2C86 charging pressure / limp mode after valve cover replacement

[LoloHaole]

Car: 2011 e82 135i, N55, manual, 75k miles.
Upgraded intake, intercooler, charge pipe, turbo inlet/outlet, diverter valve, catless downpipe, MHD stage 2+ tune. Been running for over 2 years on this set up with zero problems. Normal spirited driving, no track days.

IDK if this is just WEIRD timing or something I did wrong... After replacing my valve cover yesterday, topping up the oil and starting the car last night, it seemed to idle fine and didn't give any codes. I let it idle for 20-ish minutes to burn off some of the oil that leaked onto the header when I did the swap, then turned the car off for the night.

Today when I started the car there was a WEIRD "grinding" sound coming from the air filter on my Injen intake that sounded like the turbo was turning with no oil. (Not sure what it was, just that's what it kind of sounded like). The sound went away after about 10 seconds and the car sounded mostly normal, but the idle didn't seem as smooth as usual.

I took it for a test drive and as soon as I gave it gas to take off onto the main road, it sputtered, had almost no power, and went into limp mode. The codes are:

2C86 - Charging pressure - ambient pressure, comparison: Charging pressure too low
2C58 - Charging pressure control: Switch-off as consequential reaction

Shadow codes:
2BD3 Fuel high pressure on enabling of injection: pressure too low (probably from disconnecting the injector lines for the valve cover job?)
2BF0 (the description is all in german...)
2C7F - Boost pressure sensor. Multiple fault

I double checked all the connections to make sure nothing was left disconnected and it all seems fine.

When I rev the engine while parked, there's an odd kind of whining sound that isn't normally there. It sounds like it's coming from the intake.

Doing some searches for 2C86, in addition to it possibly being a turbo gone bad, one thing I saw that it could be is a blockage in the inlet somewhere.

So thinking it through, the only thing I can come up with that I might have done to cause this is that when I took off the intake, I put a paper towel in my aftermarket turbo inlet since it sits face up, and I wonder if I somehow left it in there when I put the intake pipe back on it.

I can't imagine how I could have done that since I have to look down at the wide open inlet to reattach the intake, but it was getting dark and I was tired so *maybe* that happened and the paper towel got sucked into the turbo.

Any ideas?

Thanks,
Lolo

[LoloHaole]

Maybe it's the Boost Solenoid...?

"This solenoid is inline with the vacuum pump and allows for constant boost pressure. Some indications that this solenoid is faulty is boost loss and odd noise from the solenoid."

https://www.fcpeuro.com/products/bmw...AaAk_yEALw_wcB

[LoloHaole]

I was able to record the last few seconds of the weird sound coming from the intake/turbo on cold start

https://youtube.com/shorts/6rfgioS-0Qk?feature=share

Have you ever had a turbo make a sound like that?

[Baileyboo]

If you’re concerned about leaving something in there you might pull of the intake and take a look at the compressor wheel if you have an inspection camera. Or take the look at the intake side of the inter cooler to see if there are any remnants in there.

[LoloHaole]

The more I think about it, the more I think I didn't leave that paper towel in the inlet, but I am going to get an inspection camera just to make sure.

Originally Posted by brockott

If you’re concerned about leaving something in there you might pull of the intake and take a look at the compressor wheel if you have an inspection camera. Or take the look at the intake side of the inter cooler to see if there are any remnants in there.

[LoloHaole]

So it turns out I DID leave the paper towel in there and it had gotten sucked up right against the turbo wheel and compacted down. It had a nice imprint of the turbo blades and the center spindle on it. Pretty trippy, but even more amazing is that it was all in one piece.

I used an inspection camera plus a flexible grippy tool to get it out, cleared the codes and it's all good.

It's a huge relief, but holy shit do I feel like a dumbass. Still, it's a lesson to use shop rags that hang out over the edge and also to stop working when it's getting dark and I'm dragging ass.

Peace out,
Lolo