Hello, I have a 2011 chevy cruze 1.4 turbo with 142000 miles. I have had a turbo underboost code for the last 3 years and have lived with it. Lately though my car acceleration is poor, shifting is poor, fuel economy dropped 3mpg in a matter of a week. Attatched are my live stream data with my car at idle after a 30 min drive.
I can't seem to share picture so I will update this once I get on my computer.
Typical Cruze for you.
If you really want to check it out yourself, here are a few places to look assuming the turbo is not blown:
- First make sure all the hose clamps on the induction piping are all tight. Turbocharged engines operate under pressure, so you don't want any of that sweet boost to leak out from loose piping. I'm talking about the piping from the turbo compressor all the way to the throttle body, including the intercooler (if equipped).
- Vacuum lines are VERY IMPORTANT on turbocharged engines. Vacuum lines are used for proper operation of the wastegate and turbo bypass valve. Make sure all the vacuum lines going to these components are in-tact and not loose/corroded.
- If all the pipes are nice and tight and the vacuum lines are good, check the turbo bypass valve on the turbo itself. Most of the time, this is the culprit for under-boost codes. This valve releases excess boost from the pipes when the throttle plate closes. So if the valve is stuck open or even worn out (they get worn out fast, especially the ones with a rubber diaphragm) it will prevent the turbo from creating pressure in the induction piping.
- The wastegate regulates the amount of exhaust gases used to spin the turbine, thus regulates how much boost the turbo produces. Best way to check the wastegate is by visual inspection while someone revs the engine. The wastegate arm should move back and forth as the engine revs, signifying that it is properly working.
- The last thing to check are the MAP sensor(s) themselves. Dirty MAP sensors can give inaccurate readings to the ECU on how much boost the turbo is actually making. Perhaps try cleaning them.
Good luck to you, hopefully it's not a bad turbo as these other components are fairly easy to replace. LIVE DATA is very important to diagnose turbo issues...I'm looking forward to seeing the uploaded data.
Extremely typical of a car with a failing turbo. They are notorious for that. You’re pretty much at the end of its useful life at that mileage.
Do you want us to diagnose the fault or recommend another vehicle?
