21 psi

 

Hey jerrin, I was thinking that maybe the problem is in the solenoid........ because it happens when you are running at or very close to 0 kpa, the ecu can't decide if it should be bleeding off the boost, or letting it build so the solenoid is flashing from open/closed/open/closed trying to decide what to do with the BPV. when you are experiencing the "flutter" does it go away if you slightly increase or decrease throttle?? maybe the GMS1 tune has a slight bug in it, or the new MAP sensor is a little less acurate than the original stocker??? I dunno, just throwing ideas out there!

 

I'm gonna bypass the solenoid today to see if that helps. I'll keep these suggestions in mind as I'm working on it today

 

good luck! keep us posted on how it works out.

 

Well i bypassed the solenoid but it still did the same, just not as loud. I give up, I'm out of ideas. Have to wait till next Monday when I go to the dealer.

 

Let us know what the dealer says!

 

Yeah..... Gonna call them tomorrow to see if they can get me in sooner.

 

Ok..... My car is going to the dealer tomorrow after work and they are gonna look at it Thursday. If they can't figure it out, I'm going to put the stock chargepipes and stock intercooler back on to see if that resolves this issue.

Wish me luck!!!!

 

Luck!

 

I am experiencing the flutter with stock charge pipes! Just started about 2 weeks ago. All I have is K&N drop in, stock airbox, GMS1 tune and Hahn O/R DP. Its pissing me off. I thought my car was misfiring and then the techs at work said I would throw a CEL(I work at a Chevy Dealer). It happens in any gear when I'm in vacuum. Really annoying! Also it doesn't do it all the time, its sporadic.

Please let me know what you find out.

 

Same as mine.... Dealer said they can't find anything wrong.

 

not cool, there is def something wrong.

 

Strange. I get no surging with the stock or modded stage 1 tune and my mods.

Ripped BPV diaphram could cause it.

 

Well, I put the stock chargepipes back on, but it's still doing the same thing.... Gotta be a vacuum leak or a bad bpv. I can't seem to find anything.

 

Not sure if it was mentioned, but I know mine fluttered really bad after I got the GMS1 sensors installed without the tune. (installed on a SAT, tune had to wait till MON). This tells me it's something that can be tuned out, assuming the cause is known and the tables are available.

 

Kinda makes me wonder if I have the right reflash..... But I mean my car is boosting 130-140kpa.

 

If the sensors or tune is not right it is sensing the pressure improperly and can cause some surging.

 

So they would have to reflash the car again then

Any way to tell if the tune isn't right.

 

Reflash the car and double check for leaks. I had 3 leaks I had to fix after installing my sensors. 1 at each MAP sensors from the O-rings being too small and one at the extra screw hole on my Coldside pipe. Make sure if you have an aftermarket coldpipe you seal the other MAP screw hole so it does not leak there!!!

 

How did you fix the leak at both sensors. Also I have the stock coldpipe, but one of the screw holes are open

 

IIRC the stock coldpipe is not drilled all the way through like most aftermarket cold pipes so even without the screw in it will not leak. I fixed the leaks at the sensors by buying an O-ring kit from the help section of the auto parts store. I had to lube the orings and the bores really well with some really slippery silicone lube to get them to slide in there. Was kinda tight LOL.

 

Hmmmm it was leaking even with the bigger o-rings that came with the kit?

Also, what's the best way to check for vacuum leaks?

 

Well I even had the lower charge pipe off this weekend to look at it and there is nothing wrong with it. Kinda mind boggling. The only other think I can think of is that it's gotta be the bpv.....

Would the waste gate have anything to do with this issue?

 

Bump...... Any ideas..... My car hadn't been building boost as fast as it usually does since all of this has taken place.

 

OK same issue here and mine has gotten worse. Driving back from lunch yesterday it only made 5 lbs of boost at wot. pulled it in the service drive then it was boosting normal 20 psi. NO CEL so no codes are thrown and this might be a bitch to track down.

HELP!!!!!!!!!!!!!!