p2261? Bad Bypass?

[2o6]

Hiya, I’ve got a 12’ LTZ 6MT Turbo car.

CEL popped on for P2261, which I suspect is the bad diverter valve. I don’t have any drivability issues. It runs fine, although I suspect that boost is slightly lumpier than normal.


I tried searching, but the forums all have the bypass the bypass mod, or the BNR atmospheric bypass valve mod, which require a tune.

The cheapo AC DELCO one is like $23 from rock auto. Is there anything I should know? Is this a hard job? Is this a complicated job? Will I be ruining my car driving it until the part gets in?

 

[Pirate Luke]

To clarify, you DON'T have the bypass the bypass mod?

That bypass valve allows the computer to control the boost applied by the turbo in order to protect it from extreme conditions/pressures. I wouldn't recommend bypassing/driving it long without it. There's a good reason engineers put it there.

Unless you're familiar with the underside of the intake manifold and have tiny hands, you'll have to remove it to access that valve/tubing. It's not hard at all, here's a guide to remove our exact manifold.
How-To: Remove 2011-2016 Cruze 1.4L Intake Manifold

 

[Maddmatts]

That bypass valve allows the computer to control the boost applied by the turbo in order to protect it from extreme conditions/pressures. I wouldn't recommend bypassing/driving it long without it.

The bypass the bypass mod intends for the recirculation valve to continue functioning as a safety device. It's just no longer pulling double-duty to dampen the feedback loop typical of turbocharged engines, which is considered by many to be one of the fun aspects of having one. The system's not there for reliability. It's there only because the average driver is uncomfortable with that sensation.

I agree with checking the vacuum lines between the intake manifold and the recirc. valve on the turbo. I recall someone discovered one of the tubes had popped off somewhere and caused that code before. Use a flashlight and an inspection mirror if you don't want to remove the manifold.

 

[Pirate Luke]

Thanks for the clarification. I'll have to look into understanding it a bit more. I was under the impression the bypass mod could have some negative side effects on the turbo at WOT.


*EDIT*
So, I spent a good amount of time going over the entire thread here (http://www.sonicownersforum.com/forum/morgan-performance-fabrication/10742-bypassing-bypass-valve-solenoid.html) and also reading about ECU controlled BPV/BOV solenoids. Very interesting stuff! I will retract my statement about not recommending it, seeing as many have positive change and it's easy enough to reverse. In fact, I may try it myself.

Interestingly, I now have a couple more reasons I believe it was put there to begin with. That's a discussion for a different thread though. Thanks again Maddmatts.

 

[2o6]

The bypass the bypass mod intends for the recirculation valve to continue functioning as a safety device. It's just no longer pulling double-duty to dampen the feedback loop typical of turbocharged engines, which is considered by many to be one of the fun aspects of having one. The system's not there for reliability. It's there only because the average driver is uncomfortable with that sensation.

I agree with checking the vacuum lines between the intake manifold and the recirc. valve on the turbo. I recall someone discovered one of the tubes had popped off somewhere and caused that code before. Use a flashlight and an inspection mirror if you don't want to remove the manifold.

So am I ok to drive? I’m not sure if this valve is just to smooth out boost peaks, or whether or not my car is gonna blow up if I drive it to work.

 

[Maddmatts]

The primary purpose of that valve is to prevent the turbo from overpressurizing the pipes and intercooler when the throttleplate suddenly closes. The danger can be largely mitigated by easing off the throttle after moderate/heavy acceleration rather than lifting your foot completely off the gas pedal.

What I can't guarantee is that other commuters won't deny you the chance to do this.

If you feel the valve itself has to be replaced, put aside a good deal of time for it as I hear it's a real PITA to reassemble it. Also make sure to have an assortment of socket extensions available.

 

[2o6]

Alright, I had my mechanic put it back together, with a new AC DELCO Bypass.


Cleared the code. Came back after roughly 80-100 miles. It’s done it twice now. What else should I be checking?

 

[Pirate Luke]

For some reason I initially thought you were referring to the BPV solenoid. In any case, if your mechanic replaced the Bypass Valve seen here (built into our turbo):

Then the next easiest thing to check IS the BPV solenoid and its connecting tubes. The BPV on the turbo connects to the white cap on the BPV solenoid as seen in the picture below:

I'd make sure those tubes are all hooked up correctly and verify the BPV solenoid is functioning correctly. If you follow Maddmatts tip with the flashlight and mirror, this solenoid is under the left side of the intake manifold if looking at the engine bay.

 

[2o6]

Wait wait wait.

Hold up;

I bought the plastic thingy; which I guess is the BPV
solenoid. So the whole bypass valve is different? Where is that part number? If that’s the case, rock auto only gives the code for the solenoid.


EDIT:

Yeah, I definitely bought the BPV Solenoid. So, My BPV is likely still broken. I know BNR sells an aftermarket one, but is there any way to get a stock one? I can't for the life of me find the part number.

 

[2o6]

Aaand, I answered my own question. Looks like the BPV is sold as one unit as a whole new turbo. Which is bull; the thing is plastic and held on with torx bits.



I just ordered the recirculating one from BNR. Hopefully I get it before the weekend. UGH.

 

[Pirate Luke]

Honestly, I feel a little better for you knowing this now. Haha. Most of the threads on this issue that have BPV replacement without resolution end up needing the whole turbo replaced. I actually have the forge BPV and can say it's 10x better than the stock rubber piece. It holds boost better (for me) and is of better quality.

Knowing that your solenoid is new and your BPV is about to be replaced with a better alternative (BNR), please let us know the outcome. It's how we learn.

Also, for what it's worth, my philosophy has been when it breaks replace with BNR product. Lol. Now just waiting for that stock turbo to fail. :banana:

 

[2o6]

I think it should probably be fine. I didn't have any under-boost codes, no drivability issues, and the whole car had the same MPG. I think if the turbo were ruined, I'd have a host of issues.

So yeah, I never actually replaced the BPV. Just the solenoid.

 

[2o6]

oookay. BNR valve installed, and now i'm getting P0299! (In pending). P2261 was still stored, so I cleared it out. Initially, after install P2261 wasn't pending. Then later it was. I decided to clear it out, and to a hard accelerate, and then P0299 showed up in pending, not even 15 miles after.


I'm asking my mechanic to see if he installed it correctly and a seal wasn't forgotten or slipped off. I hear a weird "woosh" from the site of install, but I can't tell if my mind is just playing tricks on me.

 

[2o6]

I think it’s solved now!

There was a line from the intake to the BPV that popped off.


Now I wonder if this was the case from day one...


Oh well.

 

[Pirate Luke]

Ahh well at least all is good now. That Forge BPV should last much longer than the stock one anyway, so money well spent regardless IMO.