[grizzjr1]

Originally Posted by DozerDan82

Yes it is, does anyone know how it is supposed to function as far as vac/free flowing?

I believe vacuum is applied at about 3500-4000 rpms or so. This bypasses the small turbos compressor. It is an on/off rather than variable pressure switch.

After 2 weeks of figuring out exactly how this whole system works, running vacuum gauges while driving on the lines, and lots of other fun diagnostics, I can finally say I think I understand it all! I purchased two new pressure converters, took apart one old to see how it worked and was pretty disappointed when I had a half of a converter arrive in the mail One came just fine and worked great, but the other was missing the top where the vacuum lines plug in! I ended up managing to temporarily repair the one I took apart, but I can tell its not functioning at 100 percent.

[OmahaDZL]

lor3n...

Yes that makes sense....but if you havent gutted your cat yet...thats the problem.... thats what happened to mine...

I got Bohls downpipe, got stage 3 and was waiting for the new exhaust kits to come on the boat...in the unknown amount of miles between, I fried my exhaust pressure sensor. ....so I couldnt wait any longer...so I took out my exhaust and gutted the cat..... problem solved... You may want to order exhaust from someone

[lor3n]

Originally Posted by OmahaDZL

lor3n...

Yes that makes sense....but if you havent gutted your cat yet...thats the problem.... thats what happened to mine...

I got Bohls downpipe, got stage 3 and was waiting for the new exhaust kits to come on the boat...in the unknown amount of miles between, I fried my exhaust pressure sensor. ....so I couldnt wait any longer...so I took out my exhaust and gutted the cat..... problem solved... You may want to order exhaust from someone

I got a full exhaust from eBay and Jess made a custom mid pipe to hook the 335i exhaust into the down pipe. I didn't run the downpipes and tune for more than a few weeks before i put the mid pipe and the rest of the exhaust on.

[lor3n]

So… I was trying to pull the vacuum hose from the EGR connector and busted of the nipple. I am basically swapping the electric changeover valve from the EGR to the compressor bypass valve to see if that fixes my issue with lack of boost at low RPM. Since I have my EGR deleted in my tune to I need to fix that broken nipple on the vacuum connector of the EGR or can I plug that hose and call it good?

[OmahaDZL]

Originally Posted by lor3n

I got a full exhaust from eBay and Jess made a custom mid pipe to hook the 335i exhaust into the down pipe. I didn't run the downpipes and tune for more than a few weeks before i put the mid pipe and the rest of the exhaust on.

I probably drove mine for a month or so before it happened...sooo...no guarantees....but if you are saying you dont have a cat, then you obviously should be good and maybe that thing just burns out now and again...

Just sounds so eerily familiar...

[grizzjr1]

Originally Posted by lor3n

So… I was trying to pull the vacuum hose from the EGR connector and busted of the nipple. I am basically swapping the electric changeover valve from the EGR to the compressor bypass valve to see if that fixes my issue with lack of boost at low RPM. Since I have my EGR deleted in my tune to I need to fix that broken nipple on the vacuum connector of the EGR or can I plug that hose and call it good?

If it's actually deleted then it should not matter, vacuum wouldn't be applied to that actuator at any time.

[lor3n]

Originally Posted by grizzjr1

If it's actually deleted then it should not matter, vacuum wouldn't be applied to that actuator at any time.

Ok perfect. I plugged the hose and took it out for a test drive after swapping the two electric changeover valves between the EGR and the compressor bypass valve control and for the first few minutes I thought my car was still having the same issue but the the small turbo started working like it was supposed to. I am going to take it out for another test and see how she drives. Thanks for all the help everyone and I hope this is the end of this story for now… fingers are crossed.

[lor3n]

Originally Posted by OmahaDZL

I probably drove mine for a month or so before it happened...sooo...no guarantees....but if you are saying you dont have a cat, then you obviously should be good and maybe that thing just burns out now and again...

Just sounds so eerily familiar...

