SCT X4 Datalogging

by Michael Decipha Ponthieux
Posted: 2021-04-05
Last Updated: 2021-04-07

SCT Device Files (.cef)

Device (.cef) Files VS Calibration (.mtf) Files
An SCT device file is a .cef file. A device file IS NOT a calibration file. A calibration file (.mtf) is what your tuner used to create the .cef device file. A .cef device file is only useable on the SCT device it was written for and cannot be sent to another tuner for review nor can it be used on a different device. Only an .mtf calibration file can be sent to another tuner for review which can then be used to create .cef device files.

If you have already wrote your tune to the vehicle you can skip down to Datalogging.

Before firing up your modified vehicle for the first time you must first write your custom tune to the handheld then to the vehicle.
This is done in 3 steps.

Step 1 - You must download the .cef device file from your custom tuner that they have written custom for your specific vehicle and have assigned to your specific device's serial number.

Step 2 - You will need to then use the SCT Device Updater tool to write the device file to the xcal or SCT device.
Here is the link to the device updater to write the device file.

WARNING: DO NOT UPDATE THE XCAL just update the device file only.

Step 3 - You will need to plug the xcal in to the vehicles obd-2 port and then write the custom tune to the vehicle.

BE AWARE that the first fire up after the first write may cause your vehicle to run funny. This is perfectly normal and nothing to be worried about.

Now you will need to get livelink intalled.
Here is the link to downloads sct livelink II to datalog.
Saving Your Datalog to send for Review
After you have completed a log click the file icon at the top left of the program and select SAVE then select DATALOG (*.csv) Be sure to remember where you save the file to. Next go to the folder where you have saved the file and right click on it and select Send to >> Compressed (zipped) folder. If posting the file in your private thread simply attach the .zip file in your post. If emailing to your tuner simply attach the .zip file to your email. SEND ONLY .ZIP FILES! NEVER SEND A .CSV FILE!!!!


The following are the absolute minimum PIDS you should datalog:

TP = Throttle Position Voltage
IEGO1 = Hego 1 Voltage

If you haven't dialed in Fuel yet then be sure to log these:

iMAF = Mass airflow sensor raw voltage
LAMBSE1 = Bank 1 Lambse
PERLOAD = Engine Load Percentage
ECT = Engine Coolant Temperature
FUELPW1 = Injector PulseLength Bank 1
KAMRF1 = Fuel Correction Bank 1
ATMR1 = Engine Running Timer
Note: IEGO2, LAMBSE2, FUELPW2, KAMRF2 can be logged if more than 1 hego is controlling fuel.

If you haven't dialed in Idle Air yet then be sure to log these:

ISCDTY = ISC Duty Cycle
IPSIBR = Instantaneous Idle Airmass Correction
DSDRPM = desired idle rpm commanded

if you haven't dialed in Spark yet then be sure to log these:

LOAD = Calculated VE
SAFTOT = Actual Spark Advance
ACT = Aircharge Temperature

If you haven't dialed in Transient Fuel yet AFTER dialing in fuel then be sure to log these:

EFTRFF - Transient Fuel
AEFUEL - Accel Enrichment Fuel

Generic Payloads

VBAT - battery voltage

Trans Tuning Payloads

TV_PRES - TV Pressure
SPD_RATIO - trans slip ratio
BCSDC - tq converter clutch duty cycle

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