30FF Boost Issue

[delta-9-ginseng]

Can anyone recommend a shop in the bay area that can help with a 30FF boost issue? Or at least is familiar with the N54 engine and all its quirks. I don't really want to go to BMW SF if I don't have to. I have a feeling it might be wastegate related, unfortunately. The car is a 2008 BMW 135i with 55k on it. Thx for the help

[1mang]

Underboost code. You have a small leak somewhere. I would go check the most common areas first and then slowly go towards more expensive fixes.

1) Inspect vacuum lines. Might be a good idea to just replace all anyways since your car is 9 years old.

2) Inspect diverter valves. Are they fully seated? Might as well upgrade the inner o-rings since you are inspecting them (refer to this thread http://www.german**********/showthre...ter-Valve-Seal) I have tons new available to give away. PM me if interested.

3) Inspect intercooler connection (do you hear a "whooshing" noise after you left of gas between shifts? Sounds like BOV...but without the power lol)

4) Inspect wastegate solenoids. These tend to go bad. Wouldn't hurt to replace since its around $75/each

Do you hear a rattle after you rev? If you do, try to rev again but unplug one of the vacuum lines to the boost canisters (bottom left of engine bay...there's two of them) If this is the case, time to complain to BMW and have your turbos replaced under that extended warranty...you might be at the cut off at 9 years...If you are, time to replace turbos.

[delta-9-ginseng]

Thank you for your help!

I actually had both the vacuum lines and solenoids replaced in December. I do hear an unpleasant rattle/metallic sound when I first turn on the car. Sounds very mechanical, not in a good way lol. I have no fault code when I first turn on the car, it's only when I go above a certain RPM (~2800-3K) is when the 'limp-mode' check engine light comes on. I go about my business and then come home park the car and turn it off. When I turn it back on again the fault code is gone. Does this mean that the boost cannot be generated at higher RPMs and therefore throws a code to protect itself? I mean I can still drive it's just super underpowered and slow.

I think you may be right about the turbo replacement...ugh

Thx again

[1mang]

Originally Posted by delta-9-ginseng

Thank you for your help!

I actually had both the vacuum lines and solenoids replaced in December. I do hear an unpleasant rattle/metallic sound when I first turn on the car. Sounds very mechanical, not in a good way lol. I have no fault code when I first turn on the car, it's only when I go above a certain RPM (~2800-3K) is when the 'limp-mode' check engine light comes on. I go about my business and then come home park the car and turn it off. When I turn it back on again the fault code is gone. Does this mean that the boost cannot be generated at higher RPMs and therefore throws a code to protect itself? I mean I can still drive it's just super underpowered and slow.

I think you may be right about the turbo replacement...ugh

Thx again

Limp mode you are experiencing is part of the underboost. If you do a scan, you will see its a pending code (even though SES light is not on). It only happens above a certain RPM because the boost is building up but it is not matching the PSI that the ECU is requesting. So it is just letting you know something is wrong and goes easy. Check your connections on intercooler and diverter, charge pipe area (could pop off from throttle body!)

Sounds like you have the dreaded wastegate rattle. Next time when you start up the car and let it idle, remove one of the vacuum lines on those boost canisters. If the rattle goes away, it is wastegate. Time to replace turbos. You could decide to upgrade turbos now. This usually means you need to remove the turbo and send it off to a shop to rebuild. Causing downtime. I have a spare set of OEM turbos I can sell to you if you like to go that route. Otherwise, try to get dealer to replace for free or just buy online and go to indie shop to do it. I have a shop that did mine that I recommend. PM for more details.