N54 Wastegate 0% duty cycle

[iDontRemember]

Update: the wgdc dropping seems to coincide with target boost being abnormally low. What perameters does the DME use to set target boost?

https://datazap.me/u/idontremember/k...zoom=1124-2631

I’m at a loss, and it probably doesn’t help that this is my 1st BMW. Learning this platform has been trying at times.

That said, my WGDC drops to 0% on partial load, if I give it more throttle it will slowly build boost but doesn’t hold, never reaches peak and tapers off very quickly.

WG control solenoids are working as intended, no vacuum leaks. A very minor VC leak but no pooling in the injector or plug bores. No boost leaks, I’ve smoke abs pressure tested.

I’ve had a mild misfire, nothing I thought was too serious, just a light hiccup but, I’ve notice the misfire count no longer increases on my monitoring software. I’m leaning towards leaky/sticking injectors at this point.

I’ve seen a few mentions of cylinder individual lambda control (CILC) but, being that this is beyond my current knowledge, I’m unsure how to test for/ monitor it.

Not a lot of info out there with my exact problem but if any N54 gurus have some knowledge they’d like to share, I’d be grateful.

Thanks 😊

[ShocknAwe]

Wgdc floor should be around 10% or so. Do you have rattle? Wonder if your actuators are sticking.

[iDontRemember]

Originally Posted by ShocknAwe

Wgdc floor should be around 10% or so. Do you have rattle? Wonder if your actuators are sticking.

No rattle, actuators work when I manuall apply vacuum but, if they were sticking, I should see more than 10%. At a gradual throttle tip in, WGDC goes from 50% and drops to 0% with more throttle. So it acts like a N/A car instead of boost building.

[ShocknAwe]

Ok not sticking full open then. Vac leak or old lines are collapsing. I know you tested it but it's broken somewhere. Perhaps the canisters have a crack.

I imagine if your lines were all fine and it was the pump instead you'd have other issues.

Cheap test is replace every piece of vacuum line, it's about $20 for a spool.

Are the lines going to your diverters or BOV intact?

[wheela]

Are you having any codes? Are you logging and seeing 0% wgdc, or assuming it's zero because you have no boost? I agree with ShocknAwe, except I don't understand how those things would make your wgdc% go to 0%? Unless the car turns off boost control because you're under boosting so bad, but there should be codes if that's the case, no?

[ShocknAwe]

Originally Posted by wheela

Are you having any codes? Are you logging and seeing 0% wgdc, or assuming it's zero because you have no boost? I agree with ShocknAwe, except I don't understand how those things would make your wgdc% go to 0%? Unless the car turns off boost control because you're under boosting so bad, but there should be codes if that's the case, no?

Agreed with the above.

[iDontRemember]

Originally Posted by ShocknAwe

Agreed with the above.

Originally Posted by wheela

Are you having any codes? Are you logging and seeing 0% wgdc, or assuming it's zero because you have no boost? I agree with ShocknAwe, except I don't understand how those things would make your wgdc% go to 0%? Unless the car turns off boost control because you're under boosting so bad, but there should be codes if that's the case, no?

Logging and seeing 0% duty. Vac lines have been tested and are good. I can manually actuate the WG with vac pump. No codes present. Not tuned & mostly stock.

[iDontRemember]

Originally Posted by iDontRemember

Logging and seeing 0% duty. Vac lines have been tested and are good. I can manually actuate the WG with vac pump. No codes present. Not tuned & mostly stock.

Unfortunately for me, I’ve had this car for 5 years and it’s never given me any problems so I’ve not had the opportunity to learn the platform well.

New vac lines installed. Old ones were in surprisingly good shape. Fix a couple of very very minor leaks via smoke detection. I put my hands on the rear WG and it’s got some minor play but is definitely functional at this point. Even if it wasn’t, that wouldn’t explain fuel trims and 0% duty cycle.

Lean on both banks, adding 10-15% at idle. The VC has developed a small ooze but doesn’t really leak so I’ve been putting it off. Is it possible that the VC has a vac leak that I can’t find with a smoke machine? Just trying to think what would effect both banks.

[iDontRemember]

The target boost is low!

What would cause the DME to set it so low?

https://datazap.me/u/idontremember/k...=0&data=1-3-22

[ShocknAwe]

JB4?

[iDontRemember]

Originally Posted by ShocknAwe

JB4?

Stock aside from a catch can and midpipe.

[ShocknAwe]

So I'm not seeing the zero wgdc. If anything it's higher than it should be for your throttle position. Can you do a WOT run?

What's the car sound like?

[iDontRemember]

Originally Posted by ShocknAwe

So I'm not seeing the zero wgdc. If anything it's higher than it should be for your throttle position. Can you do a WOT run?

What's the car sound like?

The car sounds okay until WGDC drops and opens the wastegate all the way. Aside from the weird wastegate issue, it runs great, doesn’t consume much oil (1/2qt over 4K miles). Fuel consumption is still decent (average 20-21 mixed driving)

Here’s one where the wgdc drops to zero. Apologies if my logs suck, I haven’t had to log data in more than 15 years and I’m having to relearn what’s what.

https://datazap.me/u/idontremember/l...zoom=5934-6271

[ShocknAwe]

Have you ever had a 30FF?

