I'd say take the tune out and then see how the car runs just with the GMTU. If you're getting full boost one second and just 10lbs the next second it might be a calibration issue.

 

I thought about that too and got ahold of Vince about it-
He said if there were any issues with the program....it would have started from the get go. It wouldn't have last 2 months then went crazy...

 

cleaned the lower MAP sensor....

Thought maybe it was a little dirty...but no change in how it runs...
Waiting on the upper IC pipe to get here. It's the only thing left it sounds.

 

may have a boost leak.....the new pipe will help eliminate that or it could be the cold side pipe. do a boost leak test and eliminate that possibility

 

cool man, I can probably get most of the materials at Lowes to make a boost leak tester cant I?

 

yeap. just get a 2.5" pvc cap and put it on a 6" long (or so) piece of pvc pipe and drill out a hole in the cap and install a valve stem in there....seal it all up and you are good to go.

see post 15 for how to boost leak test if you don't know. if you want to do option 1 then just add a 2.5"coupler and a couple clamps to the end of the pvc pipe.

https://www.chevyhhr.net/forums/show...t=38068&page=2

 

so...this is pretty much how you do it correct? Just undo the Hot Side Pipe, install the leak tester in the hotside pipe and pressure it up?


http://www.cobaltss.net/forums/08-10...ss-lnf-223319/

 

yeap....and i believe i listed the wrong size pvc pipe....think his is correct so go by that. i forgot the stock coupler is reduced from the piping size.

 

Just did a boost leak test...and wow....it really really worked great! Cost me about $13.00.

Anyhow....it won't hold PSI for long (I installed a gauge telling me the exact pressure in the system). I have a pretty good leak on the hotside of the IC pipe....where it's "put together" from rubber to plastic. I don't think I can tighten anything can I? (if not, no big deal, I have a ZZP HotSide Pipe on it's way)

Also...would a leak like that cause it to run that bad? (according to the boost in the video's I posted)

I'll post a couple video's in a sec of where it's leaking.

 

http://www.youtube.com/watch?v=EmNaRSxdLaQ


It's pretty much leaking all the way around where the rubber and the plastic hotside pipe meet. If you move the piping....it effects the PSI as well..