[BEAR-AvHistory]

Try the reset defaults tab.

[Gugs]

When you trigger that code its always a fairly Large leak. Small leaks rarely trigger the code.
I would just visually inspect your car.
If its not by the throttle body/chargepipe then its One of the intercooler connections which is also easily viewable by just removing lower engine cover.

If your wastegate was failing or malfunctioning its usually pretty loud and rattling.



If all else fails Its under warranty so personally I would just tell the dealer it keeps throwing the low boost code randomly* and to smoke test it.

Takes no time and will give you definitive answers

[Sparky68]

One of the guys at the dyno day commented that the car pretty much behaves how it should upto the point that the psi goes over stock.

[BMWM.D.]

Originally Posted by Gugs

If your wastegate was failing or malfunctioning its usually pretty loud and rattling.

Not always. I've seen several cars lately with the bank 2 wastegate jamming intermittently and no noise or other obvious signs (other than 30ff under hard acceleration).

[Sparky68]

BMWM.D

Thanks for your input.

What would be your plan of attack on my issue? I am going to log map 4 tomorrow [as suggested by one of the forum members] after that if it does turn out to be a leak which i think is possible, [it has been suggested the JB4 is faulty] should i just get it smoke tested?

[Gugs]

Where do you read the word Always in my sentence BMWD?

If the jb4 were faulty it would give you more then just low boost codes so that really doesnt make much sense but who knows.

A 30 second smoke test would solve your guessing

[BMWM.D.]

Originally Posted by Gugs

Where do you read the word Always in my sentence BMWD?

You didn't. But I posted that to let anyone else reading know that you can have wastegate problems without hearing any of the typical wastegate rattling noises. Just relaying what I've personally seen.

Originally Posted by Sparky68

BMWM.D

Thanks for your input.

What would be your plan of attack on my issue? I am going to log map 4 tomorrow [as suggested by one of the forum members] after that if it does turn out to be a leak which i think is possible, [it has been suggested the JB4 is faulty] should i just get it smoke tested?

I mean, it could be a lot of things. I've personally never seen a boost leak on an N54 car that wasn't caused by someone leaving something loose. If the car has aftermarket intercooler, charge pipe, etc. , then that's another story. I've never seen a stock bypass-valve leak, but I know it can happen when the boost is raised. Keep in mind I mostly deal with the OEM stuff professionally. What have you done as far as mods?

9 out of 10 times I see a car with 30FF come in (and no other related faults), it is usually a vacuum control type issue or a wastegate issue. Could be something as simple as a torn vacuum line near the EPDW valves. I'd check all those lines over very carefully.

If you have a vacuum pump (Mity-vac) you can test both the EPDWs for leakage. This is something that I've seen a number of times, and will cause the 30FF fault. If you have that vacuum pump, It's really easy to test. Just see if the inlet side (port that the vacuum reservoir line connects to) of the valve holds a vacuum with the engine off. These valves are sprung closed and should hold a vacuum. If it doesn't, that's a problem. There is a seperate valve for each turbo, but the outlet sides of the valves are T'd together. So if 1 valve is leaking, it will affect both turbos. You'd still have some boost, but the wategates aren't going to do what the DME wants them to.

If your charge air system is stock, I'd definitely start with the vacuum control part of the system. If you've changed things and there is a chance you've introduced a leak, then you may want to start there. In that case, a smoke test could be a good option. Hope that helps.

[neilvosko]

likely charge pipe or bov flanges. get some gasket maker for better seal.

[Sparky68]

Well I ran map4 this morning on the commute into work, lots of WOT and no codes. Guess that rules out the JB4 being faulty?

[CUTigers]

My 30FF code was from worn out vacuum lines, $5 fix. Mine were leaking under the engine cover though on the top front of the engine. When it happened to me, I had only a Dinan S2 tune on it and the increased boost just killed the vacuum lines. Just replace them and was good as new. So a smoke test is what I would do.

[Sparky68]

Map 4 boost still a little under target

[Sparky68]

Originally Posted by CUTigers

My 30FF code was from worn out vacuum lines, $5 fix. Mine were leaking under the engine cover though on the top front of the engine. When it happened to me, I had only a Dinan S2 tune on it and the increased boost just killed the vacuum lines. Just replace them and was good as new. So a smoke test is what I would do.

Got it booked in for a smoke test next week. Hopefully it is something simple.

[CUTigers]

Originally Posted by Sparky68

Got it booked in for a smoke test next week. Hopefully it is something simple.

Ya, hopefully. Of course my vacuum lines went out like a week after the new car warranty did. BMW wanted like $500 to replace the vacuum lines, i was like you are insane, took it to an Indy shop who smoked it for me and fixed it in super fast time and waaaay cheaper and I was rocking and rolling again.

[Sparky68]

Just took mine for a run, made a bit more boost but still got the 30FF, cant wait to get it sorted.

[ken1137]

as E90 mentioned the ER charge pipe and dont forget about Forge FMIC (no trimming) and their DVs since you are in the UK. Good, I was going to mention you need a smoke (boost leak) test. GL

[Sparky68]

OK good news and bad news. Smoke test done, no leaks bad news, they think it is probably the diverter valves not being strong enough to hold the boost. Had wastegates checked while i was there and they are spot on.

So now i guess I buy some lovely forge or other valves and go from there.

[Sparky68]

Swapping boards out tomorrow in the JB4, smoke test was fine, car behaves normally on map 0 so what else can it be? Anyone else had a faulty board?

[2fast4]

Originally Posted by Sparky68

Swapping boards out tomorrow in the JB4, smoke test was fine, car behaves normally on map 0 so what else can it be? Anyone else had a faulty board?

I caught this old post and figured you or someone found out the issue by now?!
I have the same problem with normal boost on stock flash. But tuned map(OpenFlash Tablet) and boost is 5-6psi lower than the target.
I changed the vacuum hoses, even the NEW boost solenoids, air pressure leak test....nothing changes it.

So let me know, please....

[windymissile]

Setting 4/2 active?

[2fast4]

Originally Posted by windymissile

Setting 4/2 active?

What's that?

[jwilliams]

I have been having same issue. Bmw reported back it is a pressure converter not shutting wastegate fully.

[windymissile]

Originally Posted by 2fast4

What's that?

Setting 4/2 is Alternative pedal to boost mapping.
This can sometimes be inadvertently set and cause false low boost codes.

WM