[RacerZook]

2017 with ~25k miles and I was getting on the freeway when it felt like the engine power was cutting in and out. ALmost like boost was fluttering (best way I can describe it). Got out of the throttle and it smoothed out, but immediatly got a CEL. Car was driving fine, so babied it the short drive home. Checked the CEL and it showed P0299 for low boost condition.

Cleared the CEL and went for a drive to see if it would come back. Couldnt recreate the event or the CEL, but the car is noticably slower to respond, seems like it takes much longer to build boost and power. Took it to the dealership to diagnois, and they said it was fine, measure peak boost at ~34psi so doesn't seem to be leaking.

Only had the car for about 8 months so still learning the mechanics, but from what I've learned is that boost/wastegate solenoid (seems like the same part goes by different names?) could be to blame.

Would it be possible that instead of the solenoid not allowing full boost, could it be reacting slowly? So it still allows full boost, as the dealership measured, but just taking twice as long? Also, any tips on how to replace it would be appreciated as well! Thanks!

 

[morbid]

Also check your intake piping. I had blown my hot-side pipe off the turbo and it was doing that. It could be any of the piping between the turbo and intake manifold that has come loose, or as someone experienced a few months ago, the flexible parts could have torn.

EDIT: oops, nevermind... apparently I missed that 2nd paragraph.

 

[mikesk]

Your ecu was retarding timing for conditions preventing what your calibration would allow. Could be any combination of poor spark, additional load, higher IAT or reduced octane due to bad fuel or oil mist thru the PCV. I'd guess quality of fuel from the pump, try adding octane booster to see if it resolves it.

 

[RacerZook]

Mikesk-Gas is fine, same issue even after adding gas. Interesting to think its retarding the timing, but don't think it would cause a low boost condition?

 

[320icar]

it to the dealership to diagnois, and they said it was fine, measure peak boost at ~34psi so doesn't seem to be leaking.

Excuse me? That should be a big red flag for trusting your dealership right there. Do you have a massive built motor? Stock is what, 15psi normal, 22psi on overboost? I run peak of 28psi, with the average being 24-26psi to redline, and that’s heavily tuned with water/meth.

 

[RacerZook]

Excuse me? That should be a big red flag for trusting your dealership right there. Do you have a massive built motor? Stock is what, 15psi normal, 22psi on overboost? I run peak of 28psi, with the average being 24-26psi to redline, and that’s heavily tuned with water/meth.

Well that's definitely interesting. The dealership experience was less than confidence inspiring, to say the least.

From their notes "turbo boost pressure desired highest was 34.9psi and actual was 36.16 psi. Turbocharger is actually working better than the computer is commanding".

I'm still learning about this car and wish I knew what psi was normal for a stock car. I sure would of made a bigger deal out of it than I already did!

So my question is now, is it physically possible for the stock turbo to reach ~35 psi? Is the dealership just full of it?
Or is something else hindering the performance where the ecu is asking for that much boost to compensate to hit the power target?

Thanks

 

[RacerZook]

Actually, thinking about it now, I bet their measurement is absolute pressure and not gauge pressure. Subtract 14.7 psi from their measurements and things look more in line.

 

[Pezzar]

If the boost control solenoid is not operating then the boost will likely be restricted to spring pressure which is about 12psi which would make the car seem slow

It’s mounted on side of the engine (timing chain end), remove it and test it. Put a current across the solenoid and you should hear it operating and should be able to blow air through when powered up and opened

 

[TailStrike]

2017 with ~25k miles and I was getting on the freeway when it felt like the engine power was cutting in and out. ALmost like boost was fluttering (best way I can describe it). Got out of the throttle and it smoothed out, but immediatly got a CEL. Car was driving fine, so babied it the short drive home. Checked the CEL and it showed P0299 for low boost condition.

