So over the last few days I noticed while driving in town that the car felt unresponsive and overall didn't feel right. Instead of making it long-winded, here's the symptoms:

• Under normal load conditions (ie. daily driving) the car feels sluggish, unresponsive and more throttle input is required to accelerate. Just to get going in traffic I need to give it 50% throttle, even 1st feels "wrong".
• WOT in 2nd I get 0 boost. It hovers at 0, tries to bump above and will not. Motor sounds like it's running like absolute ****, exhaust note changes, I feel like I have less power than a flippin' moped (not exaggerating here). Needle on the boost gauge wavers doesn't sit perfectly still. Building even general pressure takes far longer than usual.
• WOT in 3rd, same as 2nd gear
• WOT in 4th (lower RPM) I got some boost, but very little. Less power than I'd expect (ie. clutch didn't slip,sounds a LITTLE better than 2nd/3rd)
• Listened for a boost leak and think I might hear one but it's tough to say because it seems sometimes I hear the turbo, others I don't.

Reading on here I am going to suggest the dealer inspect the Evap Purge Solenoid and look for boost leaks. I'm suspicious of a vaccuum leak more than a boost leak but it's tough to say for sure. It appears to show up only when it's warmer since yesterday and this morning, boosted fine no problems. Warmed up by end of day (sat outside at work all day), start it, hear turbo in 2nd once and then could feel it happen. Complete loss of power, turbo doesn't sound like it's spooling at all (though I hear a noise occasionally which is why I'm considering a boost leak) and overall sucks and is dangerous in traffic imo.

Besides looking at the two items above any other suggestions? I've considered the wastegate solenoid and BPV but there isn't a CEL and I don't have a means of scanning for a code (in case one exists) until it goes in tomorrow (which is a 30 minute drive so hopefully it's a simple fix or it will be a painful/dangerous drive home...)

 

I think a SEVIERLY dirty airfilter can give you those symptons. Or some other air obstruction.

Best Bet: Check for codes
You might have a boost leak ,or
something wrong with your SC.

 

There is no CEL, that means the correlation of air going past the maf and what the engine is sucking in is relatively the same, otherwise it would set a code.

based on that assumption, you have a couple things it could be. Firstly, your MAF sensor itself, it could be dirty, particularly if your running a non-dry filter. Second, the classic sign, an improperly wired TMAP sensor in your charge piping as a result of your stage kit installation. Finally, it's certainly possible to have a torn BPV diaphragm. This doesn't ALWAYS throw a code, but normally it will.

The not so possibles includes aerated fuel (it happens) bad PCM (mine has been replaced due to reference voltage being out of tolerance, which is COMMON on E67 ECUs), cracked intercooler end tank, bad turbocharger...and I'll stop there. Let me know what comes of it.

 

that is exactly what my car did when I had a busted intercooler (hit a cat at 65 ftl) but had instant cel so IDK if you dont have a code

 

I'm going to have them do oil/filter while it's in so they should check it again. Last it was in (different dealer) they indicated it should be good for another 10,000km (uh 6500 miles...I think). I haven't checked it recently, perhaps I should...I'd assume though if it were that filthy it wouldn't matter what outdoor conditions it's seeing. IF there's not a code set that isn't causing a CEL I'm fearing the worst case (long drawn-out diagnosis ).

Awesome, thanks a lot! I'll be sure to update the thread with what the dealership finds, etc. I'm hoping it's simple and not an on-going thing .

Question, could a loose TMAP cause the same, or leakage of liquid into the heatshrink (mine's soldered, heatshrink, electrical taped)? It was installed last November so it has been installed for a while. I tried rocking it and it felt solid, but it's also a PITA to get to.

Well a cat at 65 would leave a bit of a dent I'm thinkin . If I have a pinhole, just enough to leak air but not enough to completely throw the TMAP/MAP off (odd this hasn't happened when it isn't boostin?) then I could see it so I haven't completely ruled it out as a possibility . Odd thing is it came out of nowhere. No highway, no flying debris, etc.

Thanks for the input!

 

Dropped her off this morning. They've had a couple in with similar issues already so they know where to begin looking. That's a bonus !! Also going to check the oil leak and order the parts (finally after I procrastinated) for the TSB since I should likely get it done.

 

Issue was diagnosed in a couple hours. A code had been set but no CEL was displayed (obnoxious), forget the code but it's well known turbo performance code. Pressure testing the system showed I was inflicted by the infamous "GM put bolts too long around the lower charge piping which can eventually result in a puncture because they touch the charge piping and are very sharp" TSB .

There is a small pinhole in my cold-side charge piping near the IC resulting in a horrendous boost leak when the piping heats up and expands (which explains why it is find in the morning, it has been cold lately). Parts are ordered and I requested the simply seal off the hole temporarily (instead of providing a free rental) and I'll behave myself and try (keyword try) to stay out of boost .

They confirmed there are no other leaks in the system, MAP and TMAP are properly seated, the oil leak is miniscule (TSB) but cleaned it up and put dye in the system to determine how much is leaking and will check it when the car goes back. They also changed the air filter at my request since it had a fair number of KM on it and the intake system was torn apart anyways.

Guess I'll see how well the seal-up job holds (temporarily sealed with silicone) and hopefully she runs good as new until the parts arrive late next week .

 

Another update on this one. Started the car in my garage this morning and I heard what I believe was compressor surge. Adding that to my list of things to check once the new cold-side piping is installed. I'm hoping it's just a result of the temporary patch job having some small air leaks in it leading to some slightly skewed readings between MAF and MAP!

I'll update the thread again once my parts are in/on, or if anything else acts up in the process.

 

Sounds just like my car did with my busted intercooler endtank.

 

Then they're definitely on the right track . The idea is to get the new cold-side charge piping on, shorten the support bolts, then recheck the system once it's on to make sure nothing else is leaking/malfunctioning . My friend had the exact same problems, cold-side charge, IC and I think the hot-side was starting to rub through as well so they replace it before it ruptured.

 

The SS/TC has had problems with the stock charge piping coming undone and creating huge boost leaks. It could also be possible your boost bypass is jammed open.

 

Well, still waiting on the part so I called to check up on it. Turns out it's coming from the manufacturer (in other words GM isn't stocking them anymore) so "in transit in US" meant "from manufacturer -> GM". Expected to arrive here middle of next week so by that time it has taken GM 3 and some weeks to get me a part which results in a major driveability issue (the seal is starting to leak slightly again). The dealer requested a rush delivery but GM failed to mention "oh ya we need to get some made first"

Morale of story:

This happens again I'm buying aftermarket this is unacceptable ! GM should have informed the dealer this was the case immediately not just let it drag on with them following up daily and finally indicate this was the case.