Only 3psi of boost, 2010 cobalt LNF

Amack1970

Amack1970

Well-Known Member
So I filled up at the gas station today. Car was running great. Left the gas station and it felt like my parking brake was on. I actually looked down and checked that it wasnt! The car was super sluggish. So I turned the LCD display on the A pillar to the boost screen and floored it. 3psi! What the heck. So I got home and popped the hood to see if a boost tube came loose. Everything feels tight from the turbo to the intercooler, all the way to the air cleaner. I scanned the car.... nothing. Fast forward a few hours I drove the car again. I had boost for a minute then it was gone again. We to auto zone and had the car scanned had boost both ways? Still no check engine light. Any thoughts?
 
Desert Sasqwatch

Desert Sasqwatch

Goblin Guru
Anthony, someone else was just having this problem, I was reading it last weekend. Do a search for low boost and see what pops up. I will go back and review to see if I can find the thread.

Update: found it. SC/TC Specific section Turbo+Boost issues
 
Amack1970

Amack1970

Well-Known Member
Scanned it twice no codes, but cheap scanners were used. I can plug into it on Monday. What does the waste gate connection look like?
 
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Briann1177

Goblin Guru
I don't have a picture, but the wastegate is on the bottom side of the turbo. It's a can shaped thing with a single vacuum line and a push rod that goes that goes towards the exhaust. Check the vacuum connection and the push rod. I think there is a locking nut on it. Make sure nothing is loose.
 
Desert Sasqwatch

Desert Sasqwatch

Goblin Guru
The rectangular box mounted on the intake manifold between the cylinder 1 and 2 runners with the 3 tubes connected is your boost reference. The hose coming off the 'front' side closest to the cylinder 1 intake runner goes from this box to the waste gate. The hose on the side closest to the engine block goes to your turbo plumbing pipe (pressurized) very close to the MAP sensor. If these are connected correctly it has to be some electrical connection.
 

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Amack1970

Amack1970

Well-Known Member
Talked to Richrich last night. He said to try unplugging the MAF sensor. Just did that and took it around the block. I have boost! Looks like I need new sensor. I think I'll upgrade to the better sensor zzp offers which will require my computer to be flashed again. Thinking about getting their crank vent that takes the place of the oil cap. That requires flash work too. Anything else I need to have written out or into the flash? I'd like to do this once.
 
JeffsGoblin

JeffsGoblin

Goblin Guru
If you want to keep the old sensor, try cleaning it with denatured alcohol. I did this with my 2005 VW Passat TDI. At 145K miles It was running real sluggish... I could only barely give it throttle before is started sputtering, but if I gave it gradual throttle it was ok. Highway on ramps were no fun. I washed the MAF sensor in a ziplock bag with the denatured alcohol and it did the trick!
 
Amack1970

Amack1970

Well-Known Member
Thanks for the tip. Did you soak the whole thing, or spray just the lower half? I'd imagine you dont what to submerge the whole thing, right?
 
JeffsGoblin

JeffsGoblin

Goblin Guru
First I cleaned it really good on the outside and then soaked the whole thing right in the bag. Sloshed it around in there for about five minutes... Let it air dry or you could use a blow dryer (no heat) to speed up the process. Obviously the alcohol will evaporate and you can reinstall. Hopefully this will work for you (if it is just dirty).
 
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nicholas tiratsuyan

Active Member
So we had the same issue and it turns out we had a bad evap solenoid.

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If you want to check if your solenoid is shot you can blow into the end of that tube that comes out of the solenoid. You should not be able to blow any air through it. So far it it fixed our boost issue but its too wet outside to drive it and see if its consistent.
 
ctuinstra

ctuinstra

Goblin Guru
I was wondering that when you mentioned the EVAP but our car didn’t even have the EVAP anymore. Since we have a SS/SC and you have a SS/TC I didn’t know if they we nessesary in the TC model.

I guess if yours was leaking and sucking in air, I could see that. We just plugged ours when we removed it.
 
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