Yeah I think that it would have been from either running the down pipe prior to getting the mid pipe etc or from the DPF problem before. I don't know if it make any difference in how the car runs though. Did you replace your sensor? I think on mine the pipe may have been leaking exhaust where the host clamps to the sensor, I tightened it when I gutted my car the first time just to see if that would make any difference.

[grizzjr1]

Originally Posted by lor3n

Ok perfect. I plugged the hose and took it out for a test drive after swapping the two electric changeover valves between the EGR and the compressor bypass valve control and for the first few minutes I thought my car was still having the same issue but the the small turbo started working like it was supposed to. I am going to take it out for another test and see how she drives. Thanks for all the help everyone and I hope this is the end of this story for now… fingers are crossed.

Good to hear! Keep testing it though, you should have absolutely no vacuum being pulled at idle going to the compressor bypass control. If there is some it is closing partially which is killing the small turbo. I had a combo of a lot of issues happening. My pressure converter for my big turbo wastegate control was iffy at best and would leave the wastegate open too far, releasing pressure. The biggest issue was my exhaust changeover valve pressure converter varying wildly, which would snap shut briefly and the high pressure turbo would yell at me. Very scary. That combined with my compressor bypass valve leaking put a lot of pressure on the high pressure turbo. I'm hoping nothing is ruined

[Yozh]

Originally Posted by lor3n

That makes sense, I'm no expert so when you say to see if it holds vacuum you mean to use the pump to add pressure and see if the pressure stays constant?

You would be pulling vaccum not adding pressure to test it.

Your exhaust pressure sensor looks quite sooty. I would replace it along with the feed tube and the banjo bolt with two washers.

[Yozh]

Originally Posted by DozerDan82

Question though.

The red vacuum line, from front to back, is that supposed to hold vac? Mine does not, but if I pull vac on the front canister it goes to it holds. I can also blow air freely through the red line (front to back) I am assuming it does not do anything until it is activated?

Yeah, it's normal. What is supposed to hold the vacuum is the input to the EUV, you were blowing into the output that red hose hooks up. The actual vacuum actuators/canisters suppose to hold vacuum.

[OmahaDZL]

As always...Yozh come in like a specialist contractor to set everyone straight....

Thanks Yozh.

BTW...I think Im all at 100 right now.... no CELs, car is running strong and clean...barking tires all over the place (sometimes its tough to start out from a light without spinning one) Thanks for ALL your help sir...this thread was what fixed the biggest issues with my car.

[lor3n]

Originally Posted by Yozh

And finally, for lor3n. Having ran with an elevated exhaust pressure also may have affected your O2 sensor. 4 bar (58psi) is max per spec. I think we are seeing way over 50psi at high fuelling. If you do replace it, mean quantity adaptations should be reset.
Attachment 1565781

It seems like my car is still having the same issues after all. I am going to test the vaccuum system for leaks. How would I reset the mean quantity adaptations?

[grizzjr1]

Originally Posted by Yozh

Yeah, it's normal. What is supposed to hold the vacuum is the input to the EUV, you were blowing into the output that red hose hooks up. The actual vacuum actuators/canisters suppose to hold vacuum.



I can't keep up with all the recent replies in this thread. But you guys are confusing eachother, so it seems, by mixing the turbo switchover with the compressor bypass. I think the info posted at the start of this thread explains the functions of both.

