I have a 06 cobalt ss s/c with only 40k miles. I am having a problem with boosting past 5 psi. I will do a 2nd gear pull at 3500 rpms and the most i will boost is 5ish psi. My lines are fine and not dry rotted. I do feel a little power loss. It has been a little hot in NJ, could that be the issue as well? Also when i turn my ignition on (but don't start it) my needle does not sit at 0 it goes on -2.5. Could it be the gauge? My only mod currently is a Injen cai.
PLEASE HELP ME

 

Don't know about the not boosting past five,
But, with the needle reading -2.5 when engine
is on and not running. That could be nromal. Depends on the weather, and
your elevation. Sometimes mine reads negitive too. The computer
is looking ath the absolute pressure, then its computed diffrential pressure,
based on it the outside air being 29.92". If there is a low pressure system,
or your somewhat above sea level, it could read in the negitives.

 

Check the coolant level in ur heatexchanger reservoir and make sure its full

 

I didnt know about that. Hopefully that could just be the issue. I read somewhere that the stock boost gauge is wired to the computer to get its psi reading and not the vacuum line. Is there a way i could check to see if everything is not shorting out or anything on the gauge?

 

I got an oil change the other day and they top off all my fluids as well. So they are all full. Any other suggestions?

 

IDK I just posted that because I was having a problem building boost and I found my heat excharger reservoir was low on coolant and after I topped it off the problem went away

 

check your engine bay,you might not even be boosted

 

it could be a bad sc gasket. my car back in the day had a bad boost leak and wouldnt go past 10lbs so i took it to the dealer and it was the supercharger gasket. after the fix it ran like a charm........that was my problem though; and my car had 20k on it at the time.

 

Funny guy

 

I had the same problem. Once I started to boost any, my car would try and power down. To get down to the point,

Chevy has a recall on the catalytic converter. I had it replaced and I instantly had my boost back. Before you go changing anything, call you local Chevy dealer and ask them. It was only for the 2006 SS/SC.

Hope this helps you out!

 

jk sounds like you either got a vac leak or something is wrong with the bypass thing

 

That seem to be the most reported on the other threads, but there are no cracks nor dry rotted.

I will give them a call tomorrow and see how it goes with that recall. Thanks

 

i would hate to have to rip out the s/c, but will keep it as a consideration.

 

The stock boost gauge IS wired to the PCM. If you have an intercetpor, you can bring up your boost on that, and compare the two.

To check if the wires are shorting, the best way to do that is take off your A Piller, and look at them.

I have removed my stock boost gauge and replaced it with an Analogic gauge, and installed a seperate boost sensor from Aeroforce for it.

 

Well have u tried the boost bypass if that helps u boost pass five then change the bypass valve on the sc

 

look into it,That controls your psi levels

 

Honestly, just call a GM dealer. I was having the exact same problem and I was getting pissed cause I kept replacing stuff and I even bought some SC oil and was about to change it and I got the letter from GM. I took it right in to my local Chevy dealer, and they replaced the Cat and that fixed the boost problem. My car is completely stock too.

 

if the cat bad you will have higher boost levels and the recal was for redlines- balts not just 06 if you do the boost bypass mod you take to parts out of the system 1 being boost bypas actuator and 2 being the boost bypass solenoid the booost bypass solenoid has causedmore problems

 

this be your problem. The second nipple on the bypass valve actuator, when plugged, causes the supercharger to boost only 5psi. Leaving it open to the atmosphere allows full boost (it's the way the ECU electronically controls boost, but remove it for testing purposes and see if you still have the problem)
im 95% sure you have an actuator problem

 

good point but if the boost bypass solenoid is bypassing internaly it will also cause low boost also