Dear Minis,

My beloved 2009 MCS is letting me down hard right now. When accelerating hard sometimes the turbo spins up and stay strong, on the same drive, next stoplight, the turbo pulls to perhaps 1500-3000 rpm, (varies even in same gear) and then completely stops providing any boost. No codes are being thrown. I've gone up to about 11 miles where I get no boost above ~2000rpm.

I'm not sure where to begin troubleshooting since i'm not getting any codes, perhaps I need to remove the tune and see if that fixes the issue? I don't know if this helps any but it sounds like the re-circ valve is actuating at the rpm where I lose boost, perhaps this valve is malfunctioning but since its aftermarket the codes don't get thrown???

This car has drivetrain mods:
-NM Engineering Intake & Boost Tubes
-Alta Re-Circ Valve
-ALTA FMIC
-Catless DP
-Alta 3" Exhaust
-Stage 2 AP Tune

Anyone experienced this or similar issue before or know what could be causing this? Thought or suggestions would be sincerely appreciated...Thanks

 

Too many variables to determine what it could be. Any one of your mods could be the culprit.

 

It's pretty common to throw codes of some type if you are having boost problems. As you said, maybe the tune is masking the code.

You can check a few things regardless. Use a handheld vacuum pump and check the wastegate. I don't recall the correct vaccum level but you can verify if the wastegate holds.

You can also check the vacuum lines for weakness or leaks.

Good luck.

 

Pull the intake boot off, stick your finger in and try to move the turbine wheel. If there's play in it the turbo is bad and needs to be replaced, if no play the problem is elsewhere....

 

Thanks for the quick replies

The code threw this morning on the way to work

P28b1 Bypass Valve Signal

 

Probably Alta's fault

 

Do you have a boost gauge? Do you know you're actually not making boost?

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