Alright new to this forum and the Cobalt, but not to the auto industry...

My buddy's SS started having an issue recently. The turbo (when it decides it wants to) only spools up to about 3psi at WOT. He took it into the dealership prior to having me look at it. The tech wrote on the R/O: 'Charge pipe cracked, contacting the intercooler' (wtf?) They were going to charge him $350+ for parts and labor.

As far as I could see (2 hours of searching) I didn't see any cracks in ANY of the piping, nor did I see where it "contacted the intercooler" and could have possibly cracked.

Pulled the codes P0236 & P0237. I also checked the sensor on the cold side piping, and the MAP to compare the two. The MAP was dirty and had grease all over it, along with oil inside the manifold. The cold pipe sensor was clean. After reinstalling the sensors, he took it for a drive. It spooled happily to 21 pounds and pulled through second gear, heard a faint pop during shifting, and dropped off to 3 pounds again. And when the throttle snaps shut (between shifts) the turbo flutters (because it's obviously not spooling up). He did recently install a drop in K&N filter, which I know causes MAF issues from excess oil, but the MAF was clean.

Any suggestions? Thanks guys.

 

check the plastic end tanks on the intercooler. mine cracked the other day but i plastic welded it and it's holding

 

also the codes you stated are related to boost pressure I believe.

boost pressure sensors

 

Where can I find the boost sensors? Would a misreading cause the waste gate to open more than normal, therefore not allow full boost?

 

if you heard a pop your intercooler piping could of blown off or cracked etc. had this happen to me , i would just get a aftermarket hotside charge pipe and a aftermarket tredstone intercooler the stock ic has loads of plastic.

check down by the end tanks

 

He's stopping by again today. I'll report back here after I check the end tanks. It's weird that there are so many plastic 'toy' parts on a car that's doing 20+ psi...

 

ya really but it's also a mustang eater for 20 grand so you get what you pay for

 

P0236 is a boost sensor code. Boost leaks generally give a P0101. At least that's my personal experience. I have had some trouble with the P0236 code and it went away after changing the lower TMAP, the sensor in the cold side piping. It sounds like one of his MAP sensors is going bad to me. I'd take some other opinions too though before you go swapping stuff out. Though if it is one of the sensors, they are about $20 from CED, so not a huge deal.

 

If it's just oily sensors, you'll have to replace them and your buddy will need to get a catch-can. Does he have 3 bars installed with the GMS1 kit where the pigtails were soldered in?