Turbo DTC set....need advice....
 

Firat of all, I would like to thank Brad (ChevyMgr) for posting the DTC's as I set a check engine light on the way home tonight, and did get the following code.....P2261 Turbocharger Bypass Valve Stuck Closed

I have noticed recently that there have been times when I lost the "boost" while driving, and after I would come to a complete stop, and then accelerate, the "boost" would return. This happened twice in the last week, and finally set the above code.
So I need to know (since I am still not experienced in "turbos"), would this mean that the Dejon BOV spring that I installed a while back might have to much tension, therefore holding the valve closed on occassion? Or am I off base here? Would I need to remove the spring and then reinstall?
What procedures should I follow? Or what do I need to do to correct the problem?
Any insight is appreciated. As a side note, it is running good, but not quite like before, I knew there was something off, but couldn't put my finger on it untill tonight when I got the code. thanks......Tom

AI would put the correct BOV spring back in there, then submit the car for warranty service.

thanks for the reply Mike, but I am out of warranty, although I remember someone saying that the turbo system is warranted for 100,000 miles. And I also have the BSR tune, even if I go back to stock and they detect it, then it's a no go for me. The more I think about it, it seems that there is something is preventing the door from opening, maybe the diaphragm got stuck, or is sticking on occassion, so I will take apart later today or tomorrow, to check it out further. Maybe someone else has had this experience and knows the fix, other than replacing the BOV, but if that is what it is, I guess I would have a choice to make!!!!

The bypass and BOV valves are 2 completely different animals.

The bypass is the internal electrically accuated valve attached to the turbo that regulates pressure going into the cylinders, open and closing (which vents into the exhaust), to maintain the proper pressure under the current driving conditions. This valve is monitored by sensors.

The BOV only vents the excessive boost pressure directly into the atmoshpere, when you take your foot off the accelerator, allowing for quicker deceleration. This is mechanical (spring and diaphragm) and is not monitored electrically.

This is my basic understanding of these valves, and info may be slightly off, but I hate when I tear apart stuff that has nothing to do with the problem to begin with.

Well I had the opposite thing happen as you, when I went to put my dejon spring in, my diaphragm was collapsed completely at 250 miles on the OD (along with the factory spring) and only released when I pried it apart to release the vacuum. I've had my dejon spring for roughly 2k miles now with no problems.

thank you for the above info....
see, I told you guys I still don't understand all of the workings of turbos:lol:
I wonder if the valve can go bad, or do the sensors go bad before the valvre does??? I guess since there are still times that I have boost, it would lead me to believe that the sensor(s) are bad. Now all I have to do is find out what sensors operate the valve and where they are located.....
ChevyMgr.....can you shed some light on this????

I was happy when I installed mine, it worked fine and probably still does, now that I know there is the BOV bypass and a BOV valve, it makes sense....

I rather do this myself if I can, so if anyone besides Brad (in case he hasn't read this yet) can supply me with part #'s and location, it will be greatly appreciated.....thanks...........Tom

I just had the same failure. Is this or is it not part of the emissions warranty? My car is stock except for the factory stage kit. Dealer wants to replace a cracked canister at a cost of $295. + $100 to clear the code earlier this month.

Where is the bulletin posted?

The dealer called and will knock off $100 now.

Yo Bob what canister?

Vacuum canister that operates the by-pass valve. GM says Not part of the emissions wrty

Have had many issues with the stock BOV. Dealer has replaced mine more than three times.

They are plastic crap and the diaphragm easily swallows the spring, etc. Stuck open/closed, etc. causing surging, overboost, etc. depending on when\where it sticks and what the engine is doing load or unload.

When tax return comes in, I will complete my order from FORGE motorsports to complete my signature.

This is no different than Mitsubishi cheaping out on Gen2 2.0 turbo eclipse vehicles (95-99 era Eclipse/Talons that shared the DSM engine platform). They were prone to failure or not holding boost. Many actually would salvage pick a Gen1 (90-94) and crush it for better performance or purchase aftermarket. It's a vital component that they shouldn't have "cheaped" out on.