Underboost Problem Almost Immediately After APR Stage 1 Tune

[Belthasar]

For the IS12 and IS20 - key on/car not running....

WG acknowledgement should be 2.0

WG lower stop should be 3.6

For IS38 it's 3.6 and 3.6

IS12/20 WG isn't tightly closed in the on position, it's loose.

Sounds to me like you may just need a new turbo here.

My understanding is that the CTS turbo replacement IS12/20/38 actuator (the one I bought, which is interchangeable on all three turbos) is the pre-face life IS38 design. So ignition ON, the wastegate should be shut, which I just verified is true.

 

[tigeo]

My understanding is that the CTS turbo replacement IS12/20/38 actuator (the one I bought, which is interchangeable on all three turbos) is the pre-face life IS38 design. So ignition ON, the wastegate should be shut, which I just verified is true.

No clue man - I'm going off what the stock turbos/WGs should be set at.

 

[Belthasar]

No clue man - I'm going off what the stock turbos/WGs should be set at.

Likewise. I’ve seen many instructions (3.5-3.9v, 3,6v , etc). I’ve tried 3.71v, 3.6,v, 3.45v - all passed first adaptation on the first shot. And none of these preloads made any difference.

 

[tigeo]

Likewise. I’ve seen many instructions (3.5-3.9v, 3,6v , etc). I’ve tried 3.71v, 3.6,v, 3.45v - all passed first adaptation on the first shot. And none of these preloads made any difference.

My IS38 is at 3.99, runs fine. It's a range of 3.4-3.99 basically for the lower stop.

Have you logged this car and spoken with APR?

 

[Belthasar]

My IS38 is at 3.99, runs fine. It's a range of 3.4-3.99 basically for the lower stop.

Have you logged this car and spoken with APR?

Yes. APR’s take is that my wastegate actuator was marginal prior to tune, and that the tune pushed it over the edge. My logs earlier in this thread support that the wastegate wasn’t properly
Functioning, and that it was once I replaced it with the CTS actuator. The new logs (also earlier in this thread) show that the actuator is aligning almost perfectly with specified values. There’s a lag between intended boost and actual boost. Some think that’s normal turbo lag, but seat of the pants feel says that a full second of no response at WOT is not normal (and a huge decrease in fun-to-drive factor).

No advice regarding the new rattle, nor the annoying input lag that persists even after WG and DV replacement. My tuner says that the apr tune is actually supposed to remove lag, and that the “over run” is highly unusual.

 

[Belthasar]

Question for the mind hive: Is this sound normal?

This is what I was referring to in post #32 when I described there being multiple beeps after turning off the car. This was after a spirited spin around the block, a few seconds after turning off the engine. This is the wastegate actuator beeping. Prior to replacement, I can't recall if I ever heard it sound like this after a drive.

 

[tigeo]

100% normal to get some of those noises.

 

[Belthasar]

100% normal to get some of those noises.

Good to know. I don't remember it beeping repeatedly before I replaced the WGA, but different unit, different design, so different noises are to be expected.

The crunching/rattling noise under load, however, is definitely not normal. Even my wife noticed it, and she never notices anything out of the ordinary on cars. At first she thought it sounded like crunching leaves, but earlier today asked me if something metallic is rattling.

 

[tigeo]

Good to know. I don't remember it beeping repeatedly before I replaced the WGA, but different unit, different design, so different noises are to be expected.

The crunching/rattling noise under load, however, is definitely not normal. Even my wife noticed it, and she never notices anything out of the ordinary on cars. At first she thought it sounded like crunching leaves, but earlier today asked me if something metallic is rattling.

Clearly you have some kind of hardware issue (sounds like turbo/WG-related) here that pushing more boost with the tune brought out. There are quite a number of folks that had their IS12/WG shit the bed after tuning with APR seeming to be the common denomiator - that isn't in any way scientific or a slight on APR, they make good tunes but pushing that tiny turbo harder is going to do that at some point. With that said, a ton of folks on APR stage 1 on the 1.8 with zero issues.

