ALH with too much vacuum resulting in over boost (P0234)

[Aaron T]

my bet is on sticking while under boost/load, despite appearing fine while testing at rest. have seen this quite a few times and pretty sure that's what's happening. you could try to spray it cram full of foaming degreaser (like from walmart) and let it soak and actuate the vanes, spray in some more and repeat again, then blow it out the exhaust with relay 109 disconnected while starting. never actually done that but it might work well enough, else need to take turbo apart for a real clean, possibly dremel/sanding off any pitting on the machine surfaces - which is totally fine to do, have done this on wifes car.

Do I spray oven cleaner in the intake side or the EGR hole? Where is relay 109 located?

 

[burpod]

down the egr hole, yes. it would probably help if you unhooked the downpipe and blocked the exhaust side up, even with just some tape, so foaming cleaner will stay up in the vanes... never actually done it this way, but next time i come across a sticky turbo i think i will try it

relays are in the relay panel right above your left foot...

and confirm the actuator is actually at 18hg to hit set screw. it helps to disconnect it to feel the lever by hand without the actuator attached

 

[P2B]

Huh. Mines at 25%… I’m wondering if that’s backwards and means the same thing?

The N75 passes 75% of input vacuum. I forget whether VCDS calls that 75 or 25 % duty cycle and I don't have mine handy

 

[P2B]

down the egr hole, yes. it would probably help if you unhooked the downpipe and blocked the exhaust side up, even with just some tape, so foaming cleaner will stay up in the vanes... never actually done it this way, but next time i come across a sticky turbo i think i will try it

I have had good results by disconnecting the actuator, clamping a pair of 3" vise grips on the lever, and working the lever up and down with the engine idling. Sometimes it takes a while, in which case I've been known to attach a piece of coathanger wire and conscript a helper to work the lever from above while I do something else

 

[burpod]

I have had good results by disconnecting the actuator, clamping a pair of 3" vise grips on the lever, and working the lever up and down with the engine idling. Sometimes it takes a while, in which case I've been known to attach a piece of coathanger wire and conscript a helper to work the lever from above while I do something else

one has to be careful applying a lot of force to it - the vane lever can break - seen a few people with that happen.

 

[P2B]

one has to be careful applying a lot of force to it - the vane lever can break - seen a few people with that happen.

Agreed, use the same strategy you would for a bolt that doesn't want to undo - work it back and forth applying just enough pressure to make incremental progress without breaking it.

 

[Aaron T]

no, numbers dont' ring a bell. set screw looks like it's in correct position, also appears you have an oil leak there, either from boost @ the compressor housing or oil drain line

I do indeed have an oil leak seemingly from one of those two spots. If it’s coming from boost at the compressor housing, will it go away after I fix the over boost condition or is there a bad seal that needs replacing that requires removing the turbo? If it’s coming from the oil drain line, is there a gasket between it and the turbo? I was able to tighten up one of the two torx bolts but didn’t have the right combination of sockets to tighten the other one up (behind the curving drain line). I picked up a wobble extension yesterday that will hopefully allow me to get in there.

 

[Aaron T]

take a log with 011-001, and/or 011-001-004
not enough info really to determine with only boost data, need to know fueling at least

the 2nd log taken was all in limp mode

Here's a log with 011-001-004 https://drive.google.com/file/d/16R1VjiSJsIKfX9IznPmfcKnuOg8TP6YZ/view?usp=drive_link