I've been troubleshooting this weird issue that just started for the last week or so and I'm banging my head against the wall. Car was running fine and humming along for like 3 months with this setup, and then all of a sudden it started slowly and it's getting worse. It's hard to describe but it's almost like boost is being vented out. It doesn't happen all the time but when it does it makes a WWSSSSSSHHHHHHHH sound and boost is cut to 1/3 or 1/2 of normal (7-10 PSI vs 20-22 PSI). It seems to happen more regularly as the car runs a bit and gets to normal temperature. I can kind of feather the gas pedal when it happens and usually it will stop hissing and go back to normal and kick my head back.

I've completely disassembled and quadruple-checked all the hoses, including intake, intercooler, vaccuum, etc. I've ordered and tried all different springs in my recirc valve. I've swapped back to stock intake hose, intercooler hose, disconnected the power module. I haven't tried taking the recirc valve back off and putting the stock one back on because it was a pain to get on in the first place. Another thing that may be worth noting is that occasionally I can smell something like burning oil in the car / around the car outside, but I don't see any oil in the engine compartment or have any leaks on the ground under the car.

Car is a 2016 Countryman Sall4 and has ~ 35k miles on it and the list of mods is below. Also, there is no check engine light or fault codes being thrown. If it was a boost leak wouldn't it be consistent EVERY time? Could it be an issue with the recirc valve or wastegate? I also made a video on YouTube where you can kind of hear it...


Any ideas or suggestions at all? Thanks in advance!

Mods:

• Cravenspeed
  • ​Flexpod Quad Gauge Kit
    • Boost Gauge
    • Oil Pressure
    • Oil Temperature
    • Water Temperature
• M7 Speed
  • Oil Catch Can
  • Heat Shield
• NM
  • Power Module
• Alta
  • Cold Air Intake
• Forge
  • Recirculation Valve
  • Intercooler Resonator Delete Hose
  • Intake Pipe
• Ultra Racing
  • ​Front Upper Strut Tower Brace
  • Front Lower Front Brace
  • Front Lower Middle Brace
  • Front Lower Rear Brace
  • Middle Lower Brace
  • Rear ​Lower Brace
• Sprint Booster V3
• 2nd Cat and Resonator Delete

 

Update: Spent some more time on it tonight. Put the factory diverter valve back on and it's fixed! So apparently either there's a vacuum leak, an issue with the solenoid, or the valve itself got messed up. I find it hard to believe that I developed a vacuum leak via driving for 2 to 3 months and nothing else has changed? Have you seen the Forge valve or solenoid that comes with it fail? Or should I order some higher quality vacuum lines? If so, any recommendations?

 

I was going to suggest the Forge valve sticking. The aluminum body coming up to temperature, not enough lube... Depending on the conditions, intermittently sticking would cause some boost fluctuations. The factory valve being all plastic wouldn’t be as sensitive to temperature rise, and would work better when up to operating temperature.

It’s been reported here that the latest diverted valve design will hold 20-22psi boost just fine. If your OEM valve isn’t that version already, my suggestion would be to ditch the Forge valve and get one of those.

 

I'm not sure my OEM is the latest but it's a 2016 model car and I put the original back in and it's working properly again.