So, today I was driving home from a place two hours away from my house and my R53 was handling just fine. After a little while I noticed that when I hit boost it didnt have as much kick as it usually did, and when I checked my gague it was only going to 5psi (I usually get 15-16psi) then after I stopped and looked and saw no abnormalities it only went to 2psi and was obviously sluggish in boost. And once when I got on it to pull onto a highway it went into limp mode. Any ideas? I can hear the supercharger whining and making usual strong sounds, and my vacuum on my gauge is still the same. I'm guessing there's a line that got melted? Im running a 15% pulley and Invidia exhaust and tune etc. It also sat in the heat for 2 weeks before I drove it home.

 

It'll be post supercharger' check your intercooler, or the rubber ends that connect it to the horns. The only other things would be the horn gasket on the charger, the intake manifold gasket, or a vacuum line setup. I believe there is a vacuum setup made out of plastic tubing that gets brittle behind the intercooler on the driverside.

 

Also check the bypass valve.

 

When the boots on my IC were not aligned a CEL came up.

If no CEL, my money is on mrbean....

BPV.

With engine off, check to see if there is any spring tension there. Can also zip-tie it closed and see if boost magically appears.

GL.