Wastegate issues...i think

[Spy_91]

So I decided to blow some of the cobwebs out of my mk3 the other day and right before I shifted to 3rd (around 5600-5700rpm and pushing 9 psi, fyi...i have a stock turbo and my EVC was set to override the OEM settings) the engine cut out/stopped boosting, but the car did not die and the check engine light came on momentarily. It felt like i over boosted and the car shut down to keep the engine from "exploding"?

The only things i noticed are that there is no longer the wastegate flutter when i shift/let off throttle. And after i shift there seems to be more turbo lag than usual. It is boosting though, cause the needle does go over 0 psi and i can hear it. It also doesn't seem to pull like it used to. I have spent several hours tinkering with the actuator, o2 sensor, bov, etc. really trying to avoid taking the turbo and/or down pipe off and really want to avoid taking it to a shop. I also reset the EVC (HKS evc III) which was probably a bad idea since the car wasn't boosting properly?

I know next to nothing about this stuff and i looked at similar forums on here but i couldn't find any solutions. Any suggestions would be appreciated

[cre]

FYI, EVC is a model, EBC is the type of device: Electronic Boost Controller... May prevent confusion to refer to it as an EBC or give the full name of the device.

The flutter when shifting is compressor surge; It's indicative of a bad BOV/BPV or (if it's an aftermarket and if adjustable) an improperly tuned BOV/BPV. Unless your wastegate is frozen in the open position everything sounds more like a bad BOV/BPV. You may have blown an intake coupler too.

Typically when the wastegate goes it fails to open causing you to build more and more boost as the engine load increases. You would have hit up to 12psi before you hit fuel cut.

Remove the EBC from the wastegate's vacuum line until you have this sorted out, then put it back and get it retuned.

Check for diagnostic codes too, you've probably got codes for airflow or abnormal turbo pressure stored; See the MKIII FAQ section for info on how to do this.

[Spy_91]

Thanks for the clarification on the boost controller and for your thoughts.

The bov on there is stock, most likely original.So start with a new bov? And if that doesn't fix it then you think the wastegate failed and its stuck open? Is that fixable or would i need a whole new turbo? One of my original thoughts was that the wastegate actuator spring failed....does that sound like a possibility?

I dont think its an intake coupler. That was something i checked when i was tinkering with the intake....didn't find anything noticeably wrong and everything was snug and secured.

I could have hit 12 psi...i just remember it being at 9 the last time i glanced at the gauge.

Thanks again!

[cre]

Error codes?

If it's mostly stock and you're not planning on going beyond 10 to 12psi I'd locate a Bosch BOV... I can't remember the model # but it's been posted here a few times so you should be able to find it by searching.

Yes, a wastegate actuator with a shot spring would do it, but that's very uncommon. Typically the rubber diaphragm goes long before the spring will. Seized wastegates can often be repaired or you could get it welded shut and add an external wastegate. Personally, I'd try to free it back up and if that fails then I'd get the whole thing rebuilt and upgraded. Hook a bicycle pump to the actuator; Disconnect the actuator's linkage from the wastegate's arm; and pump a couple times, the arm should move 1/2" to 1" (You may try testing the BOV the same way). Don't exceed 15psi or so.

A wastegate that's stuck open really shouldn't cause any diagnostic codes to be set as far as I can reason... On the 7M-GTE the ECU judges boost pressure based on air flow readings, it doesn't see any reference to manifold pressure so it's most likely to just assume that the airflow is low at your given RPM because you're driving at a low load and thus not boosting (ie: driving down hill).

[Spy_91]

I haven't had much time to work on the car cause i'm trying to finish our house. Nevertheless, i finally got around to installing the new BPV (Bosch #0 280 142 110) and reset my EBC using the self learn mode. I could blow thru the original BPV so it was bad. The car boosts better now, but there is a woot or hoot sound at high boost levels and there is a lag around the same time of the woot sound. It didn't make this sound before. Is that normal? I bought new hoses that reduce from 1" to 3/4" so everything fits properly. I've read other threads that say the wooting noise is common with improperly adjusted BOV/BPV. But the bosch isn't adjustable....

