[pwns]

https://datazap.me/u/pwns/target-boo...ata=2-4-5-9-14

Hey guys,

Stock Map 0 2011 E92 N55, only has BMS intake, is not hitting target boost.

From the log, I see that AFR is all over the place - not sure if that's normal during WOT?

I've cleaned the MAF and nothing has changed.

Has anyone experienced this before?

*EDIT*
I notice AFR spikes when I let off gas to change gears - I guess this makes sense to me, but not sure why I'm not hitting target boost? Do you think I have a boost leak, or is there something I'm not seeing on the log?

[CalibratEd]

Did this start happening recently? Have you done any work to the car recently?

Are you able to log wastegate duty cycle as well?

[pwns]

Originally Posted by CalibratEd

Did this start happening recently? Have you done any work to the car recently?

Are you able to log wastegate duty cycle as well?

I have not done any work to the car recently, I’ve only picked this car up 1 month ago.

How would I log wastegate duty cycle?

Thanks

[pwns]

Originally Posted by pwns

I have not done any work to the car recently, I’ve only picked this car up 1 month ago.

How would I log wastegate duty cycle?

Thanks

From the log I see that wastegate duty cycle is in the 40’s at WOT. From my understanding that mean the wastegate is 40% closed? Shouldn’t it be at 100% when WOT?

Would this mean bad wastegate or something?

[SlowE92]

Originally Posted by pwns

From the log I see that wastegate duty cycle is in the 40’s at WOT. From my understanding that mean the wastegate is 40% closed? Shouldn’t it be at 100% when WOT?

Would this mean bad wastegate or something?

Wastegate/boost leak/ solenoids etc.. And you are correct, when wot it should be at or close to 100% but opening half way. Could be a tired wastegate. How many miles on the car?

[pwns]

Originally Posted by SlowE92

Wastegate/boost leak/ solenoids etc.. And you are correct, when wot it should be at or close to 100% but opening half way. Could be a tired wastegate. How many miles on the car?

That's sad to hear. What steps should I take to diagnose?

Car has around 150k km on it, but rebuilt engine 2k km ago...

Rebuilt but reused turbo I guess

[SlowE92]

Originally Posted by pwns

That's sad to hear. What steps should I take to diagnose?

Car has around 150k km on it, but rebuilt engine 2k km ago...

Rebuilt but reused turbo I guess

I would check for boost leaks. Check Your diverters and connection from chargepipe and throttle body and intercooler. It says you're on the stock flash (Stage 0). Have you tried flashing a map and seeing if it changes? (stage 1 or 2)

Edit: change your vacuum lines too.

[pwns]

Originally Posted by SlowE92

I would check for boost leaks. Check Your diverters and connection from chargepipe and throttle body and intercooler. It says you're on the stock flash (Stage 0). Have you tried flashing a map and seeing if it changes? (stage 1 or 2)

Edit: change your vacuum lines too.

I have not because I'm on stock charge pipe, but maybe I can try stage 1 with a small pull safely?

[CalibratEd]

Originally Posted by pwns

I have not done any work to the car recently, I’ve only picked this car up 1 month ago.

How would I log wastegate duty cycle?

Thanks

Sorry I missed the wastegate duty in the log. I was looking over the log on my phone.

[wheela]

Your fuel trims (ltft and stft) are pretty far off. They're positive, so this means your car has to inject more fuel than normal to hit afr targets. Lots of potential causes, but I see you have the BMS intake, I suspect that's at least part of the problem with the trims. Boost leak could also contribute to trims going positive. If it was my car, I'd put the stock intake back on. The BMS intake is known to through MAF readings off (for some people, it's bad enough to throw a code), and I doubt you're getting any gains from it. Getting to stock intake back on will help you understand how much of the fueling issue is due to the BMS intake vs. a boost leak.

The boost is very low and sluggish. For the stock tune (map 0), the wgdc% is limited in the tune to 65%, so you shouldn't ever see more than that on map 0. I'm on MHD stage 2 and 50's / 60' can get me to 16psi in the middle rpm range. In general, it should be higher during spool up than it is once you hit target. Alot of potential causes for this too. I'd check for boost leaks as mentioned, and another culprit could be a bad boost solenoid (bmw calls in the pressure converter), or leaking/crushing vacuum lines between the valve cover and your boost solenoid. Or a leak some where in the vac line to your exhaust flap, as a leak here will reduce the vacuum available for your boost solenoid to close your wastegate flap. Another potential cause could be a failed diverter valve on your turbo - which won't show up on a boost leak test, and won't throw your trims off. This part is hard to get to though, so I'd try to rule the other things I mentioned out first.

It can seem overwhelming, but just start checking through these things 1 by 1 and eventually you'll find the cause. Good luck!