 

[Belthasar]

Clearly you have some kind of hardware issue (sounds like turbo/WG-related) here that pushing more boost with the tune brought out. There are quite a number of folks that had their IS12/WG shit the bed after tuning with APR seeming to be the common denomiator - that isn't in any way scientific or a slight on APR, they make good tunes but pushing that tiny turbo harder is going to do that at some point. With that said, a ton of folks on APR stage 1 on the 1.8 with zero issues.

Precisely, but as the narrative of this thread has documented, I have a brand new WG actuator installed, and the flapper arm, bushing, etc. all move freely. My data logs all show that the WG is now functioning properly. If the new WGA is the source of the metallic rattle, there's nothing obvious that points to it.

I'm not even sure if this annoying sound has anything to do with the irritating lag that just won't go away, either.

If something with the tune broke something else with the turbo, any ideas what would rattle slightly under load? This would mean that the tune immediately toasted my WGA, DV, and a third component, if true. Not a good look on APR's part.

 

[tigeo]

Precisely, but as the narrative of this thread has documented, I have a brand new WG actuator installed, and the flapper arm, bushing, etc. all move freely. My data logs all show that the WG is now functioning properly. If the new WGA is the source of the metallic rattle, there's nothing obvious that points to it.

I'm not even sure if this annoying sound has anything to do with the irritating lag that just won't go away, either.

If something with the tune broke something else with the turbo, any ideas what would rattle slightly under load? This would mean that the tune immediately toasted my WGA, DV, and a third component, if true. Not a good look on APR's part.

I have no clue man - do you have a log here you can post that shows all of this (maybe you did that above somewhere that I missed)? Blaming the tune here is mis-guided simply b/c there are many folks with no issues at all. Here, you clearly have something mechanical wrong and we just figured that part out.

Have you flashed back to stock to see if these issues persist?

I can't recall now b/c we are at 5 pages - DV was bad too?

Any good videos with all this documented?

 

[Belthasar]

I have no clue man - do you have a log here you can post that shows all of this (maybe you did that above somewhere that I missed)? Blaming the tune here is mis-guided simply b/c there are many folks with no issues at all. Here, you clearly have something mechanical wrong and we just figured that part out.

Have you flashed back to stock to see if these issues persist?

I can't recall now b/c we are at 5 pages - DV was bad too?

Any good videos with all this documented?

I wouldn't say that blaming the tune is mis-guided. My tuner's APR rep was the first to suggest that the tune toasted an already-marginal WG, and the legendary @Diggs24 himself first suggested it might be a tune issue (before I flashed back to stock and confirmed hardware issue), and his current theory (regarding the front end lag) is that it's the nature of the beast with an 87 octane tune (pulling timing at sudden WOT). Given how jarring the full-second throttle lag is, I'm not entirely convinced of that theory, and it doesn't explain the rattle. Regardless, all of this narrative is documented in this (now lengthy) thread.

Yes, I flashed back to stock a few weeks ago. Page 2, post #18. That's how I finally got the P0299 code and confirmed WG or DV was bad.

DV was likely bad, too. Page 4, post #54.

I do have a log here. A few of them:
Pre WG replacement data - Page 3, Post #33
Post WG replacement data - Page 4, post #48

I did take a video before I replaced WGA - Page 1, Post #1. Though that's outdated now since WGA has been replaced and the lag has been reduced to a consistent second or so.

It's all in this thread, over which I don't think I blindly blame the tune. Rather, I'm trying hard to diagnose a gremlin that has been persistent since day 1 after my tune (so naturally, the topic of the tune is a common one in this thread and the timing is suspect). I'm also trying to do this in a well-documented manner that may help someone who experiences the same frustrations as I.

