30FF Code - zero boost

[joeo]

While on track, engine was running strong, but then after coming off throttle and going back to full, there was zero boost available.
30FF was thrown. I reset codes and drove around the paddock, but regardless of what I did, zero (and I mean zero) boost is created.
Charge pipes do not appear to have leaks, and I've not found any obvious vacuum leaks. Prior to this, I could hear the turbos spinning even by just revving, but that no longer occurs.

Turbochargers are stock. I could see one turbo going bad, but both at the same time seems incredibly unlikely. What should I check?
Thanks!

-joe

[Reppunkamui]

Check vacuum lines and Boost solenoids would be my first stop.

[G3min1]

Time for a smoke test also.

[joeo]

Thanks. I pulled the solenoids and, well - to be blunt, I can suck on one easily and the other not. So they are different.
Going to replace them.

I didn't think it would be the solenoids since there are two of them and two turbos; seems like it would still make some boost, but the way the actuators vacuum lines are plumbed, they are T'd off each other. In other words the actuator vacuum lines from both actuators going to both solenoids is one line.
I wonder if BMW did that to prevent a single turbo from trying to make boost for the whole engine if one turbo failed?

Right now, I'm hopeful it's the solenoids.

-Joe

[wheela]

If only 1 boost solenoid is shot, then that turbo won't be boosting, and may actually act like a big diverter valve, so all the boost from the running turbo may just backflow through the other turbo making it act like a gigantic boost leak. Long story short, I think you're on to something.

[Reppunkamui]

Originally Posted by joeo

Thanks. I pulled the solenoids and, well - to be blunt, I can suck on one easily and the other not. So they are different.
Going to replace them.

I didn't think it would be the solenoids since there are two of them and two turbos; seems like it would still make some boost, but the way the actuators vacuum lines are plumbed, they are T'd off each other. In other words the actuator vacuum lines from both actuators going to both solenoids is one line.
I wonder if BMW did that to prevent a single turbo from trying to make boost for the whole engine if one turbo failed?

Right now, I'm hopeful it's the solenoids.

-Joe

Yeah, it only takes one to cause over/under boost issues. The car should go into limp mode when it detects a problem (might not be necessary/noticeable if its 0 boost). I would recommend replacing both if 1 failed and they are about the same age. The plastic nipples also get quite brittle with age.

[joeo]

Installed new solenoid valves, and same problem.
Datalog:
https://datazap.me/u/joeo/new-soleno...8&zoom=694-891

Duty cycle goes way up, and target boost pressure is ~15psi, but none is actually made. Oddly no check engine light is thrown.
Kinda feels like a charge pipe, but I can't find a leak so far. Need a smoke machine.
What I don't get is that it is zero boost, not a little, not 3psi, zero. Confused.

Here is a video with data when the issue occurred - around 8:20:

[wheela]

Have you verified there is still vacuum at the boost solenoids when the engine is running?

[joeo]

Yes - pulled tubes at the vacuum canisters while running and get a nice psshhhh noise as the canisters fill with air. I pressurized the intake track and there is a minor leak at the one of the intercooler connections, but I'm not convinced it's enough to cause no boost (?).

I pulled the intake pipe off the front turbo and spun it by hand; spins easily and there's very little shaft play. If the rear turbo is seized; would that cause no boost?

[iminhell1]

No mention of wastegate actuators. And really they should be the fist thing checked. High heat can destroy the rear first. Either hose or diaphragm. If both WG's are stuck open you won't make any boost, by design. But with one working and one sorta working you can make 35psi still. LOL.

[Reppunkamui]

Just saw the video. It seemed to spool fine for a long while and suddenly drop off. Assuming that was limp mode kicking in? If it is not limp mode, I would guess that an intecooler or throttle hose popped off... but you would defintely notice it if that happened.

Not sure what else you have checked, but have a look at the charge pipe and intercooler piping for oil or broken O rings. As iminhell1 mentioned the wastegate could be a problem too but I heard the rattle usually comes first.

Good luck. I went through the same and it was caused by a couple of leaking vacuum lines and a dodgy solenoid.

[iminhell1]

Just watched the video too, for anyone else, come in around the 8 minute mark.

And around that time I head what sounds like a hot brake but I'm thinking is a boost leak. Like a vacuum hose blew off. Maybe that's your coupler leak ...

