alright guys, I have had my gmas1 for a little bit over a year, i then put on the KN SRI and Injen CP the next day. i recently just put on my MPX catted DP with cat back 3 weeks ago (800 miles)....so heres my dilema. me and the lady went out to eat 60 miles away, ss was boosting just fine on the interstate at 80mph, all the way through town, stopped at a store, got back in, drove off and it was fine, then we went to eat, got back in and all of a suddden flutter, WTF? so luckily there was a menards right by so i drove realllllllly slow to prevent boost/flutter, went in and grabed a allen wrench set to remove the negative cable on my battery ( aftermarket batter) waited 15-20 minutes and flutter was gone, drove home 60 miles just fine. i shut it on and off a number of times and continued to be fine. i figured hey, maybe the car got mad and needed to be reset to "learn" the less restriction due to my DP. got up this morning and on the way to church, FLUTTER!?

so i put the car on my lift and am now driving my truck, been reading all these threads and i really dont think its a mechanical issue like boost leak or anything, i will look tomorrow. but what i do think it is, is a dirty sensor like many of these threads have stated. i have never cleaned my sensor after installing the KN SRI and it has been on for 10K+ miles. so im leading towards looking over the sensors, checking my stock cold side piping comming off my intercooler because many of you have said it can crack or become loose, and i will also check the MAP sensors the dealership in town put on. (i dont know where they are located tho so i would like some helpful tips on what to look for and what im checking cuz i never really investigated as to where they were:/ )

so after all that bablying, sorry, but i would just like some great opions for what to check tomorrow when im off work. also would the forge BPV or a turbo timer be nice to consider? maybe seafoam the gas tank? i just really think its electronic that needs to be cleaned or something. cuz like i said i pulled the battery and it was fine. thank you guys!!

 

also, was not beating on the car at all. no higher then 4k rpm before either start of flutter. it never started mid drive, each time was fine, until i shut the car off and started again, that is when the flutter started..

so far no CEL either.

 

anybody? willing to listen to all advice. please!

 

Turbo timer isn't needed, our turbos are water and oil cooled. Just don't beat on it for a while and shut it off immediately. I would boost leak, check your stock bpv, and maybe remove the vacuum tank (or just test without the vacuum tank connected, there a few threads around)

 

Bypass the vacuum tank and test. Then remove the bpv and inspect it.

 

ok, i understand the functions of a turbo set up, but no idea what the vacuum tank is and where it is located:/, by bypass do you mean just disconnect and connect the two hoses together?

both of you said mechanical issues, which im not doubting you at all, i will check those when i get more free time, however, i pulled the battery and then it worked. if it was a mecahnical failure wouldnt it stop working indeffinitley? some of the guys on here were saying MAF or somethign about the sensor on the cold side piping (where is that??) being clogged with dirt and had to be cleaned.

 

There is a vacuum tank under the intake manifold. We bypass it by doing the following:
Refer to post 31 I posted. If this seems too difficult then I would really suggest a dealer visit. As you may not have the knowledge you need to fix this.

Sorry for the major link fail. LOL. This is an easy thing to do OP, but I seriously doubt it will correct your problem.

https://www.cobaltss.net/forums/2-0l...68/index2.html

 

^ wrong link.

 

https://www.cobaltss.net/forums/2-0l...68/index2.html

Right link. Post 31.

 

I'm an hvac technician! nothings to difficult till your ***** deep in a furnace trying to hold seven things and tighten a hose clamp with one hand haha. but ok, I ran to the shop and found some vac hose, by passed it, I did reset my battery just so limp mode went away, and I drove around a little bit last night and so far no limp mode/flutter. however on start up I had 2 missfires, after the cat warm up was done it was fine.. I drove around and things were good, I floord it just a Lil in second and got up to 21psi right away (I will redline it tonight to see what I get) it seems to boost quicker, but the bpv does sound a little different. is bypassing that tank ok for the car?


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I broke my vac tank a week or two ago while trying to bypass it. So I just unbolted it up and removed it all together. Car works fine. Other then my major issue with my fuel trims and cold start stalling. Which Im sure are unrealated to the removal of the vac tank. From what I have read it does not harm anything to totally remove it.

 

I've had mine bypassed for over a month now and have had no issues. the Sky Redline and Solstice do not come with the tank and they were the original LNFs

 

Yes bypassing is ok for the car. Now take the tank out completely? I'm sure the check valve or tank itself is busted. I don't believe in plastic parts on an engine, unless they are the obvious clips and small stuff. Whoever came up with the idea of making plastic engine parts like vac tanks, piping, intercooling or manifolds should be put in jail

 

Lol, well engineers have design standards like anything else. And a boss that is telling them to keep costs down.

You want a budget turbo 4 cylinder, you are gonna get a budget turbo 4 cylinder.

 

Costs, hell. Keep the weight down. If the plastic tank and the plastic headlight tray and the plastic everything else were metal the car would weight 700 pounds more, handle like crap, and get terrible mileage.

and would rust.

I'm perfectly fine with plastic, thanks.

 

True, the only part they really screwed up was the shitty end tanks on the intercooler. Beside that everything else seems to have a normal failure rate.

 

so can you explain the missfires? if everyone is 100% sure it's good to go ill remove it. I seen someone dynoed the removal and gained, is this true? I felt like the car spooled faster honestly...

another thing, why did the bpv sound different? it use to be a high pitch sound now it's much lower pitch and at one point I thought it was flutter but it was the sound of the valve



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would the forge bpv be worth buying? does any one have issues with this? should I leave my tank by passed if I get it?


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The forge unit is a nice replacement and will probably last longer, but if the stock one is good and unless it's messed up there is really no need.

I have had my tank bypassed for 3 years. No issues. I'd just leave it bypassed

 

The forge unit is serviceable. The factory one isn't. I service mine once every 6 months or it starts to stick.

 

by sticking do you mean not entirely opening or what? I will buy it and gladly service it Cuz I'm really scared to even drive my car now after that fluttering I had the other night. I just want to fully get rid of every junk part on this car from the factory


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Pretty sure some screwed up their calcs on the endtanks, or the plastics company messed the plastic resin up in a few batches.

 

Or someone forgot a pothole test.

 

I have the Forge VTA BPV and i love it. i had to lube it up some with Mobil 1 grease cause it was getting stuck.

 

I found that if I let it go too long without service the piston will stick up and not come back down. Then there was the one time where after I serviced it I didn't screw the cap on fully and that extra clearance let the piston go back so far that the O-ring hopped out of the barrel and hung the piston. That one was my fault though. Failure to fully pay attention to detail.

If I service it at proper intervals and put it back together right it is trouble free. I've had it 30 thousand miles.