[tony3series]

Sorry this is kind of long but I'm at a loss. Cliff notes and logs at the bottom for those who don't want to read the whole thing.

Performance mods when this started happening was JB4 G5 iso. Car is 2007 N54. Wastegates had been replaced ~35k miles and car currently has ~65k miles on it.

29F3 code kept popping up telling me to replace low pressure fuel sensor but performance wasn't effected. Car ran scary strong in Map 5 autotuning mode. One day I got limp mode and half check engine light. So I replaced the LPFP sensor. That code went away but now I have a 30FF code that I can't get rid of!

I replaced all vacuum lines with high temp silicone, and installed ER chargepipe with Tial BOV. I tested for boost leaks with air compressor, for vacuum leaks, wastegate tests etc.

Followed everything in this post. http://www.n54tech.com/forums/showthread.php?t=13114

Fixed a few very small leaks. Car was holding vacuum just fine. Even tested the vacuum canister etc. was pretty thorough. No more leaks.
http://www.youtube.com/watch?feature...ou3AF_CCp-0dm0
When testing the wastegates they both seemed to move smooth, held vacuum etc. The front wastegate only took about 20cc of pull back on the syringe to create the vacuum necessary to hear the wastegate clink and seal closed. The rear wastegate took about 90-100cc of pull back on the syringe to get wastegate to make the clink sound and seal and close. I don’t know if the rear is designed to work that much differently? Did anyone who did these tests find the same thing?

I decided to adjust the rear wastegate. I turned the rod counter clockwise (when facing the firewall) 2 revolutions and tested again. This time it was closer to 80- 90cc’s to hear the clink. I turned it again counter clockwise 2 more revolutions and this time it took ~70cc to hear the clink of the wastegate closing shut. I didn’t want to go more than that because it looks like most people turn theirs about 2-3 times and get good results.

I couldn't really see the low pressure fuel sensor when I was pressure testing. But didn't see any obvious bubbles (from spraying soapy water around engine bay) and I couldn't hear any leaking coming from that area. But do you think maybe the 30FF is coming from me messing up the low pressure fuel sensor install?

I've heard the actuator arm on front turbo can fall off obviously causing massive loss of boost from one turbo being down. Is there any way to just take a look and see if the front actuator arm has fallen off without taking a bunch of stuff like downpipes off? I'm guessing I would have never held vacuum on the front turbo if this was the case though. I can't visualize the front actuator arm easily that's for damn sure. I have a small mirror that I can extend down into engine bay. Maybe I'll try that. Any other suggestions regarding that?

Thinking about going and getting vacuum pump with gauge to see how much inHg it takes to actuate both wastegates. From what I've read BMW spec is ~5.9 inHg to activate wastegates.

Any help with logs is much appreciated!

Cliff notes:

2007 N54 Wastegates replaced ~35k miles. Currently ~65k miles on car. JB4 G5 iso. Car was running AWESOME! Then after replacing low pressure fuel pump 30FF code pops up all the time at WOT. Sometimes getting no boost compared to target. Sometimes <1/4 to <1/2 of target boost. Have replaced all vacuum lines, installed ER chargepipe with Tial BOV, tested for boost leaks and repaired some small ones. Redid pressure test. No more leaks. Adjusted rear wastegate. Both wastegates hold vacuum but front only takes ~20cc of drawback to seal whereas rear takes ~75 cc drawback on syringe to hold seal.

Log was done with a 3rd gear pull. I think I got up to about 80mph before I had to let off the gas.

I tried to attach the more detailed log that is in excel format but it wouldnt let me. Here's a link to the post I made on N54 tech if you want to check out the excel document style log http://www.n54tech.com/forums/showth...449#post274449

[themyst]

It looks like you may have skipped the obvious... faulty/tired wastegate solenoids.

[tony3series]

Originally Posted by themyst

It looks like you may have skipped the obvious... faulty/tired wastegate solenoids.

I thought about that and was thinking about just buying the replacements to see if that would solve it for me. I couldn't find any faults with them with the testing I did. Tested the wastegates and solenoids for leaks and didn't find any. Followed the directions in this video http://www.youtube.com/watch?feature...ou3AF_CCp-0dm0

And this post http://www.n54tech.com/forums/showthread.php?t=13114

I couldn't really find any other good info on how to test if the boost solenoids are sound. I didn't want to spend about $250 to replace both of them if that wasn't the cause. Maybe I didn't search hard enough.

Any good info/advice on how to test the boost solenoids further?

[C.Pop]

Nothing very useful to say here, but I chased a 30FF for a while and it ended up being wastegate solenoids. Even more interesting, just changing out the solenoids did not fix my slow spool/low boost situation. Changing them out and reflashing the ecu did (and yes, I tried an ecu reset before changing the solenoids). The car is finicky. *shrug*

[Joshboody]

Did the boost issue start IMMEDIATELY after changing the LP sensor?

[tony3series]

Originally Posted by Joshboody

Did the boost issue start IMMEDIATELY after changing the LP sensor?

I'm pretty sure it started the day I was at the track but I don't remember which codes popped up that day. I'm thinking it was there before I even swapped out the low pressure fuel sensor. I know I wrote the codes down somewhere in a log book which is usually what I do when I start having issues with a car. I just can't find the log book anywhere.

[Joshboody]

If it happened directly after changing LP sensor, likely you did something while working on the car... always check what you last touched. Manifold line to DVs for example... not hooked up or broken nipple.