[wheela]

Originally Posted by pwns

From the log I see that wastegate duty cycle is in the 40’s at WOT. From my understanding that mean the wastegate is 40% closed? Shouldn’t it be at 100% when WOT?

Would this mean bad wastegate or something?

This is close, but not quite. wgdc% controls the amount of vacuum sent to the wastegate canister - roughly, 0% wgdc = 0 vacuum sent, 100% wgdc% = 100% vacuum (around 26 in Hg) sent. But wastegate position is different. Without the car running, the wastegate should fully close around 6 in Hg. But with the engine running, exhaust gas pushes against the wastegate flap, which tries to push it open. So the same wgdc% will yield different physical wastegate positions, depending how much exhaust gas is coming out of the engine. Further complicating things, is that as exhaust gas flow through the turbine increases, eventually flow starts to choke, meaning it gets to the point where increasing exhaust pressure will not push any more flow through the turbine. In this case, you need the wastegate to flow the extra exhaust flow. There are maps in the DME that model these relationships. When you start modifying the engine, the maps no longer accurately reflect what's happening. Here's a screenshot from Garret showing the turbine choking I'm talking about. You can see as pressure across the turbine increases (the x axis), the flow through the turbine starts to choke out, so you stop getting more flow through the turbine, even as pressure is increased.

[pwns]

Originally Posted by wheela

Your fuel trims (ltft and stft) are pretty far off. They're positive, so this means your car has to inject more fuel than normal to hit afr targets. Lots of potential causes, but I see you have the BMS intake, I suspect that's at least part of the problem with the trims. Boost leak could also contribute to trims going positive. If it was my car, I'd put the stock intake back on. The BMS intake is known to through MAF readings off (for some people, it's bad enough to throw a code), and I doubt you're getting any gains from it. Getting to stock intake back on will help you understand how much of the fueling issue is due to the BMS intake vs. a boost leak.

The boost is very low and sluggish. For the stock tune (map 0), the wgdc% is limited in the tune to 65%, so you shouldn't ever see more than that on map 0. I'm on MHD stage 2 and 50's / 60' can get me to 16psi in the middle rpm range. In general, it should be higher during spool up than it is once you hit target. Alot of potential causes for this too. I'd check for boost leaks as mentioned, and another culprit could be a bad boost solenoid (bmw calls in the pressure converter), or leaking/crushing vacuum lines between the valve cover and your boost solenoid. Or a leak some where in the vac line to your exhaust flap, as a leak here will reduce the vacuum available for your boost solenoid to close your wastegate flap. Another potential cause could be a failed diverter valve on your turbo - which won't show up on a boost leak test, and won't throw your trims off. This part is hard to get to though, so I'd try to rule the other things I mentioned out first.

It can seem overwhelming, but just start checking through these things 1 by 1 and eventually you'll find the cause. Good luck!

Wow thanks for all the info! I plan on building a DIY smoke tester today and start there. Hopefully I find the issue with that rather than it being a turbo issue.

I'm also looking for a stock air intake - because car came with BMS one.

I'm getting lean code 2BC0, hopefully that's just the BMS intake..

[pwns]

Originally Posted by wheela

This is close, but not quite. wgdc% controls the amount of vacuum sent to the wastegate canister - roughly, 0% wgdc = 0 vacuum sent, 100% wgdc% = 100% vacuum (around 26 in Hg) sent. But wastegate position is different. Without the car running, the wastegate should fully close around 6 in Hg. But with the engine running, exhaust gas pushes against the wastegate flap, which tries to push it open. So the same wgdc% will yield different physical wastegate positions, depending how much exhaust gas is coming out of the engine. Further complicating things, is that as exhaust gas flow through the turbine increases, eventually flow starts to choke, meaning it gets to the point where increasing exhaust pressure will not push any more flow through the turbine. In this case, you need the wastegate to flow the extra exhaust flow. There are maps in the DME that model these relationships. When you start modifying the engine, the maps no longer accurately reflect what's happening. Here's a screenshot from Garret showing the turbine choking I'm talking about. You can see as pressure across the turbine increases (the x axis), the flow through the turbine starts to choke out, so you stop getting more flow through the turbine, even as pressure is increased.

Very interesting read. Never knew wastegates were this complicated.

Always thought WOT=closed - PSI target reached = open

I'll be posting updates on this problem I have.

Thanks!

[pwns]

So I made a DIY vacuum leak smoke tester.

The pipe in the picture is what is leaking for the connection. not sure if its a gasket/O-Ring or if the pipe needs to be replaced. But the smoke was coming right from the connection..

If I need a new pipe - which pipe do I replace?

[pwns]

Right where the arrow is to be clear.. What should my next steps be? I was planning on getting a VRSF charge pipe as well.

