So I am experiencing a boost issue. When I step on the gas the boost gauge jumps as normal but it starts to flutter or drop and then regain boost constantly, from 10-24 then back constantly. I checked the BPV and the black rubber piece seemed to stick to the tan front piece (not sure if that's an issue or not). Then I tightened all the intake and charge piping clamps, some were loose (I thought that was the issue). Well after everything looked good and back together I went out and it is still doing it. Also the car seems to buck or hesitate sometimes kinda like the spark plugs are bad but they are new. Help? And ideas

Update: driving tonight my car started to buck really bad again so I coasted to the next area I could pull off the road. Well I left it sit and run and it kept wanting to die on me so I finally shut it off. Well then I tried to testart her and she wouldn't start. I waited 2 min and then it started right up and ran fine home. What the hell?

 

Bump

 

Check for cracks or leaks in the intercooler, check your hot and cold side charge pipes look at the rubber joints where they attach at the turbo and the intercooler. (i blew a hold in the side of mine)
There are no CELs or any lights on the dash at all?

 

Morning bump

 

READ ABOVE POST, AND ALSO THE BOOST solonoid can be bad.

 

Thanks guys I checked the intercooler end tanks (still stock) without taking the bumper off and didn't see anything but I guess I have to do a serious search. But more suggestions please

 

yeah you can do a pressure test, or you can get soapy water spray it all over your cars charge piping ect, or get some dye, and check for bubles or te dye.

 

Can someone chime in. I'm so confused.

 

if you can not understand you really dont ned to be doing anything to to the car at all or you could caue a more serious issue.

it sounds like your car needs to be checked for cels, and also needs to be properly looed at... first look at your 02 sensors to verify they are not grounded out, check for vacum leaks, look for issues you can notice..

 

Still going on. I've checked the BPV, looks good, and tightened all my intake and pressure piping clamps. Checking intercooler and cleaning NAF tomorrow. Any other siggestions

 

Similar problem here. My boost will go up and down but then eventually hold at 20 psi. It does seem like my turbo is working harder on just normal driving and my power has gone down. On the highway doing about 80 it will be at 0 psi when it used to set at around -10 when just cruising. My MPG has also gone down.

So far I have replaced the spring in the BPV to a stiffer spring but it did not seem to make a difference.

Will be checking for a boost leak soon once I have nice day to do so.

 

try your boost solonoid or the k04 wastegate actuator

 

Ok ill give it a shoot. Is there any documentation how to test the boost solonoid and wastegate acuator? (First turbo car so I'm still learning some)

I will put it up on the ramps tonight and look around. Maybe something will jump out at me.

 

found this TSB...checking this weekend.





Service Information 2008 Chevrolet Cobalt | Cobalt, G5 (VIN A) Service Manual | Document ID: 2206771
--------------------------------------------------------------------------------

#PIP4520: Low Boost / Power And/Or DTC P0299 Or P0101 - keywords actuator boost CAC charge control cooler driveability DTC ECM engine gas lnf low maf MIL reduced reducedpwmde SES wastegate - (Nov 4, 2008)


Subject: Low Boost/Power and/or DTC P0299 or P0101


Models: 2008-2009 Chevrolet Cobalt SS Only

2008-2009 Chevrolet HHR SS Only

2007-2009 Pontiac Solstice GXP

2007-2009 Saturn Sky Redline

With Engine RPO LNF Only




--------------------------------------------------------------------------------

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:
A technician may encounter a vehicle with a low boost/power condition and/or DTC P0299 and or P0101 setting. This may be the result of a cracked or broken fitting at the turbocharger assembly.

Recommendation/Instructions:
It has been determined that the nipple for the turbocharger wastegate actuator may be damaged causing this condition. If this concern is noted please inspect the area on the underside of the turbo compressor housing for the wastegate actuator solenoid valve. The nipple (see CALLOUT #1) may have been damaged causing a loss of boost pressure. It may be necessary to remove the charge air duct for a closer inspection. See eSI "Turbocharger Wastegate Actuator Replacement" for solenoid replacement procedure.



This solenoid is available separate from the turbocharger and should be replaced as a sub assembly. Do not replace the turbocharger assembly.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.

WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION


© 2009 General Motors Corporation. All rights reserved.