Wastegate actuating during boost leak test...

[Bike Muff]

Apologies if this has been covered.

Having intermittent loss of boost, sometimes fine, sometimes no boost. Feels like wastegate or bypass valve issue that comes + goes under no particular circumstances. Full 12+ psi, then suddenly down to 2 psi max.

Waited for the problem to show up, did a boost leak test and no unusual leaks. However the wastegate is actuating during the test. Unhook the hose from the solenoid to the actuator and the wastegate pops closed like it should. Meanwhile the the hose i unhooked is and its bleeding pressure.

I think the wastegate actuator solenoid is stuck open. It's only supposed to divert pressure to the wastegate when the computer tells it to open, right? Its normally closed until the computer pulses it open, correct?

Thanks for any info..

 

[jjrae1]

Does it happen more so when going uphill under load? I had this issue in mine it was happening before i bought it at a dealership i worked for they had it sent to a chevy dealer and they said that the turbo housing cracked (which apon research i found is pretty common). another thing is power wouldn't return until i turned off the car or reset the codes while driving if i really needed the power. it would happen at first mainly in 4th or 5th gear going up hill at around 60-75 mph on the interstate then progressed to happening more frequently at lower speeds and gears... hope this helps!

Sent from my SM-G973U using Tapatalk

 

[Redstealth69]

I had a similar issue. Wastegate would open causing limp after a pending underboost code. Since I had just bought the car I didn't think anything was wrong, just a small engine trying to keep up on the highway. No CEL for a few months until it finally came on due to underboost condition. Did a boost leak test and it seemed ok. Installed the cruzekits v3 pcv mod and still had boost issues. At this point I just said screw it and bought a new oem turbo and oil lines and swapped in the new one on a Saturday. At 90k miles the old turbo had HUGE cracks in the housing at the wastegate port and the wastegate shaft had a ton of play in it. After the new turbo went in the car woke right up, no issues since then. Looking back at it I could've probably machined a new bushing for the shaft and welded the cracks but I needed the car for work and didn't have time to mess around. I hope this helps!

 

[Redstealth69]

I had a similar issue. Wastegate would open causing limp after a pending underboost code. Since I had just bought the car I didn't think anything was wrong, just a small engine trying to keep up on the highway. No CEL for a few months until it finally came on due to underboost condition. Did a boost leak test and it seemed ok. Installed the cruzekits v3 pcv mod and still had boost issues. At this point I just said screw it and bought a new oem turbo and oil lines and swapped in the new one on a Saturday. At 90k miles the old turbo had HUGE cracks in the housing at the wastegate port and the wastegate shaft had a ton of play in it. After the new turbo went in the car woke right up, no issues since then. Looking back at it I could've probably machined a new bushing for the shaft and welded the cracks but I needed the car for work and didn't have time to mess around. I hope this helps!

Update, the car now has 114k and I am experiencing an underboost condition again. No apparent leaks in the piping, goes into limp mode on the highway under load. If this new turbo has failed already I am going to get rid of the car. Garrett is a well known turbo but this is getting old. Oil supply and return lines were replaced with the turbo. Im starting to lose faith in this platform!