail, but a tune isn't "harder" on an actuator. It uses the full range regardless of tuning. It appears incapable of opening past 49% and then it gets stuck at that position. There are lot so of tables that control the actuator and it's possible that something wasn't changed appropriately or something from another tune/boxcode was copied over thinking it would be ok and instead it causes them to die prematurely. I would certainly try the stock flash since its free. Easy way to determine if it died. if it did, well not a bad time to upgrade to an IS20.