 

[tigeo]

I wouldn't say that blaming the tune is mis-guided. My tuner's APR rep was the first to suggest that the tune toasted an already-marginal WG, and the legendary @Diggs24 himself first suggested it might be a tune issue (before I flashed back to stock and confirmed hardware issue), and his current theory (regarding the front end lag) is that it's the nature of the beast with an 87 octane tune (pulling timing at sudden WOT). Given how jarring the full-second throttle lag is, I'm not entirely convinced of that theory, and it doesn't explain the rattle. Regardless, all of this narrative is documented in this (now lengthy) thread.

Yes, I flashed back to stock a few weeks ago. Page 2, post #18. That's how I finally got the P0299 code and confirmed WG or DV was bad.

DV was likely bad, too. Page 4, post #54.

I do have a log here. A few of them:
Pre WG replacement data - Page 3, Post #33
Post WG replacement data - Page 4, post #48

I did take a video before I replaced WGA - Page 1, Post #1. Though that's outdated now since WGA has been replaced and the lag has been reduced to a consistent second or so.

It's all in this thread, over which I don't think I blindly blame the tune. Rather, I'm trying hard to diagnose a gremlin that has been persistent since day 1 after my tune (so naturally, the topic of the tune is a common one in this thread and the timing is suspect). I'm also trying to do this in a well-documented manner that may help someone who experiences the same frustrations as I.

Ok appreciate the look-backs. The logs - too bad you only recorded a few things, would be interesting to see the rest of the typical parameters.

My comment regarding the tune. The tune doesn't toast anything here, I prefer to say that it can exploit existing weaknesses as all tunes will. As I mentioned above, APR's tunes have had a nack for pushing the little IS12s with WG issues/failures and it may have been any tune that would have the same effect. The lag...no idea man, I've never heard of anyone saying the APR stage 1 tunes were in any way laggy. Any tune wil push more boost and cause it to feel different than stock but the stage 1 tune I had (Uni 93) never had any delays that I would discern...more like insta-boost! Excessive timing correction for the 87 tune has no basis, no logs I've seen of that tune showed that at all. There is a user here that was tracking his APR-stage 1 (87) wagon at Laguna Seca with no drama at all.

I hope you get it sorted man.

 

[Goodbar]

I have the same car (GSW 4Motion, 6MT, though 2019) and same tune (APR Stage 1, 87 AKI, no bolt-ons, original turbo) and got the same P0299 00 code with the EPC light on the dash. This is particularly inconvenient because we're on a multi-day trip with the kids and dog in tow. The car has been tuned for about 2 years and this is the first occurrence. While driving up the hills in Western MD on cruise yesterday, the car started losing speed, then suddenly boost would hit and it would recover to the set speed. I stopped using cruise and figured out if I lifted off the gas and re-applied, I'd get boost about 90% of the time. (Power seems normal under boost.) The EPC light came on in the first hour or so and I cleared the codes within a few minutes. We continued driving another 6 hours and there were no codes this morning.

I ran the output test in VCDS to operate the diverter valve and it clicked. The wastegate actuator doesn't appear to be going through its full range using the end stops function in VCDS (don't have the exact verbiage in front of me). It goes to 0% specified and ~2% actual, then gets stuck at 44% actual (see screenshot) on the way to 90%. Assuming that means the WGA is failing? I reached under the turbo and was able to move the WG rod a little bit. I also visually inspected it in the last year and there was no evidence of corrosion. I don't think the WG is frozen, but haven't been able to confirm definitively yet.

I'm flying to a conference and my wife is driving the car home, so trying to determine the worst case scenario. Suffice it to say I'll be on her shitlist for a while if the car breaks down in the middle of nowhere with the kids in the car.

Thanks for insights, y'all!

PS: I feel your frustration about turbo lag and rev hang, @Belthasar. I recently drove a buddy's old beater Toyota Matrix with a 5-speed and was reminded about the good old days of normally aspirated engines and a manual. The Matrix isn't exactly lustworthy, but the drivetrain is satisfying to operate. I've found that new engine/trans/dogbone mounts have improved shifting (and especially rev-matching downshifts) and responsiveness in the GSW.

 

[Diggs24]

Yup, either bad actuator or corrosion.