[kazbek1]

I've been having an issue when I'm WOT and hit about 100mph (not sure what the RPM is at), the half engine light pops up. The car doesn't go into limp mode (no reduction in power) although I do pull over immediately if possible to restart the car.

I only have the 30FF code when that happens. I could drive for months and not hit 100mph and will not see the engine light/30FF. I thought I fixed this issue over the summer by replacing my vacuum lines and both boost solenoids as well as checking all of the intake and intercooler lines but it's back. I do have some nice wastegate rattle going on and being that the car is at 135k miles, my turbos may be on their way out. I plan on doing a smoke test soon to hopefully pinpoint the leak (hopefully not the turbos).

Is it safe to continue driving when that light pops up and I'm not in limp mode? Is it necessary that I pull over and restart the car?

Any reason why it would only pop up at WOT around 100mph and not earlier at lower speeds?

Am I correct in assuming that this is caused by a vacuum leak since I get a 30FF code? Could it be from anything else?

[feuer]

2-3psi bellow target for certain time frame like 2-3sec would trigger 30ff. At higher speed the load is greater and engine spend longer time making 2-3psi bellow target and trigger 30ff. At lower speeds the load is less and engine spends less time making 2-3psi bellow target so you don’t get 30ff. It’s parameters. Like a formula. Not only psi dependent. 30ff always come with 3100 which is limp mode. You can continue driving but won’t have boost at all.

[whyzee125]

It won't hurt anything to keep driving like this but if turbos are original and rattling, your wastegates are likely just too sloppy to meet the target boost. Definitely check for boost leaks first but I would plan on replacing turbos in the future.

[kazbek1]

Originally Posted by feuer

2-3psi bellow target for certain time frame like 2-3sec would trigger 30ff. At higher speed the load is greater and engine spend longer time making 2-3psi bellow target and trigger 30ff. At lower speeds the load is less and engine spends less time making 2-3psi bellow target so you don’t get 30ff. It’s parameters. Like a formula. Not only psi dependent. 30ff always come with 3100 which is limp mode. You can continue driving but won’t have boost at all.

Thanks for the reply, man. I'm going to try and log a pull from 3rd gear at about 2500 RPS and see what I can read from that. I have a feeling it may be time for new turbos.

[kazbek1]

Originally Posted by whyzee125

It won't hurt anything to keep driving like this but if turbos are original and rattling, your wastegates are likely just too sloppy to meet the target boost. Definitely check for boost leaks first but I would plan on replacing turbos in the future.

I'm going to check for boost leaks again I guess but I thnk you're right about the turbos. I adjusted the rear wastegate actuator rod (gave it a 2.5 turns) a while back and might try the washer trick for the front turbo. But yea, I should probably start shopping around for some turbos.

[kazbek1]

UPDATE: I checked the vacuum from my boost solenoids (teed off the lines to a brake bleeder vacuum gauge) and tested the pressure at different wastegate rattle fix values. I adjusted the fix on MHD from 0 to 80 and then OFF to see what the readings were. When I started the car at 0%-30% fix, the psi would start at 13.5 but then drop to 4psi after about a minute. From 40%-50%, the psi started at 13.5 and dropped to 11psi after a minute. 60% went from 13.5 to 12.5 psi, 70% stayed at 13.5 psi, 80% went from 13.5 psi to 16 psi and with the feature turned off, it also went from 13.5 psi to 16 psi after a minute.
The wastegate rattle fix was only effective from 0-15% but because those values drop to 4 psi, I'm just going to keep the wastegate rattle fix off. I'm glad to see that the solenoids and wastegates hold 16 psi which to me shows that my low boost must me coming from a vacuum leak. Am I correct in assuming this? I haven't logged another run yet but if I still have low boost on that log, will this confirm that there is a vacuum leak? Or could it still be a turbo issue? I checked all the hoses and connections and everything still looks fine. I'll do a smoke test soon too. Just need to get my hands on a cigar.