Do any maintenance recently esp possibly MAP sensors? Still have stock diverter valves?

I think you're effectively going into a safety/limp due to maybe a boost leak, wgdc correction is timing out due to underboost.

[iDontRemember]

Originally Posted by ShocknAwe

Have you ever had a 30FF?

Do any maintenance recently esp possibly MAP sensors? Still have stock diverter valves?

I think you're effectively going into a safety/limp due to maybe a boost leak, wgdc correction is timing out due to underboost.

No codes that are DME related. ( the only code I have is a random lost communication to the ABS that comes ana goes).

Coils, plugs, belt and pullies, air cleaner. Just basic stuff. I had aftermarket valves and charge pile but put it all back to stock to eliminate all possibilities. I had a spare pressure sensor for the manifold, put that in today and I’ll do the same with the charge pipe tomorrow if I get a chance. I can’t find anything that’s disconnected anywhere. New vacuum hoses, new boost solenoids.

I’ve pressure and smoke tested the intake, charge pipes and exhaust. I can’t find an appreciable leak anywhere. Not to me too where I give it full throttle it’ll build boost, just slowly.

To top it off, it will randomly have a moment of WGDC working as it should and I’ll get an unexpected boost spike.

I’m not new to cars but, I am new to having to work on this platform so I don’t know the ins and outs of it yet.

Just trying to make it right again so I can look forward to driving it instead of dreading it.

[ShocknAwe]

How high does your boost get. Max I saw scanning your logs quickly is ~1.5 psi.

How do your outlets look? Specifically at the individual turbo snouts. Other thoughts are small boost leaks at MAP sensor TB CP baskets/rings or cracked intercooler connections or a broken tube in the core itself. Other possibility is your IM itself is physically cracked. Should get a 30FF but don't always.

Have you done a software update to see if it's DME side? Do your brakes feel good?



Side note: DME sets target boost based on load requirements which are the actual targets and set in the "tune". The boost is then based on atmospheric conditions such as IAT pressure etc and WGDC. Load loosely correlates to psi, but it's more of a %cylinder fill pressure so pressure will be adjusted somewhat. WGDC is actually something like 10 tables all part of a larger function to control base rate and smoothing adjustments to open or close the waste gates and achieve the "target boost"

[iDontRemember]

Originally Posted by ShocknAwe

How high does your boost get. Max I saw scanning your logs quickly is ~1.5 psi.

How do your outlets look? Specifically at the individual turbo snouts. Other thoughts are small boost leaks at MAP sensor TB CP baskets/rings or cracked intercooler connections or a broken tube in the core itself. Other possibility is your IM itself is physically cracked. Should get a 30FF but don't always.

Have you done a software update to see if it's DME side? Do your brakes feel good?



Side note: DME sets target boost based on load requirements which are the actual targets and set in the "tune". The boost is then based on atmospheric conditions such as IAT pressure etc and WGDC. Load loosely correlates to psi, but it's more of a %cylinder fill pressure so pressure will be adjusted somewhat. WGDC is actually something like 10 tables all part of a larger function to control base rate and smoothing adjustments to open or close the waste gates and achieve the "target boost"

Boost will go to 10+ but it’s definitely not acting normal, It won’t hold either.

Upon a cursory inspection, everything looks good. I’m going to fill with smoke and pressurize everything again this weekend and see what I can find.

Software is whatever it came with stock and has been problem free for 12 years. I don’t know how that would change but I’ll check and see if there’s an updated flash for it.

Thanks for the info on what the DME is using to compile its target.

I did notice on the way home that the pre throttle body PSI is different from the post throttle body / intake manifold. I’m going to swap a spare pre TB sensor on and see if I get a different reading.

Thanks again, I’ll report back if I learn anything or get a fix or have more desperate questions.

[ShocknAwe]

Originally Posted by iDontRemember

Boost will go to 10+ but it’s definitely not acting normal, It won’t hold either.

Upon a cursory inspection, everything looks good. I’m going to fill with smoke and pressurize everything again this weekend and see what I can find.

Software is whatever it came with stock and has been problem free for 12 years. I don’t know how that would change but I’ll check and see if there’s an updated flash for it.

Thanks for the info on what the DME is using to compile its target.

I did notice on the way home that the pre throttle body PSI is different from the post throttle body / intake manifold. I’m going to swap a spare pre TB sensor on and see if I get a different reading.

Thanks again, I’ll report back if I learn anything or get a fix or have more desperate questions.

Been a while but Im fairly sure the car is overboosting as well then if you're shooting over 10 psi.

Edit: you have a 1M which has a bit of overboost baked in stock nevermind.

Still very interesting that you have 30% wgdc once making 11psi on a spike and 50% at <3.

If you have access to it, MHD has a very nice logging suite. Don't need to use their flashing module at all.