Really hope i didn't buy a defective BPV. I couldn't blow any air thru the new bosch BPV so I assume its working properly. Anyone else have this wooot sound with their bosch?

The error code is 34 - abnormal boost pressure. I dont think i hit the 12 psi fuel cut, I think the abnormal boost pressure caused the car to shut down and the check engine light to come on, and i mistook it for "fuel cut." This happens every time I set the EBC to override OEM settings... around 5-6 psi at wide open throttle the car shuts down. Would an improperly tuned EBC cause this?

I still need to check the wastegate actuator with the bicycle pump and see if it functions properly. I will post what i find.

[Green7mgte]

id check for boost leaks.. shouldn't hear any whoosh.

[Spy_91]

I have gone over the intake hoses so many times and everything is tight and secure. Any thoughts where i could look that isn't obvious?

Its not a whoosh.....its definitely a woooot sound. I used to have the flutter sound like ch ch ch ch sssshhh, but not anymore.

[pandrade]

from a bosch bov upgrade i read about on the faq's they where saying u would hear that whoo noise occasonaly but i have never done this mod( still on my factory bov at 135k miles, surprisingly it works perfectly)

[cre]

Originally Posted by Spy_91

I've read other threads that say the wooting noise is common with improperly adjusted BOV/BPV.

Where? This isn't accurate... at least not for the situation I think you're describing.

Originally Posted by Spy_91

Its not a whoosh.....its definitely a woooot sound. I used to have the flutter sound like ch ch ch ch sssshhh, but not anymore.

Ok, flutter = b a d. I'd need more specifics to really give any opinion on the "woot" you're hearing. The discharge sound will vary depending upon the configuration of the vehicle's intake. The Bosch sounds much like the stock BPV but as you didn't have a good one to start with it's a moot point. If you have a large, open element air filter you'll have a louder "woosh" kind of sound. Check your vacuum tubing to be sure there aren't leaks which may be causing the BPV to open slow or just partially.

There should be no sound WHILE you are boosting. If there is the most common causes (as well as causes of the code 34) are: #1 boost leak, #2 bad AFM, #3 shot wastegate and #4 bad turbo.

An improperly setup EBC shouldn't really affect the vehicle as you are describing but anything's possible. A wiring problem would be more likely. Personally, I'd remove the unit until everything else is fixed.

[Spy_91]

Where? This isn't accurate... at least not for the situation I think you're describing.

So woooting sound during boost = not good. I dont remember where i read that, but it wasn't on this forum. I just googled "bypass valve wooting sound" Just goes to show you can't trust everything you read on the internet

Ok, flutter = b a d. I'd need more specifics to really give any opinion on the "woot" you're hearing. The discharge sound will vary depending upon the configuration of the vehicle's intake. The Bosch sounds much like the stock BPV but as you didn't have a good one to start with it's a moot point. If you have a large, open element air filter you'll have a louder "woosh" kind of sound.

The woot/hoot sound happens at WOT around 4-6 psi. It doesn't woot when i let off the throttle to shift, that makes the whoosh sound you talked about. And btw i have the hks mushroom head air fliter

There should be no sound WHILE you are boosting

Except for the hissing of the turbo

bad AFM

I replaced the AFM like 3 years ago, really hope its not busted already. The car runs fine (with the recent Bosch BPV mod) and idles prefectly at like 600-700 its only when you punch it that it has issues boosting. When the AFM went bad the first time i couldn't drive it at all....it would just stall and get bogged down.

Personally, I'd remove the unit until everything else is fixed.

Yeah....I hooked it back up after i got the BPV on there and then after the car started shutting down while boosting and having the code 34 so I disconnected it again.

I really appreciate all the posts. Sounds more and more like I have an elusive boost leak somewhere. I'll recheck all the lines and the WG actuator and keep ya posted. Thanks again!