[RSL]

Originally Posted by 335e92tx

Basically any DME adjustments to lambda (AFR) stop. See how short term trims go to zero for both banks?? that wasnt' happening before it shifted into 4th. So something thru it a curve.

Yes, the torque limits of the OTS maps are like 510mn.. its tripping those and probably going over some preset upper limit. But what the DME does after that only bosch knows.

Yes,, or like you said try the wedge route. You will be a good gunnie-pig..

No trims, yes, but there are AFR tables outside of closed loop that it follows. Can log fuel mode to determine what mode it's dropping to. If it's cat protection mode (fuel mode 6), there's a defined table that is simply RPM x load, which should be set somewhere close to the WOT AFRs used in the main table.

Torque output request is a targeting monitor used for calculations and is currently fixed at 510nm max in the DME per Jake Y. It's not even one to bother wasting a logging channel on, it will always be 510nm, assuming torque monitors a/b are set to 1.00 (which most/all tunes do).

Max torque output cap is 1000nm / 737.6ft-lbs stock (at least on DCT), but that can be changed too. It doesn't mean you won't get torque limiters long short of that without adjusting other limiters, and there are a lot. Torque limit cap is like boost ceiling, it's the topmost limiter, but you won't get remotely close to it without making some large changes in the torque tables.

Traction control is triggered off accelerometers, steering angle sensor and wheel speed sensors. AFAIK, nothing is triggered off of torque output, but emergency states certainly will reduce torque request/output, load, boost, etc.

Originally Posted by tan_rich

Hmm true, it is still an estimate. Pretty surprising that's the limit they set it as, even though people have tuned to such high numbers on stock clutches.

Torque output (nm) curve may be set close actual output from the factory on the stock tune, but it's what the DME is told output is. There's no calculation or guess of actual torque output from the motor, it's based on table values that anyone can change up or down on an unlocked map.

[335e92tx]

Originally Posted by RSL

No trims, yes, but there are AFR tables outside of closed loop that it follows. Can log fuel mode to determine what mode it's dropping to. If it's cat protection mode (fuel mode 6), there's a defined table that is simply RPM x load, which should be set somewhere close to the WOT AFRs used in the main table.

Torque output request is a targeting monitor used for calculations and is currently fixed at 510nm max in the DME per Jake Y. It's not even one to bother wasting a logging channel on, it will always be 510nm, assuming torque monitors a/b are set to 1.00 (which most/all tunes do).

Max torque output cap is 1000nm / 737.6ft-lbs stock (at least on DCT), but that can be changed too. It doesn't mean you won't get torque limiters long short of that without adjusting other limiters, and there are a lot. Torque limit cap is like boost ceiling, it's the topmost limiter, but you won't get remotely close to it without making some large changes in the torque tables.

Traction control is triggered off accelerometers, steering angle sensor and wheel speed sensors. AFAIK, nothing is triggered off of torque output, but emergency states certainly will reduce torque request/output, load, boost, etc.

Torque output (nm) curve may be set close actual output from the factory on the stock tune, but it's what the DME is told output is. There's no calculation or guess of actual torque output from the motor, it's based on table values that anyone can change up or down on an unlocked map.

thanks for covering my butt on that..

wasnt aware of Fuel mode 6 also

[Spyro235]

Hi guys, I'm new to MHD, but not new to my n54 giving me issues! I've finally got an MHD to try to help diagnose my issues.

I'm trying to diagnose two things- My surging under light throttle, and why my stage one tune is only hitting 6 psi boost, rather than the targeted 11-12. I know my turbos are failing, but they do seem to build boost for a few seconds pretty well before the waste gates rattle and throw a 30FF. I've got two logs, and I'm happy to log anything else that would help- Here they are: Surging-https://datazap.me/u/awp235/surging?log=0&data=3-12
In this, you can notice that my pedal position essentially doesn't change, while the rpm varies, the car revs up and stumbles down, my AFR's go up and down... I have no clue what to think anymore. I've replaces the injectors, the plugs are fresh, there are no codes relating to misfires, and yet sometimes it stalls when I push in the clutch. I have yet to see if it'll behave this poorly with the stage one tune installed.

Boosting-https://datazap.me/u/awp235/stage-on...og=0&data=3-14
You can see here the boost targets on my little pulls are higher than 6, and yet it levels out and maxed out right at 6. any ideas? Aren't stock DV's good for more than 6 psi?

I'm planning on having a turbo replacement done as soon as I can diagnose and solve the surging issue, as I want it to be fixed before I replace them. I would hate to have good turbos, and a car that still surges. It surges on the highway at around 80 mph, I can try to log that on my way to work tomorrow.

[335e92tx]

Originally Posted by Spyro235

Hi guys, I'm new to MHD, but not new to my n54 giving me issues! I've finally got an MHD to try to help diagnose my issues.

