[VladPC]

I fixed it! Thank you all!!!

All in all there were two problems :

1) A small piece of vacuum hose somewhere near the electric valve which controls the bypass valve (this vacuum hose was replaced a while ago...last autumn I think). It fixed it in a way that it had power from 2500 rpms. Before it was nothing untill 3000 rpms.

2) Bad adjustment of the turbine changeover rod (which I just set it to 16 or 17 threads...can't remember right now)

Now the car has full torque at about 1700rpm...exactly how it is specified on all repair manuals, diesel technology pdf files and so on...you know what I'm talking about.
Though the car pulls like hell from 1200-1300 rpms but does not have full torque...I might tighten a bit the little nut to more than 16 threads but for now is perfect!

Again thank you all for everything, my friends!

[RL18]

Glad it worked for you

[robnitro]

Is there a spec for that actuator, vacuum at which if starts to move and vacuum at when it finishes travel? That would be the best way to calibrate them, like on the tdi vnt15/17s start movement at 4-6" and end at 18-20" for example...

Otherwise we are just adjusting by sight and vlad you could go too short and cause dangerous turbo spikes at low rpm

[abha]

Hello all, I know this is an old thread, sorry to revive...but this is the most complete thread that I think will benefit from a place to check that I have never seen posted.

Anyways, I have a 335d deleted, malone 2.9, hybrid turbos, entire exhaust from downpipe back straight, ATM intake etc, etc, etc.

I had the exact same problem as all of you. Essentially small turbo not holding boost, sometimes goodish, sometimes non-existent.

I changed my vacuum lines (all multiple times w/ multiple different brands of silicone), actuators, EV valves (all), valve cover gasket, the three O rings in the vacuum pump (including the internal one that BMW doesn't sell), main vacuum pipe hose off the vacuum pump (turned to plastic and cracked), main vacuum pipe/distributor pipe under the intake, MAF sensor, MAP sensor, break booster hose, break booster check valve/gasket, small turbo, large turbo, intercooler hoses (upgraded), ASV hose (ATM upgrade), glow plugs, glow plug controller, intake gaskets, vacuum reservoir, probably replaced other odds and ends that are listed in euro blogs.

Checked vacuum and would hold ~15-20 mmHg while running, some times would lose vacuum at shutoff immediately, sometimes wouldn't. Checked that turbine bypass was holding vacuum and moving, adjusted the actuator as Newtis describes, checked that vacuum compressor bypass and wastegate working.

All to no avail.

This weekend I was about to buy and replace the vacuum pump (last option)... and I finally found the source. It wasn't the vacuum pump. I just decided to remove the black coupler from the vacuum pump that connects to the rubber hose/vacuum pipe and noticed an orange gasket. There is a little dot that appeared off center.

Went online, noticed no one ever wrote about this damn connection other than replacing the O-ring. Also noticed that BMW doesn't sell the black coupler.

Anyways, decide to mess with it, blow on it from both sides and air passes through...thought that was weird considering an orange rubber piece is in the middle.

Discover that it can be taken apart easily. Removed the friction grip black circular piece discover a spring, remove that, and then remove the orange rubber diaphragm. I discover two plasticized black pieces of old hose under the diaphragm that has not been allowing it to seal. Remove those. Put it back together in reverse, blow on it, and it now seals.

Put it back in car, everything works. Small turbo spools perfectly on startup, maintains boost in low RPM through the entire range. Tires break loose immediately on acceleration...fun again. Get 45 freeway mpg again (up from 27 mpg).

Anyways. Just wanted to let people know to check that spot as it is literally a 5 minute job. Ill post pics in a bit.

Sorry to bring an old thread alive again...but for think it would be a beneficial addition if anyone is chasing a vacuum leak still

Last pic shows the small plastic piece that was there (next to the torx wrench)

[lnxguy]

Great info! I didn't even think about this stupid piece after swapping my vac pump (For a completely different reason)

[maryjane]

NICE FIND!

[335dzlll]

I have the same case of no boost till 3k rpms. My 335d is at the shop and as of yesterday recieved a full ABC soup delete, new vacuum pump o-rings, thermostat.

The mechanic also checked the pressure converters and all the vacuum lines which are all fine, and by his words theres no vacuum leaks which i believe is true as I also vacuum pump tested everything from the middle of the engine to the passenger/turbo control side.

He sent me a video of the cold start after the delete and i can vaguely hear the small turbo whistle, which is usually obnoxious on these cars, that and other reasons lead him to believe the culprit is the small turbo(HP) thats gone bad.

Is there anything else i should have him check before i take the car back?

[nonford]

Depending on your miles, and when the last time it was replaced....valve cover gasket. Once you introduce more power, weaknesses will be exposed....the turbos on these these things are pretty stout. You mentioned hearing the whistle, thats your small turbo singing after the delete. To me it would indicate its spinning...It doesnt take much to pull it off and inspect the small turbo. Good luck..

[335dlci]

I do offer turbo rebuild services.

[maryjane]

There are quite a few tests you can do to narrow down the issue. PM me if you'd like some guidance.