Just to comment on this: There is full vacuum applied from the system at the EUV (electric changeover valve) that controls the compressor bypass. The EUV is not energized and is therefore closed. As such no vacuum pulls through the "red" hose that is connected to the compressor bypass vacuum actuator that controls the actual mechanical flap. Normally, the mechanical flap is closed when no vacuum is applied. When it opens, it does not close the HP (small turbo) side, that one is always open, it just opens the air side from the LP (big turbo). Look at the last two images posted. If your EUV is leaking, it may or not actuate (partially) the compressor bypass flap. Even if the flap is actuated, (remember, this is on the air side, not exhaust) it will will bleed boost generated by the HP (small) turbo towards the LP (large) turbo instead of the intercooler. Testing the EUV is easy. It has to hold vaccum applied at the input nipple (the one pointing straight up, not to the side), has to have a resistance of 14ohm (i think i remember that correctly), and finally, you can apply 12v to it to make sure it works, simple on/off. Compressor bypass is actuated at about 3200rpm. You can actually test it in action if you tee-off an extra vacuum line from the red line (easiest just off the connection to the vacuum actuator/canister, route it to the car, hook to the vacuum gauge and watch it as you drive. It would show full vacuum after about 3200 rpm, if you actually have boost. No boost, no switch. Same can be done to the turbine switchover and wastegate.

Here is some more info on the compressor bypass:

Attachment 1565776

Attachment 1565777

Attachment 1565778

Attachment 1565779


Couple of more notes. Never pull vacuum lines off the plastic nipples. Use a fine exacto-knife and cut them carefully, to split. Yes, you would have to replace them then. Probably time for most anyway.

Low rpm boost issues could be many. But compressor bypass control is not usually it. Leaking EUV, could be it along with other vacuum leaks. But I would look at exhaust pressure (elevated, or your sensor and it's associated leaking, possibly, feed tube), boost leaks (red boost hose, intercooler connections, cold side, EGR connection) and of course the turbine switchover control.

Having to take that rats nest apart vay too many times, I would suggest to anyone digging in there to do a few things. If you have some mileage on your ride, get two new pressure converters, they are cheap from ECS (by Kaiser ones at $60 a pop), get new vacuum lines. Learn how to test vacuum actuators and EUVs. Replace anything with broken plastic nipples (eg.: vacuum accumulator (that black thing) box). Dig in there and replace all the lines and pressure converters once. Too painful to do it again and no worth the $60 you have to spend the next time. Also, understand, that your vacuum gauge will not show small leaks, sometimes you need to hear them out (happened with my wastegate pressure converter - worked perfectly, system vacuum ok, but I heard it hissing when I was testing with a tee-off extra line in the car, so replaced it.)

Also, understand that vacuum system is a closed loop thing. Any other leaks can affect your turbo control. For example a leaking engine mount will reduce system vacuum overall and will affect how your turbo switchover functions. Test the rest of the components, it's fairly easy if you got to this stage.

And finally, for lor3n. Having ran with an elevated exhaust pressure also may have affected your O2 sensor. 4 bar (58psi) is max per spec. I think we are seeing way over 50psi at high fuelling. If you do replace it, mean quantity adaptations should be reset.

Attachment 1565781

Ahhh thank you Yozh. I think we did confuse each other. I was trying to state that my UEV was leaking vacuum to the changeover valve. On top of that BOTH pressure converters were sticking, causing a lot of issues. The exhaust changeover valve would vary wildly sticking open then slamming shut. My wastegate was doing the same. It was hard to tell on a vacuum gauge because the valves must operate so quickly. You could easily tell when the valve was full open (0 inHg) and full closed (27 inHg), but when it would be in the process of opening (assuming sticking) it would jump around. My turbos were making sad noises. I pulled the piping off to check for play and there wasn't any, so that's good.

That all being said, I just picked up my second pressure converter from BMW and all is well! I replaced every vacuum line while I was in there. This thread helped me a ton!

[grizzjr1]

Well... both converters replaced, all vacuum lines replaced, vacuum pump pulling ~27-28 inHg, swapped maf with my other 335D, and it looks like my issue is still there. It seems as though my exhaust changeover valve is pulsating then slamming shut on upshift on occasion? I'm not certain really. It seems to only happen when the car is cold. I took a video, dropped my daughter off at her grandparents and left the car running while I was inside, and now it is working fine on my way to work. This is what I recorded. If you listen closely, you can hear a pff, pff, pff then when it shifts the turbo barks. I have a. 12V big turbo Cummins that runs over 60 psi and it sounds similar to when that turbo barks.

