[TDIwyse]

Originally Posted by TDIwyse

...I think this is because the resolution of the speed data is too course for the resolution of the small time step... going to larger step sizes, where the resolution of the recorded speed is better, actually produces more accurate results...

I think by looking at the resolution of the speed data, we could determine what time step would work best. Going smaller sampling time step resolution than the speed measurment allows (distance/time) will actually create distortion/noise in the calculation of acceleration...

In my example above the resolution for mph measurement was 0.1 mph.

[pheno]

Yes, agreed. Is the Vehicle speed calculated from wheel speed sensors or final drive ? Which one has better resolution ? resolution for wheel speed is defined by amount of 'teeth' in bearing hub. The more the better.

Edit: I have some new data hopefully I can solve RPM and vehicle speed.

[WreckerX5d]

Originally Posted by pheno

Yes, agreed. Is the Vehicle speed calculated from wheel speed sensors or final drive ? Which one has better resolution ? resolution for wheel speed is defined by amount of 'teeth' in bearing hub. The more the better.

Edit: I have some new data hopefully I can solve RPM and vehicle speed.

I believe it's calculated by the wheel speed sensor, judging by another thread on the forums.

[pheno]

Originally Posted by Wrecker335d

I believe it's calculated by the wheel speed sensor, judging by another thread on the forums.

Ok, thanks. That makes sense since it should be the most accurate method.

[pheno]

I have now some "high resolution" data from can bus: acceleration, vehicle speed in km/h, wheel speed (pulse count per wheel) which update every 20ms. Then there's rpm and throttle position which update at every 10ms! TestO logged simultaneously so I can match timestamps but from two different files.

Also I could be able to get high res. data from transmission like input shaft and output speed. But haven't tested that yet. Got some help with this from a fellow so credits go where it belongs.

Working with excel seems not to be a good idea as its bit manipulation functions are a bit cumbersome and I'm banging my head on the wall :-) So I haven't been able to put raw data into usable format. I'll have to do conversion in the program.

[JuiceQuadre]

Is there a good cable from amazon/ebay/aliexpress you could recommend for Testo?

I dont wanna necessarily buy something cheap but i dont wanna waste money on expensive one if the cheaper cables do the same job.

[Yozh]

Originally Posted by JuiceQuadre

Is there a good cable from amazon/ebay/aliexpress you could recommend for Testo?

I dont wanna necessarily buy something cheap but i dont wanna waste money on expensive one if the cheaper cables do the same job.

http://www.e90post.com/forums/showthread.php?t=1361059

[pheno]

Originally Posted by JuiceQuadre

Is there a good cable from amazon/ebay/aliexpress you could recommend for Testo?

I dont wanna necessarily buy something cheap but i dont wanna waste money on expensive one if the cheaper cables do the same job.

I've bought two of these from ebay with transparent enclosure and white PCB for ~15EUR. Both have worked without issues. But I guess I just might have been lucky.

[JuiceQuadre]

Originally Posted by Yozh

http://www.e90post.com/forums/showthread.php?t=1361059

Wow i see its a brand new thread=) i think that might be my best option

[JuiceQuadre]

Originally Posted by pheno

I've bought two of these from ebay with transparent enclosure and white PCB for ~15EUR. Both have worked without issues. But I guess I just might have been lucky.

Yea i guess its about luck with those.. Not sure i wanna go that way

[pheno]

Been too busy lately but got a change to try new CAN Bus code in Testo. Here's only RPM and throttle but it looks to be stable. Next I'll add wheel speeds.
Data rate here is 100Hz. The video doesn't do justice to refresh speed I can see on the screen . It really is 100 per second and very smooth..

[JuiceQuadre]

Is there a way to diagnose/logg bad MAF?

I cleaned mine, getting some improvement in cars behaviour but maybe not as big as id hope for, while doing that i found out the MAF is still original 2006 one, which means it can have 180k miles on it.

Dont wanna buy parts just for the sake of it, but i feel the car should/could do better in terms of responsivity and power.

[victorhall]

Hello all,
I've been spending the last week reading through all the excellent posts by pheno, Yozh, TDIWyse, DWR, and everyone else. You guys are amazing (especially you pheno - great work with Test-O - it's a great resource.)

I'm troubleshooting my X5d, which goes into limp (throws a 429A code (DDE: Boost-pressure control, low-pressure stage, control deviation). My best guess so far is a "big" turbo which isn't doing it's job.
From my graph, you can see boost pressure dropping at about 3,000 rpm, at the same time as the compressor bypass and turbine control valves give the signals to go full "big turbo." I've used Rheingold to test the vacuum system, and all appears to be working normally. I can actuate the compressor bypass, turbine control, and wastegate valves all manually through Rheingold's test procedures.

Figured I'd post my plot so far as a data point, and am happy to share more info, raw data, etc...to help develop tools etc if it will help. Learning curve is still steep for me - just let me know how I can help.

Thanks again for all your amazing info guys, and, of course, feel free to offer any thoughts on what might be causing my issue.


SOLVED: The 429A code was caused by exhaust blockage. The stock SCR was still in place, and after running with DPF deleted, exhaust gummed up, and would not allow the LP (big) turbo to spool up. Solution was to remove the SCR. Posted new graph (with other potential issues) on page 5.

