Make and share datalogs!

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Make and share datalogs!

Postby bigBADbenny » Mon Oct 11, 2021 11:47 am

Make a log with tuning parameters.

Read this guide made by Eric, Torqued Performance tuning, he’s a renowned eTuner based in the USA.
https://www.wrxforums.com/threads/erics ... logs.7623/

For AccessPort users: https://cobbtuning.atlassian.net/wiki/s ... To+Datalog And: https://www.youtube.com/watch?v=uIo6tqFtA3w

If you’re interested in how to graph and analyse datalogs, here’s a full breakdown of the process for an my07 GT that is returning “take action” results in Learning View: http://forum.liberty-asn.au/viewtopic.php?f=18&t=37404

Whilst I’m not a tuner, I consult regularly on state of tune and DTC issues, worldwide, I have an extensive archive of known good and bad logs, and extensive contacts in the enthusiast community. I’m happy to help out with your logs but only by forum or group posts, please don’t PM.

Note: if you have any obdii plug &/or app combo, but *no logging* and need a quick diagnostic check, make a note of these on board diagnostic parameter values :
During warm idle:
RPM
AFR
Intake manifold vacuum
Fuel correction
Fuel learning
Engine coolant temperature
Is idle stable, year, model, engine, transmission?

Eg for an h4 turbo, the warm idle stats are roughly:
RPM: 700-800
AFR: 14.7
Intake manifold vacuum: -10psi/-20in/hg
Fuel correction: ideally zero or within +/-5%
Fuel learning: within +/-5%
Engine coolant temperature: 86-94C
Is idle stable: eg within 700-800rpm.

If not, get back with your figures as they’re a huge clue to your current state of tune, in closed loop.

Ideally you already have a Cobb AccessPort or OS open source SSM obdii logging interface, eg Vag-com, OBDlink LX or MX or Tactrix Openport, if not:
For open source, this is as affordable as buying a $15 clear blue case VAG-COM KKL 409.1 usb obdii plug.
This works with a PC with FreeSSM (live data no logging), RomRaider Logger and Learning View; and on Android with BtSSM with the appropriate OTG female usbA to your phone usb adapter.

Logging off boost is fine, unless you’re diagnosing load or boost related issues, on condition that you’ve already properly confirmed no boost or lcv leaks eg using this guide:
viewtopic.php?f=6&t=36513


20 minutes cold start to warm log, a/c off

See below for recommended parameters.
Its possible to get a good idea of basic engine health from a cold to warm idle, no haptic input, no a/c.
Since it’s a repeatable test it’s a good baseline to track any improvement after repairs.
If the engine has had recent significant maintenance or repair, reset the ecu prior to logging warm to hot, no haptic input, plus a following off boost fuel learning run.


20 minutes plus, street and freeway driving,

long part-throttle & vacuum pulls… and at least a few minutes of WARM idle :)

For more detail on the intent behind making diagnostic datalogs see this reply: viewtopic.php?f=6&t=36932&p=459553#p459553

Being stabby with the throttle will fill the datalog with transient data, so limit abrupt throttle to less than half of the log.
Warm idle and steady freeway cruise are useful for analysing closed loop operation, so include a few minutes or way more.
If there’s a drivability fault or issue, try to capture that in the datalogs.


Only if safe for your engine of course, if it can only idle, log idle, again if safe to do so.

The more data the better, by this I mean the length in time of the log.

After ecu reset, some advise to “learn the ecu in” with an off boost drive with some traffic & freeway cruise.
An ecu reset and idle relearn (DBW throttle) might be necessary after maintenance, eg the process can cure rev hang after UEC treatment.

Idle relearn: turn off all accessories, open drivers window, reset ecu (scan tool or pull battery negative temporarily and press brake to drain the electrical system including ecu fuel and knock learning), start the engine via drivers window, let the engine idle for 15minutes plus until fully warmed up.

Ideally you’ll datalog this process and the subsequent ecu relearn drive.

Sharing logs!

*share* a *link* to the csv file using google drive, wetransfer, dropbox etc.

The idea with sharing logs is to upload the csv file from your pc, laptop etc, to the cloud, then share a link to the file in the cloud, aka online data storage.

Its also possible to use the Datazap app, again upload the log csv to the app, share from the app.

Or from the Wetransfer website: send the csv file to your own email, share the download link from the upload confirmation email.

Learning parameters are generally FBCK, FLKC, Fuel Correction (STFT/short term fuel trims) and Fuel Learning (LTFT/long term fuel trim), Knock Sum.