I'm trying to diagnose two things- My surging under light throttle, and why my stage one tune is only hitting 6 psi boost, rather than the targeted 11-12. I know my turbos are failing, but they do seem to build boost for a few seconds pretty well before the waste gates rattle and throw a 30FF. I've got two logs, and I'm happy to log anything else that would help- Here they are: Surging-https://datazap.me/u/awp235/surging?log=0&data=3-12
In this, you can notice that my pedal position essentially doesn't change, while the rpm varies, the car revs up and stumbles down, my AFR's go up and down... I have no clue what to think anymore. I've replaces the injectors, the plugs are fresh, there are no codes relating to misfires, and yet sometimes it stalls when I push in the clutch. I have yet to see if it'll behave this poorly with the stage one tune installed.

Boosting-https://datazap.me/u/awp235/stage-on...og=0&data=3-14
You can see here the boost targets on my little pulls are higher than 6, and yet it levels out and maxed out right at 6. any ideas? Aren't stock DV's good for more than 6 psi?

I'm planning on having a turbo replacement done as soon as I can diagnose and solve the surging issue, as I want it to be fixed before I replace them. I would hate to have good turbos, and a car that still surges. It surges on the highway at around 80 mph, I can try to log that on my way to work tomorrow.

Well, we will prob have to look at one at a time bc they really need different things logged. Anyway, for your WFO runs, you really dont have it floored for more than about 2.5 secs. Gonna need a little more than that - WGs never drop down out of spool really. So I dont find it surprising you dont see more than 6psi.

. And you need to turn off the logging for vanos and WGDC% base value and turn on short term fuel trims.. .

Now for surge...

Kind of a similar deal. Its hard to tell when you get to the cruise speed. You should turn on gear and also speed. It seems by about timestamp 93.x, you are at a cruise speed and accelerator position is stable. There is a little change in throttle percent but not much. The intake vanos seems consistent so I dont think that is a factor. There is a pretty good variation in Lambda in that time, it moves from 15 to 17+ at times. You done O2 sensors on this thing? ? I start with resetting lambda regulation and then maybe lambda sens. But I think it will need front o2s (having STFT included in logs would help) before long... number of miles?

[RSL]

It should be above 6psi just about anywhere on stock turbos regardless of where spool mode ends and WGDC stays pegged constantly at WOT. Seems really likely there's a boost leak, bad solenoid(s) or vacuum line/canister. WGDC is increased below 9% pedal and reduces with more pedal until it increases again with WOT, is there a rattle option set or something?

It doesn't look like the surging and boost problem are on the same map, stick to one for testing with no flash options that aren't absolutely necessary (rattle fix, etc.), but I'd start with the boost problem first. Give the vacuum lines/canisters a once-over and maybe test the solenoids. If still no luck, pressure test the intake tract.

Surging doesn't seem uncommon on the current OTS maps, maybe next version will tone it down, but little you can do about it on a locked map either way, so work on what you have control over (missing boost).

[Spyro235]

For what it's worth, the surging is a stock issue that didn't change at all with a tune. The surging map is actually at 0 speed- that's just sitting with 2% pedal in neutral. I can get a moving surging log on my way to work in a bit. It happens strictly at like 2950rpm, from 80 mph to 85. I will add stft. The only option checked is the burble option.
Car has 141k on original turbos, wastegates rattle like crazy but the car only throws limp mode after 4-5 seconds of WOT. I mainly tuned the car last night to see if anything with the surging changed.

Thank you guys for all your help!

[335e92tx]

Originally Posted by Spyro235

For what it's worth, the surging is a stock issue that didn't change at all with a tune. The surging map is actually at 0 speed- that's just sitting with 2% pedal in neutral. I can get a moving surging log on my way to work in a bit. It happens strictly at like 2950rpm, from 80 mph to 85. I will add stft.
Car has 141k on original turbos, wastegates rattle like crazy but the car only throws limp mode after 4-5 seconds of WOT. I mainly tuned the car last night to see if anything with the surging changed.

Thank you guys for all your help!

that may be true but there can be several causes. Normally at low rpm its more likely to be vanos related. The rpm you have its harder to say.

Again, might the case but its hard to tell without a load. DME is gonna do all kinds of stuff based on load..

[Spyro235]

Originally Posted by 335e92tx

Again, might the case but its hard to tell without a load. DME is gonna do all kinds of stuff based on load..

Here's a surging log at about 75mph, steady state cruise. It didnt keep my selections of fuel trim, speed, and gear, so I'll log it again with those on my lunch.
https://datazap.me/u/awp235/surging-...og=0&data=3-15
Looking at this, my intake side vanos is oscillating when the car starts surging at about t= 105. Could that be a cause? The load is oscillating around 34ish, so it does have some load. O2's are possible and I'll get logs with fuel trim asap.