[TDIwyse]

You might want to add the EMP sensor to your logs to help diagnose: STAT_Exh_pTrbnUs_full_WERT

It kind of looks like either the compressor or turbine bypass valve is not actually switching during your testing. Looking at what the EMP's do should help see what turbine side is doing. You should see a dramatic change in EMP behavior during the switch-over.

Or maybe pull the intake boot off the LP compressor and check the compressor wheel for damage?

Good luck.

[victorhall]

TDIwyse,
Thanks for the tip on STAT_Exh_pTrbnUs_full_WERT. That would have taken me all week to find by trial and error.
Did another run, and here are the results. Looks like a momentary dip in exhaust pressure, then it's back up...my best guess is big turbo not charging air properly - will have to investigate.
The tail of the run is when limp mode kicks in, and my guess is a release via the wastegate of pressure. Too bad there's no obvious way to see if the wastegate is getting a signal. I would have thought that would be an obvious parameter for BMW to have in here...maybe it's buried.

-Vic

[TDIwyse]

Originally Posted by victorhall

TDIwyse,
Thanks for the tip on STAT_Exh_pTrbnUs_full_WERT. That would have taken me all week to find by trial and error.
Did another run, and here are the results. Looks like a momentary dip in exhaust pressure, then it's back up...my best guess is big turbo not charging air properly - will have to investigate.
The tail of the run is when limp mode kicks in, and my guess is a release via the wastegate of pressure. Too bad there's no obvious way to see if the wastegate is getting a signal. I would have thought that would be an obvious parameter for BMW to have in here...maybe it's buried.

-Vic

Am I reading your plot correctly? Does it say STAT_Exh_pTrbnUs_full_WERT reaches a max value of only 3000 mbar? Your values are very different from what I've seen on my vehicle.

The dip is what I normally see when the turbines transition.

Not sure of your modification status, but on stock turbo's and a much earlier and less aggressive tune, here's an example of boost/emp behavior from my vehicle. STAT_Exh_pTrbnUs_full_WERT does not limit at 3000 mbar like you are seeing. Not sure what to make of that ...

http://www.e90post.com/forums/showpo...&postcount=211

[Yozh]

If red is boost and yellow is EMP, then boost drops off and EMP dips and climbs at the alleged switchover point. Also a significant deviation from the requested boost. I would look at a stuck closed compressor bypass and it's control through the EL that may be dead (does not open upon a go signal). Or an unlikely scenario of a failed open pressure converter for the turbo switchover.

[JuiceQuadre]

If i understand corretly there are diagnostic tests in Rheingold to test these systems, but they dont really work?

I plan on using Rheingold when my cable arrives

[TDIwyse]

Originally Posted by TDIwyse

Am I reading your plot correctly? Does it say STAT_Exh_pTrbnUs_full_WERT reaches a max value of only 3000 mbar? Your values are very different from what I've seen on my vehicle.
....

Ah, I see the confusion... you used STAT_Exh_pTrbnUs_WERT and not STAT_Exh_pTrbnUs_full_WERT.

The parameter you logged clips at 3000mbar and doesn't give the full EMP range.

I agree with Yozh that it could be something with your compressor bypass. It looks like your turbines are switching (although using the correct EMP parameter for the full range behavior would still be good to verify) but your LP compressor does not seem to be engaging when it's turbine is getting the exhaust flow. So the HP compressor would be the one still being utlized for the intake flow to compress the air, but it has little to no exhaust energy to drive its turbine because the flow has been switched to the LP turbine.

Or it could be something completely different going on.

[victorhall]

Great stuff guys - thanks!
TDIWyse, great catch on missing the "full" in STAT_Exh_pTrbnUs_full_WERT - I'll need to re-run...you almost need to speak two additional languages. I re-graphed the info in xcel, and it does show the flattening out of a "maxed" sensor a little clearer - just validating what you guys have already said.

I do plan to get a visual on the LP compressor to see if I can see any issues with it.

Rheingold does allow testing of the vacuum system for the actuators for the:
- Turbine Control calve
- Compressor Bypass valve, and the
- Wastegate.

After the 429A code, I go to test plan (or something like that) which kicks me into a testing program for the above. While idling, Rheingold sends the signal to actuate each of those valves, so you can do a visual to make sure the actuators are moving quickly and far enough. That system checked out when I did the diagnostic, which leads me to believe that the LP turbo is causing problems.

[TDIwyse]

Originally Posted by victorhall

... I re-graphed the info in xcel, and it does show the flattening out of a "maxed" sensor a little clearer - just validating what you guys have already said.

If you put your RPM data on the left column of your selected data to plot, then choose "Scatter Plot", it will graph all the other columns of selected data vs RPM on the X axis. It makes it easier to see what things do versus rpm (similar to a dyno plot where rpm is on the x axis).

[victorhall]

Originally Posted by TDIwyse

If you put your RPM data on the left column of your selected data to plot, then choose "Scatter Plot", it will graph all the other columns of selected data vs RPM on the X axis. It makes it easier to see what things do versus rpm (similar to a dyno plot where rpm is on the x axis).

Good advice (please keep it coming!)
Here's a re-tread of that data. I'm hoping to make a re-run tonight with the right exhaust pressure parameter.

Also, in response to an earlier question - this is all stock programming. DPF and EGR have been removed.

-Vic