[JamesM3M5]

Just thought I'd share:

335xi 6MT. Complaint is of 30FF code, no other codes. Car builds boost just fine when accelerating moderate/hard. Owner explained that it wouldn't do it unless he's cruising, light load, then goes to accelerate lightly. Described as feeling something odd, like no boost, then get the reduced power light and SES. Shut off, restart, no problem.

Found a bad wastegate control solenoid. One you could pull vacuum on it, and it would hold with nothing else connected. The bad one would not hold any vacuum. Both wastegate actuators were fine, moved as soon as vacuum was applied manually, and were completely shut by about 7 inHg vacuum. No boost leaks, since it held full boost/hard driving and never went to limp. Vac pump pulled 25 inHg at idle.

I guess when it was trying to just build a very small amount of boost, the bad solenoid was bleeding off too badly. But when you ran hard, the increased vacuum supply from the pump and the working solenoid was able to actuate both WGs just fine. The problem only occurred under light load going to light acceleration.

[Rob@RBTurbo]

Good info. Thanks!

[._.]

Sounds like a problem I have been having. What is used to apply the vacuum manually and measure said vacuum?

[themyst]

Yep has a bad rear wastegate solenoid on my old 135i. When it fails it reports as a boost leak.

[JamesM3M5]

MityVac is an affordable hand vacuum pump, and some come with gauges. You can use them to suck brake fluid from the caliper nipple, too.

[JamesM3M5]

Originally Posted by themyst

Yep has a bad rear wastegate solenoid on my old 135i. When it fails it reports as a boost leak.

Technically not a boost leak, just failure to attain the specified boost, which is due to the poor operation of the wastegates caused by the bad solenoid.

[Joshboody]

Hey James if i tested each solenoid at idle with wgdc at 60%. Each one showing 17", this would mean working correctly right... Or could i be missing something?

The reason i ask is because i'm trying to troubleshoot what i think is higher wgdc than the norm. Vacuum lines are solid, solenoids seem to be good, intake piping solid but not pressure tested... I will be borrowing an air compressor sometime i hope. DVs open and hold with vacuum.

My thought is that the front wg could be sticking when hot. Trims also show consistently more fuel usage on bank 1.

When cold and applying vacuum each wg seems to close at similar vacuum.

Cars running great despite this.

I had some issues building boost a couple times and after troubleshooting and deciding it could be a sticking WG, i changed my default wgdc to closed (60%). And has NOT happened since.

I also had 1 log of much lower wgdc then normal during the same logging session above of not reach boost setpoint.... Both extremes same day. But fine now, just with a higher wgdc then expected.

Thanks for any help

[JamesM3M5]

Hey Josh, I honestly don't know what's up with that issue. I have recently replaced a turbo because the WG shaft entering the turbo was badly worn and hanging when the actuator was trying to close the WG. But it was consistent - 100% would not pull the WG closed. If yours is sticking lightly, then the higher WGDC could easily be a result. If it's the front turbo, good luck getting anthing on it to check with the turbo still in the car. I was able to disconnect the actuator rod from the arm on the rear turbo and manipulate it manually. That's how I found that problem.

[Razodo]

James,

Can the wastegate solenoids cause overboost fault code 30FE?
I did the test that Terry at BMS has on the other forum and I get 18" at idle which apparently is too high, can this be causing overboost? Thanks.

[JamesM3M5]

30FE would probably not be from the solenoids. The vacuum between the WGA and solenoid should be about 5inHg at idle and hit 18-20 when trying to build boost. Vacuum between the pump and the WG should be at least 20 inHg whenever the engine is running. But if you see that after the solenoid, it could be one of them is stuck wide open.

[Razodo]

Thanks, by stuck open do you mean the solenoids? If that's the case, should I replace them?

[scflaw]

how hard is it to replace the solenoid and how much should the part cost.

[marv85]

Originally Posted by scflaw

how hard is it to replace the solenoid and how much should the part cost.

Solenoids are easy to replace since they are on top attached to the engine (passenger side). electric plug, a couple of vacuum line and that's it.

they go for 91$ each at Tischer.

it's part number 4:
http://realoem.com/bmw/showparts.do?...75&hg=11&fg=45

[scflaw]

Originally Posted by marv85

Solenoids are easy to replace since they are on top attached to the engine (passenger side). electric plug, a couple of vacuum line and that's it.

they go for 91$ each at Tischer.

it's part number 4:
http://realoem.com/bmw/showparts.do?...75&hg=11&fg=45

Thanks bud, much appreciated.

[marv85]

no problem, gdluck

[bpdef29]

Didn't want to start a new thread for forum neatness purposes, although OP info is pretty unrelated.

My WG % in my logs keeps fluctuating under 5k (from like 30%-70% back and forth), and it's causing boost to rapidly fluctuate (which I can feel). Then at about 5k, the WG % steadies, as does boost. No underboost codes.

I recently did a full vacuum test and the solenoids seemed to be holding vacuum; should I replace them anyways? Car was doing this a few months ago and then I though I fixed it with an adaptation reset and now it's doing it again....

[Evil///M]

Been having the same 'symptoms' except its a 30FE code, and occasionally going into limp mode.
If you monitor WGDC it will sometimes drop to 0. It's completely random. Give it a little bit of gas, the WGDC comes back up, let off the gas it drops to 0.
I'm wondering if replacing the solenoids will solve this problem once and for all.

[Rob335i]

I was getting 30fe overboost changed one solenoid error went away ,got the second one to do but it looks like a pain to get to

[TrollToll]

Originally Posted by Rob335i

I was getting 30fe overboost changed one solenoid error went away ,got the second one to do but it looks like a pain to get to

They're side by side

[Evil///M]

Originally Posted by Rob335i

I was getting 30fe overboost changed one solenoid error went away ,got the second one to do but it looks like a pain to get to

how consistent was your error, and how long has it gone without error so far?

[Rob335i]

you have to take of the coolant tank to get into it i was getting 30fe everytime I went wot been 2 months now with no issues

[Evil///M]

Originally Posted by JamesM3M5

30FE would probably not be from the solenoids. The vacuum between the WGA and solenoid should be about 5inHg at idle and hit 18-20 when trying to build boost. Vacuum between the pump and the WG should be at least 20 inHg whenever the engine is running. But if you see that after the solenoid, it could be one of them is stuck wide open.

So I tested mine today. The Hg between WG and Solenoid was about a steady 18". Hg before each solenoid (between canisters) On both sides were pretty even between 22" and 22.5"

Manifold Hg cold would hang around 10-11" and when warmed up drops down to 19-20"

I noticed a small crack in one of the vac lines near the T connector to the solenoid, so I cut the end off and stuck it back on hoping it would solve the issue. It did not. I'm still getting drops to 0% WGDC at times.