[eguti335i]

So i recently installed JB4 and last night a 30FF Code - Low Boost popped up.. i got home turned off the car and restarted in 20 mins later.. light gone, however jb4 still reads the 30ff code when searching through the dash.

the code came while on the hwy, going around 100mph(testing jb4) in 6th gear. around 3500-4000 rpm.

ive read many discussions about the possibility of a boost leak via charge pipe, intercooler, or maybe vacuum.

Ive also read a few comments about the possibility of a 30ff code being related to fuel pump, vanos, or coils/plugs. is there any chance this 30ff code can be related to these issues?

[RCOLEMAN545]

I would start with replacing the vacuum lines, especially if they are the original. I had a similar problem, a leaking line was the culprit. Good luck.

[gabylonfive]

i'd wager a guess that it's a vacuum leak. pretty common especially on older lines as they get hard and brittle. check the lines that run over the ofh - gets pretty hot over there.

[eguti335i]

yeah its a 2008 335i, the lines may be done.. ill start there, i eventually plan on replacing the charge pipe and intercooler very soon, so if its not a line ill eventually replace the other possibilities anyways.

just to be clear, this 30ff code has nothing to do with VANOS or fuel pump right? any relations between the two?

thanks for the input btw, very appreciated!

[Clownaround]

Similar problem here. I've had a 30ff code ever since I have tuned the car under medium to hard acceleration. When I take the tune off, I can't get the 30ff code no matter how hard I push it. I've replaced the most of the easy to get vacuum lines including the ones under the engine cover. Even found one completley ripped and hanging by a thread. Thought for sure replacing the ripped vacuum line would fix it but still I'm getting the code. Could bad wastegates be the cause of 30ff? I think I will try the smoke test mentioned a few months ago in another thread...The only lines I havent changed were the ones coming from the turbos. Also changed out my Charge pipe and and am using a bov instead of the diverter valves which I heard was another 30ff suspect. Any ideas?

[Jeff@TopGearSolutions]

Originally Posted by Clownaround

Similar problem here. I've had a 30ff code ever since I have tuned the car under medium to hard acceleration. When I take the tune off, I can't get the 30ff code no matter how hard I push it. I've replaced the most of the easy to get vacuum lines including the ones under the engine cover. Even found one completley ripped and hanging by a thread. Thought for sure replacing the ripped vacuum line would fix it but still I'm getting the code. Could bad wastegates be the cause of 30ff? I think I will try the smoke test mentioned a few months ago in another thread...The only lines I havent changed were the ones coming from the turbos. Also changed out my Charge pipe and and am using a bov instead of the diverter valves which I heard was another 30ff suspect. Any ideas?

Anything related to the charge system can cause a 30FF.

So boost solenoids, wastegates, pre turbo pipes and post intercooler charge pipes.

It can even be something as small as the o ring at the throttle body or at the TMAP of the charge pipe.

Without pressurizing the system it's hard to say where from here.

As a side note, stock tune is only 7 PSI, when you tune your car you typically double the PSI, things start to flex a lot differently when you double the pressure, that's why you can't get it to do it stock.

Only downside to a smoke test is most don't pressurize the system. You need to pressurize to atleast 15-20 PSI so things can expand and mimic a full load and boost pressure.

Did you check the boost/vac line to the intake manifold? I'd replace all lines if you haven't already.

[Clownaround]

Originally Posted by Jeff@TopGearSolutions

Anything related to the charge system can cause a 30FF.

So boost solenoids, wastegates, pre turbo pipes and post intercooler charge pipes.

It can even be something as small as the o ring at the throttle body or at the TMAP of the charge pipe.

Without pressurizing the system it's hard to say where from here.

As a side note, stock tune is only 7 PSI, when you tune your car you typically double the PSI, things start to flex a lot differently when you double the pressure, that's why you can't get it to do it stock.

Only downside to a smoke test is most don't pressurize the system. You need to pressurize to atleast 15-20 PSI so things can expand and mimic a full load and boost pressure.

Did you check the boost/vac line to the intake manifold? I'd replace all lines if you haven't already.

Thanks for the tips Jeff. I have replaced the vac line running to the intake and all of the lines topside. I need to find someone with smaller hands to help with the lines running down to the turbos. After that, solenoids were going to be my next replacment followed by new turbo/turbos if that didnt fix it.

[eguti335i]

yeah ill try changing all of my vacuum lines tomorrow afternoon when i have some light.. that may be the cause.

a smoke test is probably ideal to find any sources of these leaks, it seems like the only way to know for sure.

thanks for the advice, ill post if i get any solutions.