Let me know what you guys think. It does this then functions perfectly fine, the changeover valve moves freely by hand. I applied vacuum to the valve and it held pressure just fine, as well as actuating every time vacuum is applied.

The high pressure turbo just stopped working completely and went back to normal after a quick pass. Hmm. What gives? Any feedback is certainly appreciated typing on mobile so sorry if this is some poor formatting

[Yozh]

Originally Posted by grizzjr1

Well... both converters replaced, all vacuum lines replaced, vacuum pump pulling ~27-28 inHg, swapped maf with my other 335D, and it looks like my issue is still there. It seems as though my exhaust changeover valve is pulsating then slamming shut on upshift on occasion? I'm not certain really. It seems to only happen when the car is cold. I took a video, dropped my daughter off at her grandparents and left the car running while I was inside, and now it is working fine on my way to work. This is what I recorded. If you listen closely, you can hear a pff, pff, pff then when it shifts the turbo barks. I have a. 12V big turbo Cummins that runs over 60 psi and it sounds similar to when that turbo barks.

Let me know what you guys think. It does this then functions perfectly fine, the changeover valve moves freely by hand. I applied vacuum to the valve and it held pressure just fine, as well as actuating every time vacuum is applied.

The high pressure turbo just stopped working completely and went back to normal after a quick pass. Hmm. What gives? Any feedback is certainly appreciated typing on mobile so sorry if this is some poor formatting

Originally Posted by Yozh

That video has a lot of ambient noise. I tried listening through nice earphones and still can not pinpoint what noise that you are referring to. Perhaps, you can post what time in the video that we should pay attention to.

Couple of other thoughts.
-do you have diagnostic software and/or tools, sorry if you had mentioned anything before;
-when was the last time you changed the fuel filter?
-have you considered running a parallel vacuum gauge to the output of the turbo switchover pressure converter to see how vacuum behaves?

^^^ From your other thread^^^

Also:
-Does your system vacuum fluctuates or stays constant at 28inHg?
-If this happens only when car is cold. Please describe how cold. First couple of minutes after start, or until car is at the full operating temperature?

[grizzjr1]

Originally Posted by Yozh

I have texted a friend who is running Malone on his D and hopefully he will chime in.



That video has a lot of ambient noise. I tried listening through nice earphones and still can not pinpoint what noise that you are referring to. Perhaps, you can post what time in the video that we should pay attention to.

Couple of other thoughts.
-do you have diagnostic software and/or tools, sorry if you had mentioned anything before;
-when was the last time you changed the fuel filter?
-have you considered running a parallel vacuum gauge to the output of the turbo switchover pressure converter to see how vacuum behaves?

Originally Posted by Yozh

^^^ From your other thread^^^

Also:
-Does your system vacuum fluctuates or stays constant at 28inHg?
-If this happens only when car is cold. Please describe how cold. First couple of minutes after start, or until car is at the full operating temperature?

Since this is mainly turbo related, I'll continue the chat about it here.

In the video, the surging chh chh chh starts at about 5 seconds and lasts until about 10 seconds. The larger surge that sounds like the small turbo barking (to me at least) is at about 12 seconds. After this point I temporarily lost high pressure turbo for about 30 seconds then it started somewhat functioning again.

It is acting like it's pulsating, so you have peaked my interest in the supply side. I have a BavTech cable, but when I go to record engine parameters, the options are all in German. I also have a Bluetooth obd2 and an android phone dedicated to it. The refresh rate is slow on it, but I will attempt to record some data. I changed the fuel filter this last week, flushed the filter using BavTech and primed the system.

I have a vacuum gauge I use for setting idle fuel rates on carb'd vehicles. I tee'd off a line and have monitored both of the pressure converters actions, but that was before installation of my most recent one. Granted, it worked for a day and then started acting up. I know my charge air temp sensor is bad, and I have a new one in the box but I haven't installed it yet. I assume it isn't vital enough to cause this issue. The vacuum gauge acted like the turbo would stick either open or shut, it didn't have much play in between.