[joeo]

Thanks for help everyone. I put a vacuum pump on each wastegate actuator and they move. They are loose, and there is significant oil in the intake pipes. The car has seen a lot of track time; been tracking it since 2009.

Vacuum lines to the solenoids and to the actuators have been replaced, but they didn't look bad. Also replaced the two lines on top of the engine that lead to the vacuum pump.
Is it possible that I've been running on one turbo and that gate finally broke? I'm going to start the car and make sure both actuators move.

When I pressurized the intake system, air comes out of the crankcase. That doesn't seem right - PCV?

What else?

[wheela]

Originally Posted by joeo

Thanks for help everyone. I put a vacuum pump on each wastegate actuator and they move. They are loose, and there is significant oil in the intake pipes. The car has seen a lot of track time; been tracking it since 2009.

Vacuum lines to the solenoids and to the actuators have been replaced, but they didn't look bad. Also replaced the two lines on top of the engine that lead to the vacuum pump.
Is it possible that I've been running on one turbo and that gate finally broke? I'm going to start the car and make sure both actuators move.

When I pressurized the intake system, air comes out of the crankcase. That doesn't seem right - PCV?

What else?

Not sure how helpful this is, but on n55 we remove the oil fill cap when boost testing the intake tract so pressure doesn't build up in the crank case and blow the PCV valve diaphragm. I believe it's just pressure that leaks past the throttle and piston rings that can build up. I'm not familiar with n54 PCV plumbing, but n55 has a pretty reliable flapper valve that would protect the PCV from boost in the intake, guessing n54 is pretty similar?

I haven't watched the video yet, but regarding your previous comment about what would happen if a turbo seized up, I think it would be a big boost leak, at there would be nothing to stop charge air back flowing through the compressor if it's not spinning. The inlet of the siezed turbo would be at atmospheric pressure, so that charge air would want to flow there. I'm not saying one is siezed, just that I think it would be a huge boost leak if it did. Then again, if an oil line for one turbo clogged up while tracking it may not be too far fetched of an idea that this happened.

[joeo]

Had wife start car while I watched the actuator arms. Both move freely as expected. Pulled vacuum hoses to canister and arms move away (opening wastegate).
At this point, the only thing I can think of is (as wheela said) that one turbo's gate is either not closing (it does rattle) or it is seized up. Since I checked the front turbo and it spins easily, it's onto the rear one. Kinda thinking I'll just drop the front sub frame and pull them both out.

[joeo]

Found the problem. Rear turbo's turbine is - well - it's missing.






Front turbo:


I don't know how the impeller/compressor side looks yet, and I'm concerned about metal in the intake. Going to pull both turbos. Glad the problem has been found though!

[wheela]

Holy turbo carnage batman!!

I'm guessing you're catless, no? I wonder if the turbine made it all the way out the exhaust and onto the race track? Yeah, I'd be curious to see how the compressor looks. If anything came loose, hopefully your intercooler would have captured any shards.

I guess now you have an excuse to upgrade turbos

[tracer bullet]

Originally Posted by joeo

Rear turbo's turbine is - well - it's missing.

Sorry, have to laugh. Agreed it's good to figure it out.

[joeo]

Yes, no cats. Car is track only.
Once I pull the turbos off, we'll see how the compressor/impeller side is. In my head, I can't imagine it will be OK, but I think it is possible. If metal is all over, then it may just make sense to change the intercooler. I won't be able to look at it until next week.

I'm currently planning on going with factory turbos from FCP. Very curious on what failed. Possible that an oil line became clogged, or it simply wore the bearing out and started to wobble (?). It looks like the nut that holds it on sheared off.
Yeah - turbo carnage for sure.

[Afam28]

Originally Posted by joeo

Found the problem. Rear turbo's turbine is - well - it's missing.






Front turbo:


I don't know how the impeller/compressor side looks yet, and I'm concerned about metal in the intake. Going to pull both turbos. Glad the problem has been found though!

Wow!!!

[tracer bullet]

Originally Posted by Afam28

Wow!!!

Dude, don't quote a wall of posts.

[joeo]

Will be interesting to see what it looks like up close once I remove it.
Crazy stuff.
I wouldn't have pulled the downpipes if wheela didn't mention that a seized turbo would be a giant boost leak. Thank you.

-Joe