Here's a quick pull through 2nd and 3rd, until i heard the half engine light get thrown.
https://datazap.me/u/awp235/boost-th...og=0&data=3-15

and here's one that was just a 5th or 6th gear pull for a bit, to keep it in boost for more than a second or two. Definitely doesn't breach 6-6.1ish, and I fell it certainly had time in the 14 seconds of WOT to boost up to it. I guess I need to get my hands on a vacuum tester...
https://datazap.me/u/awp235/pull-lon...og=0&data=3-15

[RSL]

Surging can definitely happen on any map (including stock, but rules out tune issues) and you clearly have other issues that are contributing. If you're 141k miles on original vacuum hoses, canisters, BCS, etc., pretty good chance it's one or more. There are some common places hoses break with age, like under the engine cover, and you don't really need a vacuum tester for those or canisters, just a close visual inspection. At that mileage, I'd give the valve cover a look while the cover is off and look for any cracks/oil residue too.

More logs isn't going to resolve anything, you need to get under the hood and take a look. When surging happens, just about everything moves up and down cyclically, so fix boost first and then see if the surging even remains on the stock the bin.

[335e92tx]

RSL has seen more than I but I would think there has to be some good amount of air being admitted somewhere. I would not think it would be staying that lean otherwise - it goes to 19 to 1 at times. So it only does it at 3000 or so rpm?? not 2000-2400?? If thats the case Id say there is a large plastic part that has a crack that is vibrating as rpm goes up and it is letting in air. The only thing I could think of that would do that would be in the PCV area - but I guess that would not be metered air.. so VC is prob all thats left.

[Spyro235]

I'll definitely start looking for cracks and worn hoses when I get a chance. The trim levels bounce all around with the surging, I just logged it. When My mechanic was originally looking for vacuum leaks he said he checked the whole engine bay, and the only thing he found was actually a pretty badly cracked VC on the rear passenger corner of it. It was replaced with a new OEM VC. I'll start going through the hoses and take the cowling off to look at the stuff under it. If I have a real boost leak, which I really must, I suppose the stock charge pipe could definitely have failed by now, in addition to all the rest of the parts you've mentioned. Matt at ZNM is my mechanic, and he told me he extensively smoke checked the bay, and didn't find anything else leaking. I trust him, but at the same time it can't hurt for me to go in and look at it myself.

[Spyro235]

Originally Posted by 335e92tx

RSL has seen more than I but I would think there has to be some good amount of air being admitted somewhere. I would not think it would be staying that lean otherwise - it goes to 19 to 1 at times. So it only does it at 3000 or so rpm?? not 2000-2400?? .

It will occasionally lurch at any rpm, like a hiccup, but it will only consistently lurch JUST off idle at 700-1000ish rpm. and right at 3k-3300 rpm. up until a few long drives recently, it would start at 2900 and go until 3150ish, but your crack theory could definitely hold some credibility. If the crack continued spreading, the resonance where it's affected would change. Of course, this is all hearsay until I just look at all the pieces. I find the n54 very intimidating, mainly because it's much more complicated than the m54 I'm used to doing heavy work on. I replaced the clutch on my 330, but I'm pretty nervous about breaking something expensive while trying to work on the n54.

[Spyro235]

Originally Posted by RSL

It should be above 6psi just about anywhere on stock turbos regardless of where spool mode ends and WGDC stays pegged constantly at WOT. Seems really likely there's a boost leak, bad solenoid(s) or vacuum line/canister. WGDC is increased below 9% pedal and reduces with more pedal until it increases again with WOT, is there a rattle option set or something?

It doesn't look like the surging and boost problem are on the same map, stick to one for testing with no flash options that aren't absolutely necessary (rattle fix, etc.), but I'd start with the boost problem first. Give the vacuum lines/canisters a once-over and maybe test the solenoids. If still no luck, pressure test the intake tract.

Surging doesn't seem uncommon on the current OTS maps, maybe next version will tone it down, but little you can do about it on a locked map either way, so work on what you have control over (missing boost).

RSL, I did notice while looking at parameters over lunch that my wastegates seemed to shoot closed, and then drop down while "trying" to build boost at WOT to around 30%. This does strike me at pretty weird, as I would think if it's not hitting target, it would try to close the wastegates to build more boost up. I'll have to examine everything and see if I can borrow a vacuum tester from someone to test the solenoids. One of my drift buddies should have one laying around.

[RSL]

Originally Posted by 335e92tx

RSL has seen more than I but I would think there has to be some good amount of air being admitted somewhere. I would not think it would be staying that lean otherwise - it goes to 19 to 1 at times. So it only does it at 3000 or so rpm?? not 2000-2400?? If thats the case Id say there is a large plastic part that has a crack that is vibrating as rpm goes up and it is letting in air. The only thing I could think of that would do that would be in the PCV area - but I guess that would not be metered air.. so VC is prob all thats left.