[Saif2018]

Originally Posted by kazbek1

UPDATE: I checked the vacuum from my boost solenoids (teed off the lines to a brake bleeder vacuum gauge) and tested the pressure at different wastegate rattle fix values. I adjusted the fix on MHD from 0 to 80 and then OFF to see what the readings were. When I started the car at 0%-30% fix, the psi would start at 13.5 but then drop to 4psi after about a minute. From 40%-50%, the psi started at 13.5 and dropped to 11psi after a minute. 60% went from 13.5 to 12.5 psi, 70% stayed at 13.5 psi, 80% went from 13.5 psi to 16 psi and with the feature turned off, it also went from 13.5 psi to 16 psi after a minute.
The wastegate rattle fix was only effective from 0-15% but because those values drop to 4 psi, I'm just going to keep the wastegate rattle fix off. I'm glad to see that the solenoids and wastegates hold 16 psi which to me shows that my low boost must me coming from a vacuum leak. Am I correct in assuming this? I haven't logged another run yet but if I still have low boost on that log, will this confirm that there is a vacuum leak? Or could it still be a turbo issue? I checked all the hoses and connections and everything still looks fine. I'll do a smoke test soon too. Just need to get my hands on a cigar.

https://bmwtuning.co/bmw-n54-30ff-en...-repair-guide/

Thats a good guide on how to deal with 30FF code, also would recommend you thoroughly check all connection points including charge pipe etc, the vacuum canister points, top and bottom, they can crack and hoses can split there as well.

[kazbek1]

Originally Posted by Saif2018

https://bmwtuning.co/bmw-n54-30ff-en...-repair-guide/

Thats a good guide on how to deal with 30FF code, also would recommend you thoroughly check all connection points including charge pipe etc, the vacuum canister points, top and bottom, they can crack and hoses can split there as well.

Thanks man. That's actually the guide I used to try and find my issues. I've already replaced the vacuum lines with silicone lines and all of my connections seem secure. Seeing as I don't get 30FF on startup and only when I step on it in higher gears, I think the connection points are fine.

I have wastegate rattle and already adjusted the actuator arm about 2.5 revolutions back in March. Maybe I'll try to tighten it again? I might look into wedging a washer or 2 between the front turbo wastegate.

[Saif2018]

Originally Posted by kazbek1

Thanks man. That's actually the guide I used to try and find my issues. I've already replaced the vacuum lines with silicone lines and all of my connections seem secure. Seeing as I don't get 30FF on startup and only when I step on it in higher gears, I think the connection points are fine.

I have wastegate rattle and already adjusted the actuator arm about 2.5 revolutions back in March. Maybe I'll try to tighten it again? I might look into wedging a washer or 2 between the front turbo wastegate.

That's godd to hear, have you checked boost solenoids as well?

[kazbek1]

Originally Posted by Saif2018

That's godd to hear, have you checked boost solenoids as well?

Yea they seem to be working fine. I did replace both of them about 2,000 miles ago so they should be good. I don't know why I didn't think about this earlier but I think I can test each wastegate individually. Theres a vacuum line the runs from each solenoid to their respective wastegate. I'm going to disconnect the vacuum line from the solenoid end, attach a brake bleeder/vacuum to the line, apply pressure to the wastegate manually but pumping it up to like 26psi or so and see if the wastegate holds pressure. If I see the pressure begin to decrease, I can assume my wastegates are leaking and causing the vacuum leak. Hopefully I don't see that in both wastegates and that'll pretty much verify that there's just a vacuum leak somewhere.

My bad for the long, drawn out dialogue and explanation. Just thinking out loud but also explaining in more detail in case someone else is in the same boat and is looking at this post for help.

[Saif2018]

Originally Posted by kazbek1

Yea they seem to be working fine. I did replace both of them about 2,000 miles ago so they should be good. I don't know why I didn't think about this earlier but I think I can test each wastegate individually. Theres a vacuum line the runs from each solenoid to their respective wastegate. I'm going to disconnect the vacuum line from the solenoid end, attach a brake bleeder/vacuum to the line, apply pressure to the wastegate manually but pumping it up to like 26psi or so and see if the wastegate holds pressure. If I see the pressure begin to decrease, I can assume my wastegates are leaking and causing the vacuum leak. Hopefully I don't see that in both wastegates and that'll pretty much verify that there's just a vacuum leak somewhere.

My bad for the long, drawn out dialogue and explanation. Just thinking out loud but also explaining in more detail in case someone else is in the same boat and is looking at this post for help.