Waste-gate actuator causing high/sporadic idle

MJOSEPH90

MEMBER
2015 VOLKSWAGEN GTI
2.0L
4 CYL
2WD
AUTOMATIC
71,820 MILES

I recently took my car to the dealership because I was having issues where my car would randomly rev itself sporadically. I suspected it was a vacuum leak of some kind but the dealership is telling me that it’s my waste-gate actuator for my turbo. And that there is no way to replace the actuator without replacing the turbo.
I want to ask if a bad turbo/waste-gate will cause issues with the idle like I’m experiencing?
I don’t want them to throw parts at my car without it being the actual parts causing my issues.
Thanks in advance.

1 Reply

SCGRANTURISMO

MECHANIC
4,897 POSTS

Hello,

I wouldn't think so. Turbo do actuate by a waste-gate opening and allowing exhaust gas to spin a turbine wheel. The turbines wheel is attached to an input shaft which is linked to an output shaft via gears and through gear reduction spin an output shaft with a compressor wheel on it. The compressor wheel compresses the incoming intake air and along with the compressed air charge, extra fuel is added to the combustion chamber making the volumetric efficiency much greater than 100%. This is what produces more power. The problem with the waste-gate causing your idle to run high is I don't believe that an engine at idle would produce enough exhaust to spool up the turbo enough for it to compress the air enough to make your idle go high like that. In the diagrams down below I have included everything I could find in my two resource guides about your vehicle's turbo. Please go through this and keep us informed as to what happens.

Thanks,
Alex
2CarPros

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