Can definitely be multiple concurrent issues, I usually start with the easiest things first

Originally Posted by Spyro235

RSL, I did notice while looking at parameters over lunch that my wastegates seemed to shoot closed, and then drop down while "trying" to build boost at WOT to around 30%. This does strike me at pretty weird, as I would think if it's not hitting target, it would try to close the wastegates to build more boost up. I'll have to examine everything and see if I can borrow a vacuum tester from someone to test the solenoids. One of my drift buddies should have one laying around.

Seems like odd DC movement, which is why I thought maybe a rattle setting. If vacuum and leaks have been tested for and definitely eliminated already, continue with a pressure test (if not done already too) and solenoids. If you have known good solenoids to swap in, that would be a quick one to get out of the way.

[Ballistic]

Hey Guys,

I adjusted both the wastegate arms yesterday and just took a log. Less rattle and better boost building/maintaining now.

MHD Stage2+ 91oct with DP's and Ebay IC.
https://datazap.me/u/ballistic/bmw-n...=0&data=3-5-22
A second log with more gears is also in there.

Fuel not being able to deliver Our Dutch 91oct EUR95 fuel is not good enough for MHD Stage2+ 91oct
And IC cannot keep IAT's down. Need to upgrade to a better one.

Any other remarks? Car feels strong.

[335e92tx]

Originally Posted by Ballistic

Hey Guys,

I adjusted both the wastegate arms yesterday and just took a log. Less rattle and better boost building/maintaining now.

MHD Stage2+ 91oct with DP's and Ebay IC.
https://datazap.me/u/ballistic/bmw-n...=0&data=3-5-22
A second log with more gears is also in there.

Fuel not being able to deliver Our Dutch 91oct EUR95 fuel is not good enough for MHD Stage2+ 91oct
And IC cannot keep IAT's down. Need to upgrade to a better one.

Any other remarks? Car feels strong.

yeah, a 14c increase is pretty high. Most everything I see looks ok.
AFRs are about right, Trims are ok. A little timing getting pulled but it zeros out a bit after the shift. The biggest issues I see are sometype of throttle closer at the shift (is this a DCT or ZF?) and also going over boost/load targets a bit. So you wont make much more power on that map I dont think even with cooler IATs. You are driving the snails pretty good.

[Aus335iguy]

This isnt directed at anyone in particular so please dont feel guilty - I think as a courtesy if you post a log here and someone like 335e92tx or @RSL or whoever it may be respond with advice the least we can do is say thanks and hit the appreciate button at the bottom of the post. That gives them recognition for their contribution. It?s not a lot to ask given that in some cases they are helping to diagnose what can be very expensive problems..

Here?s to the people who help !

[RSL]

I mostly just chime in, but guilty of not passing them around enough myself

[Ballistic]

Originally Posted by 335e92tx

yeah, a 14c increase is pretty high. Most everything I see looks ok.
AFRs are about right, Trims are ok. A little timing getting pulled but it zeros out a bit after the shift. The biggest issues I see are sometype of throttle closer at the shift (is this a DCT or ZF?) and also going over boost/load targets a bit. So you wont make much more power on that map I dont think even with cooler IATs. You are driving the snails pretty good.

Thanks for your input! Now that I mentioned it, I forgot to disable DSC but I don't think that is the source of the shifttime overboost problem.
I am still running the stock diverter valves. Do you think it might be possible that they are too slow to release pressure?

[335e92tx]

Originally Posted by Aus335iguy

That gives them recognition for their contribution. It?s not a lot to ask given that in some cases they are helping to diagnose what can be very expensive problems..

Here?s to the people who help !

thanks - but im not sure how good my analysis is at times.. the big guns will follow along.. ;-)

Originally Posted by RSL

I mostly just chime in, but guilty of not passing them around enough myself

x2

[335e92tx]

Originally Posted by Ballistic

Thanks for your input! Now that I mentioned it, I forgot to disable DSC but I don't think that is the source of the shifttime overboost problem.
I am still running the stock diverter valves. Do you think it might be possible that they are too slow to release pressure?

eh, not likely. So this is a DCT trans..?
I see no accelerator pedal lift so I can only conclude so.

IF yes, the issue is more likely some DME limit in the OTS map for the DCT. Some of the V8 maps they are about to release from wedge for MHD might help or a custom tune might be needed. That would raise some load targets more as you seem to need.

[Ballistic]

Sorry, forgot to tell this is running the ZF 6AT with xHP Stage3 flash.

I need to read up some more on load targets to fully understand them.