Other essentials parameters for logging are referred to as tuning parameters, but generally vehicle speed, petrol afr, rpm, tps, manifold relative pressure and engine coolant are essential for log clarity.

How to log AP:
https://www.google.com.au/search?q=how+ ... ent=safari

Cobb AP parameter list:

https://cobbtuning.atlassian.net/wiki/s ... nitor+List

When logging, use tuning parameters:
Less parameters = better log resolution, eg don’t use every available parameter, use the parameters in these lists as a starting point and add or remove parameters as required, eg per cylinder misfires/roughness and avcs for a misfire fault, fuel pump duty cycle for a fuelling issue (if stock FPCM), rear O2 parameters for unexpected fuel trims on cars w/o rear O2 delete, etc.


Logging Parameters for H4DOTC:
From Torqued Performance:
A/F Correction #1(%)
A/F Learning #1(%)
A/F Sensor #1(AFR)
Coolant Temperature (C)
Engine Load (g/rev)
Engine Speed
Feedback Knock Correction
Fine Learning Knock Correction
IAM/DAM
Ignition Total Timing
Injector Duty Cycle
Intake Air Temperature
Knock Sum
Manifold Absolute Pressure (PSI)
Manifold Relative Pressure(corrected)(PSI)
Mass Airflow (g/s)
Mass Airflow Sensor Voltage
Throttle Opening Angle(%)
Vehicle Speed (mph)
Optional (but mandatory for health check):
VVT angles (L&R)
WDC

VVT specific parameters:
Engine Speed
Vehicle Speed (mph) (kph if not logging for a USA based tuner)
VVT angles (L&R)
OCV duty (L&R)
OCV current (L&R)

Logging parameters for H6DO:
From XRT

32bit ECU - H6 3.0R

A/F Correction #1 (%)
A/F Correction #2 (%)
A/F Learning #1 (%)
A/F Learning #2 (%)
A/F Sensor #1 (AFR)
A/F Sensor #2 (AFR)
VVL Lift Mode (raw ecu value) ((aka ALVS))
Accelerator Pedal Angle (%)
Coolant Temperature (C)
Engine Load (Calculated) (g/rev)
Engine Speed (rpm)
Fine Learning Knock Correction (degrees)
IAM (multiplier)
Ignition Total Timing (degrees)
Injector Duty Cycle (%)
Intake Air Temperature (C)
Intake VVT Advance Angle Left (degrees)
Intake VVT Advance Angle Right (degrees)
Learned Ignition Timing (degrees)
Manifold Absolute Pressure (psi)
Mass Airflow (g/s)
Mass Airflow Sensor Voltage (V)
Oil Temperature (C)
Throttle Opening Angle (%)
Vehicle Speed (km/h)

Parameters for Cobb AP (see next posts) Btssm will have similar but different names, if in doubt just google it ;)
Stay safe and no hero mode!

Here’s an in depth video explaining some of the concepts related to data logging, specifically the role of fuel trims.

https://m.youtube.com/watch?v=FP3bu3UBz5k

And misfire diagnostics:

https://m.youtube.com/watch?v=4iYBzP3kUjk



;)
Last edited by bigBADbenny on Wed Oct 25, 2023 10:11 am, edited 30 times in total.
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Re: Make a log!

Postby bigBADbenny » Tue Apr 19, 2022 10:12 am

Here's the H4 parameter list with Cobb names:

AF Correction 1 (AF Correction 1)
AF Learning 1 (AF Learning 1)
AF Sensor 1 Ratio (AF Sens 1 Ratio)
Calculated Load (g/rev)
Coolant Temperature (C)
Engine Speed (RPM)
Feedback Knock Correction (Feedback Knock)
Fine Knock Learning (Fine Knock Learn)
Dynamic Advance Multiplier (Dyn Adv Mult)
Ignition Timing (Ignition Timing)
Inj Duty Cycle (Inj Duty Cycle)
Intake Temperature Pre Turbo (Intake Temp)
Knock Sum (Knock Sum) (per cylinder on some models)
Manifold Abs Pressure (Man Abs Press)
Manifold Rel Pressure (Boost)
Mass Airflow (MAF)
Mass Airflow Voltage (MAF Volts)
Throttle Position (Throttle Pos)
Vehicle Speed (Vehicle Speed)
AVCS Intake Left (AVCS In Left)
AVCS Intake Right (AVCS In Right)
AVCS Exhaust Left (AVCS Exh Left)
AVCS Exhaust Right (AVCS Exh Right)
Wastegate Duty (Wastegate Duty)


If you suspect misfires also log Cylinder 1,2,3,4 etc Misfires aka Roughness.
If you suspect fuel system issues eg maxed out fuel corrections with
stock fuel pump control module, log:
Fuel Pump Duty Cycle.
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Logging cold to warm starts, ecu resets, datalogging intent…

Postby bigBADbenny » Mon Oct 09, 2023 8:37 am

Logging cold to warm starts, ecu resets, datalogging intent, anxiety vs tranquility port.