[fastboatster]

this is on the inlet size of the turbo, not on the charge pipe side, the pipe is not exposed to boost pressure and doesn't crack. just replace that gasket, it allows unmetered air into the system, and MAF sensor and speed density (map sensor-based) airflow readings become inconsistent with each other. so you have a vacuum leak which explains wild afr readings. I had that gasket leak and had some driveability issues

[pwns]

Originally Posted by fastboatster

this is on the inlet size of the turbo, not on the charge pipe side, the pipe is not exposed to boost pressure and doesn't crack. just replace that gasket, it allows unmetered air into the system, and MAF sensor and speed density (map sensor-based) airflow readings become inconsistent with each other. so you have a vacuum leak which explains wild afr readings. I had that gasket leak and had some driveability issues

I see, thank you for the info.

Would you have a part number or link to that exact gasket? I'm not 100% sure which gasket it is.

I hope that's my whole boost leak issue

[wheela]

Originally Posted by pwns

I see, thank you for the info.

Would you have a part number or link to that exact gasket? I'm not 100% sure which gasket it is.

I hope that's my whole boost leak issue

It's #29 in the drawing, here's a link.

https://www.fcpeuro.com/products/bmw-gasket-13717599292

That will help with the fuel trims/lean code, but not the boost issue. Since you didn't find any other leaks, I'd look into the boost solenoid, or vac lines for the boost solenoid & exhaust flap next.

[pwns]

Originally Posted by wheela

It's #29 in the drawing, here's a link.

https://www.fcpeuro.com/products/bmw-gasket-13717599292

That will help with the fuel trims/lean code, but not the boost issue. Since you didn't find any other leaks, I'd look into the boost solenoid, or vac lines for the boost solenoid & exhaust flap next.

You don’t think that’ll fix the boost leak due to it being the turbo inlet pipe? And is the boost solenoid also referred to as the pressure converter? - I've seen many posts about that.

This one:
https://www.fcpeuro.com/products/bmw...er-11747626351

[wheela]

Originally Posted by pwns

You don’t think that’ll fix the boost leak due to it being the turbo inlet pipe? And is the boost solenoid also referred to as the pressure converter? - I've seen many posts about that.

This one:
https://www.fcpeuro.com/products/bmw...er-11747626351

Fixing the leak at your intake pipe will definately be a good thing to do but it won't help out the boost issue. Since the leak is on the low pressure side of the compressor, it only leaks unmetered air in after your MAF sensor - more strongly under boost as that's when vacuum is highest in that part of the plumbing. Hopefully it will resolve your lean code, and fuel trims, but tough to say for sure with the BMS intake.

Yep, what BMW calls the pressure converter is what people casually refer to as the boost solenoid.

Does your car by chance have an after market exhaust? If so, it's critical the vacuum line for the exhaust flap (for the oem muffler) is plugged, as both the wastegate and exhaust flap vacuum lines are connected to the same vacuum reservior & vac pump. So if your exhaust flap line is open or leaking somewhere, that reduces the vacuum available for your boost solenoid to pull your wastegate closed and make boost.

[OMEGA412]

Check your whole charged air system for any leaks, start at your turbo outlet into the intercooler than your charge pipe and intake manifold, most likely one of these parts is leaking leading to your boost leak. The weird AFRs and everything else is most likely due to the boost leak.

[pwns]

Originally Posted by OMEGA412

Check your whole charged air system for any leaks, start at your turbo outlet into the intercooler than your charge pipe and intake manifold, most likely one of these parts is leaking leading to your boost leak. The weird AFRs and everything else is most likely due to the boost leak.

Originally Posted by wheela

Fixing the leak at your intake pipe will definately be a good thing to do but it won't help out the boost issue. Since the leak is on the low pressure side of the compressor, it only leaks unmetered air in after your MAF sensor - more strongly under boost as that's when vacuum is highest in that part of the plumbing. Hopefully it will resolve your lean code, and fuel trims, but tough to say for sure with the BMS intake.

Yep, what BMW calls the pressure converter is what people casually refer to as the boost solenoid.

Does your car by chance have an after market exhaust? If so, it's critical the vacuum line for the exhaust flap (for the oem muffler) is plugged, as both the wastegate and exhaust flap vacuum lines are connected to the same vacuum reservior & vac pump. So if your exhaust flap line is open or leaking somewhere, that reduces the vacuum available for your boost solenoid to pull your wastegate closed and make boost.

UPDATE:

Sad day today. I ordered that gasket and it was the wrong one - smaller in diameter unfortunately.

While I was down there, I noticed another pipe that is very damaged (see image). Smoke could have been coming from there during my smoke test as well, but maybe I didn't notice since its right below the other leak.

Is the cracked part this?:
https://www.ecstuning.com/b-vrsf-par...10901020e~vrf/

*EDIT*
sorry the pictures are massive - I don't think I can resize them here lol