Resolved: Fluttering?

[ncbimma]

Trying to diagnose the X5m. I'm getting some sort of flutter and low boost codes and now misfires. Anyone heard this before...is it the wastegate not holding pressure? Or a vac leak somewhere?

https://photos.app.goo.gl/ewzABbf8HtjbPaV3A
https://photos.app.goo.gl/W9Sv314afTSogTiR6


Any ideas?

Bms stg1 / fabspeed exhaust mods

Now any WOT driving or harder acceleration cripples the car into limp (low power mode).

I'm sure I crapped out the plugs or coil..but that flutter is odd to me.

[9vapors]

Maybe the valves are staying closed in the exhaust? Did the hose maybe pop off?

[ncbimma]

No valves in the fabspeed. They are omitted. I've plugged off the 2 vac lines where the actuators were and dbl checked they are sealed.

They are bound with 3 bends and are golf tee plugged and ziptied.

That was my first check.

[ncbimma]

So I went ahead and removed the stage 1 tune in hopes the aggressive boost map was causing the issues.

Able to run the car just fine but it does seem sluggish on speed but still quite responsive throttle wise. I feel there's some boost leak causing this.

I removed the stock air box and put 2 cone filters in place to hear more accurately. The result:

1) The flutter on throttle (building boost) still happens
2) Car seems to still return air when quick releasing accelerator
3) No more low boost CELs triggering

So my thoughts are boost must be holding to an extent but escaping fractionally on boost build somewhere.

My stg 1 probably damaged something old with the tune and now it's still broken even though normal.boost has resumed.

Anyone have an easy vacuum diagram or must check points in the engine?

Thanks!

[9vapors]

https://f10.m5post.com/forums/showthread.php?t=872199

Try testing the wastegates like in the first comment in the above thread?

[ncbimma]

Originally Posted by 9vapors

https://f10.m5post.com/forums/showthread.php?t=872199

Try testing the wastegates like in the first comment in the above thread?

I drive in sport mode most all the time (unless wife and kids are in car!). So the WG should be delayed- I'll test it out in the morning to see if the flutter eliminates in one scenario or not.

The sound I'm referring is on the building of boost at the beginning of the throttle press. There's a flutter like something is messing with the turbo spool or vacuum leaking repeatedly at a certain pressure or something weird.

But there is still enough pressure built to give a proper recycled air 'whoosh' when releasing the accelerator which has me confused.

(I've had a 18# boosted A4 before so I'm not that new to FI...just new to this X5M)

I wonder if a constant misfire would sound like this..but I've no reoccurring code after clearing them initially.

[ncbimma]

Resolved:

Cylinder 1-4 air duct cracked
Cylinder 5-8 air duct cracked

Replaced all breather hoses too...

Boost is back baby!

Time to step up my spark plugs and coilpacks to support my BMS tune!