Logging is all about gathering data, the data also needs intent and context.
So cold to warm idle with no haptic or control input shows how the ecu works in closed loop operation as the coolant temperature rises and stabilises.
After an ecu reset this process includes ecu learning of fuel trims, IAM/DAM, knock and idle relearning (the latter for DBW engines).

What’s important is that the two cold to warm logs are fundamentally repeatable tests, the former representing the “learned in” state of tune, the latter being the transition from unlearned to learned and in the case of some systems, eg AVCS, the transition from uncalibrated to calibrated.

Either way, we’re looking for the emissions and other systems to stabilise as the engine becomes fully warm.

AVCS does not become active until coolant temperature is 60 or 80’c, and requires throttle and or load input to to advance VVT angles, meaning to specifically recalibrate AVCS, especially on later models, it may be necessary to follow FSM AVCS related DTC or TSB diagnostic procedures that relate specifically to the drive cycles & procedures required for full AVCS recalibration.

The two tests are useful especially where an emissions related issue is being diagnosed, and can be used as baselines befor and after major work or maintenance.

What we do want to take note of is the time of operation since the last ecu reset and if DTC’s are thrown, are the codes set at key-on, persistent, or are they triggered later, eg due to learned conditions after a number of drive cycles and do the codes resolve themselves, again, after a number of drive cycles.

This aspect is important because we want to be able to drive without resetting the ecu at all, so as to not have to endure limp mode and the related driving limitations, and obviously to not damage the engine further due to the fault it’s suffering from.

So generally if you are doing diagnostic logging, there’s an issue with the vehicle, so in addition to the two types of cold to warm idle logs, if it’s safe to drive the car, make an off boost driving log with gentle throttle input and a mix of stop start, steady cruise and load conditions and finishing with a few minutes of warm idle.

Ideally the logged drive will be local and repeatable, as with the idle logs, any log can be overlaid for comparison in data visualisation software eg MLVHD, it’s a surprisingly useful feature.

Think of suburban streets, a long hill and a section of freeway. For these logs harsh throttle inputs are transient data, whilst they will be filtered out, it’s better to have consistent steady control inputs during the logging.

Save making pulls for healthy cars which are being tuned or tested. A car that works well in closed loop will generally work in open loop, not so much the other way around.

Hit me up if anything is unclear, cold to warm logs are useful checkpoints in the diagnostic process, they don’t really need to be repeated until the state of tune/drivability has changed for better or worse.

If the car has a state of tune or drivability issue and still is safe to drive, I recommend logging every drive until the issue is resolved, a process informed usually via log analysis and or system health checks and tests.

The logging data rate is very low on a stock ecu, usually around 10 recording events per second, so we’re looking to build a picture of the average data over time through volume eg length of time in logging, meaning 20 minutes plus is ideal and usually results in logs of around 2MB, perfect for sharing via email or eg Datazap site.

So the suggested parameter lists are really important to build a picture of how the operator is operating the car and how the car is responding.

If you can settle on one set of parameters as general use (as suggested) that’s great because multiple logs can be opened concurrently or overlaid: if the parameters are the same.

For some diagnostics you might want to focus on a particular aspect of the available parameters, enabling and disabling parameters as required.
Examples being misfires, in-depth AVCS issues beyond sync issues. Either way be sure to name and save your various parameter sets in the logging app so you can return to the fundamental set once your issues are resolved.

Obdii gauges and or displays are a distraction, don’t get sucked into watching the figures at your peril during driving.
The antidote to gauge fixation is to either hide the logging device from view, or set it up essentially as a more useful extension of your dash clocks.

In my car, the BtSSM gauges are displayed on the old school stock Nav screen. So I’m looking at boost vacuum, corrected road speed, VVT angles (defacto oil pressure for ej255 etc), volts, coolant, rpm, afr, inlet temp and the sole diagnostic indicator is a small IAM digital gauge, since if DAM drops, I’m on a need to know basis.
Rpm, coolant and boost have alarms, the gauge goes red if a limit is exceeded.

So just the basics, no anxiety, the setup is way more reassuring than no gauge eg especially for coolant and vacuum/boost, corrected road speed.

Save geeking out over the figures for datalog analysis software, where all the data can be seen in context and more informed conclusions can be made.
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Posts: 10420
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