[N54lover12345]

Hello, I recently got my turbos replaced due to wastegate rattle. Since I’ve got them replaced they have been rattling way more than the old turbos and rattle constantly. I am getting constant 30FF codes and using MHDs live monitoring I can see that the car is not making any boost whatsoever.

Need some help diagnosing this issue, could it be that I have a mayor vacuum leak? Leading to the wastegate actuators to not get any vacuum to operate properly and leading to the wastegate flange to be constantly open thus not letting the car make boost? Or what could this be otherwise? Appreciate all the help, starting to go nuts

Car is a E92 335i 2007

[RBeamR]

I think the first thing you want to check is if there is any play on the wastegate actuator shaft. From the outside you should be able to feel it. This is the most common way of 'turbo rattle' in these engines. Are your turbos really new or used new?
Otherwise you could also feel if there is any play in the rotor shaft

[TunafishE93]

Its possible cause the WG are only closed under vacuum. You can check you vacuum pretty easily, before the solenoid should have vacuum at idle, after the solenoid should pull vacuum with boost.
Or your WG arms are not adjusted correctly.

[Rob@RB]

Assuming your new turbos are quality turbos, with quality wastegates (many on the market are very poor in this regard), it is very likely your issue lies within the vacuum actuation system.

The parts within the turbo are only a part of the equation, the parts in the vacuum actuation system of which external to the turbo are also very important. These vacuum actuation system components external to the turbo consists of:
1) Vacuum lines (always replace with the braided OE lines with turbo replacements).
2) Wastegate Solenoids (can become flaky).
3) Vacuum Canisters (the bungs can crack, very cheap/easy to replace or repair).
4) Vacuum source aka vacuum pump and all connections fore/aft (test vacuum at the source).

If you have degradations in any portions of these systems you may not be getting full vacuum "signal" to the turbo's wastegate actuator, in which case the flapper may lightly touch or bounce around on its mating surface causing varying levels of rattling.

While it is true that turbos that have loose clearance wastegates (whether from being from wear or from bad design) or misadjusted wastegate actuators can also cause these issues, even perfect turbo wastegates with perfectly adjusted actuators can also have the same result if there are issues within the vacuum actuation system.

Rob

[N54lover12345]

After taking a look and feeling around the vacuum lines around the engine bay I’ve found my issue. The vacuum line to the rear turbo wastegate actuator was torn, cut of the part that was torn and put it back on and voila! No more wastegate rattle! Will replace all vacuum lines around the engine eventually but i atleast found my culprit. The car still doesn’t make boost but I am quite certain there is a boost leak somewhere in the system. Car makes a kind of “whistling” noise when I rev at over 1500 RPM 🧐

[TunafishE93]

Thanks for the update, let us know what else you find out.