Yesterday I was manually actuating the exhaust side turbo changeover, i was able to actuate it back and forth easily by hand and by attaching a vacuum line to it while applying pressure manually. I am going to go Over my vacuum lines yet again this morning. I have not touched the engine mount lines, in curious as it if they are an issue? I will also monitor the support side with the engine running at various rpms. I have only tested it at idle.

[Yozh]

Thanks for the time references, makes more sense now. Interesting that 'barking' comes on at around 3k rpm. Is it possible that it is all of the same sound that gets amplified at higher boost, may be a boost leak? Have you checked for those? I would definitely suggest pulling some data from the car. Boost, MAF, etc. If you have a spare IAT sensor, install it. It has a relationship to the MAF and Boost sensor. But then, do you think yours have failed?

[grizzjr1]

Originally Posted by Yozh

Thanks for the time references, makes more sense now. Interesting that 'barking' comes on at around 3k rpm. Is it possible that it is all of the same sound that gets amplified at higher boost, may be a boost leak? Have you checked for those? I would definitely suggest pulling some data from the car. Boost, MAF, etc. If you have a spare IAT sensor, install it. It has a relationship to the MAF and Boost sensor. But then, do you think yours have failed?

Alright, so, last night I was comparing the vacuum lines that I put on my car versus the lines I ran on the wifeys. I'm pretty sure mine were a size larger than I had asked for at O'Wronglys. It would make sense why boost issues were more prevalent on colder days and when the car isn't warmed up because the hose wasn't able to get a good seal. I changed everything out to smaller line I had laying around, and will be ordering proper sized 3.5mm silicone lines off off Amazon today. I received my IAT sensor in the mail so I will toss that in when I have time. I started the car this morning, let her warm up for a few minutes while setting up TorquePro, and headed off. Right off the gate coolant temp was about 105 F (hadn't started logging yet), I pulled out of my driveway and was greeted with that turbo bark and flutter. I watched boost pressure climb rapidly, but not go over about 15-16 psi. My exhaust back pressures jumped horrendously when I gave her some fuel. I assume the valve was stuck shut at this point. Within 30 seconds the car started acting perfectly normal, and continued to do so my entire 45 mile commute. Better than how has been going; with it working for a few minutes, then acting up, and back again to working fine.

I began logging data after hopping on the interstate about 2 miles from my house. I had to set up what I would like to log yet when it was acting up. I began logging, and parameters looked pretty normal. MAF, boost, and exhaust pressure followed similar curves, I could tell it was running strong. There is no boost leaks, I tried testing the system by capping it off. One thing a little off is my boost pressures. It peaked and heald at about 33-34 psi on a 70-110 run. Is there something up with my wastegate? I mean it ran flawlessly and very strong. Now I'm beginning to question what all is actually done with my car... I purchased it from a dealer (albeit probably not the best one around) and they knew no history on the car. A gamble, but I got the car for a steal knowing it had some issues. I installed a JBD and run it at 100 percent. It's quick. Probably quicker than it should be. Swirl flaps were already installed, as well as a few other modifications. I did an EGR block, but noticed today in torque I never saw any EGR requested. So..... maybe I am tuned? And accidentally stacking a JBD on top. Well then...

[Yozh]

Posted a reply in your other thread:
http://www.e90post.com/forums/showth...1349691&page=2

[Yozh]

Thought I would re-post this here from the Log Requests thread.

On my drive to work on Friday I have played with some parameters. Here are a few interesting ones that may be useful with diagnosing some of the vacuum turbo control system. By this I mean that one can monitor the DDE requests to the actual vacuum output of the controllers and also see how fast they react. I have done this experiment on a compressor bypass where DDE switches the EUV valve within fraction of a second and the vacuum response was instantaneous as well.

[TDIwyse]

Outstanding contribution. Thank you.