Cleared the CEL and went for a drive to see if it would come back. Couldnt recreate the event or the CEL, but the car is noticably slower to respond, seems like it takes much longer to build boost and power. Took it to the dealership to diagnois, and they said it was fine, measure peak boost at ~34psi so doesn't seem to be leaking.

Only had the car for about 8 months so still learning the mechanics, but from what I've learned is that boost/wastegate solenoid (seems like the same part goes by different names?) could be to blame.

Would it be possible that instead of the solenoid not allowing full boost, could it be reacting slowly? So it still allows full boost, as the dealership measured, but just taking twice as long? Also, any tips on how to replace it would be appreciated as well! Thanks!

Theres no way boost should be 34. Max is near 24 on these engines. Possibly a clerical error but that makes me doubt the diagnosis. I would have the intake smoked before I put a bypass valve in it.

 

[axelr]

psia, subtract 14.7?

Beside that the low boost error comes after a long time (several seconds) being well below expectations for the given throttle demand. The CEL came for a reason.

Check the electrical connection to the wastegate solenoid. If you pull up the coolant expansion tank and move it out of the way you’ll see everything clearly: it’s on the front-left of the engine below the exhaust camshaft sprocket (the engine front being where the timing chain cover is, looking transversally.)

 

[Pezzar]

Hence why I advised op to pull the solenoid and test it

 

[NBcfl]

Hello, does anyone know a p/n for the correct bcs? very hard to find

 

[axelr]

Hello, does anyone know a p/n for the correct bcs? very hard to find

 

[NBcfl]

Ok I appreciate it @axelr Ordered from Amazon most of the numbers seem to line up except for couple at the end. Hopefully it works. Amazon.com: Pressure Control Valve Sensor OEM 31219138 70222100 For V-olvo S60 S80 V60 V70 XC60 XC70 : Automotive

 

[axelr]

Ok I appreciate it @axelr Ordered from Amazon most of the numbers seem to line up except for couple at the end. Hopefully it works. Amazon.com: Pressure Control Valve Sensor OEM 31219138 70222100 For V-olvo S60 S80 V60 V70 XC60 XC70 : Automotive

You are welcome. The OE ones in our cars are made by Pierburg in Germany:

Note the tiny barbs on the input (the side with the metallic pipe) that comes from the compressor.

On the RS they used a bit of thermo-retractable sleeve to secure that connection. When you undo it it’s a bit destructive and it won’t hook well to the next valve. You have to pay great attention to that connection and make sure it’s secure and air-tight at 2+ bar.

The second important one is the beige perpendicular output that goes to the capsule. If either fails or leaks the turbo will overboost.

 

[Jawknee21]

Ok I appreciate it @axelr Ordered from Amazon most of the numbers seem to line up except for couple at the end. Hopefully it works. Amazon.com: Pressure Control Valve Sensor OEM 31219138 70222100 For V-olvo S60 S80 V60 V70 XC60 XC70 : Automotive

Did this fix your problem?

 

[Jawknee21]

2017 with ~25k miles and I was getting on the freeway when it felt like the engine power was cutting in and out. ALmost like boost was fluttering (best way I can describe it). Got out of the throttle and it smoothed out, but immediatly got a CEL. Car was driving fine, so babied it the short drive home. Checked the CEL and it showed P0299 for low boost condition.

Cleared the CEL and went for a drive to see if it would come back. Couldnt recreate the event or the CEL, but the car is noticably slower to respond, seems like it takes much longer to build boost and power. Took it to the dealership to diagnois, and they said it was fine, measure peak boost at ~34psi so doesn't seem to be leaking.

Only had the car for about 8 months so still learning the mechanics, but from what I've learned is that boost/wastegate solenoid (seems like the same part goes by different names?) could be to blame.

Would it be possible that instead of the solenoid not allowing full boost, could it be reacting slowly? So it still allows full boost, as the dealership measured, but just taking twice as long? Also, any tips on how to replace it would be appreciated as well! Thanks!

How did you fix your problem?