Ford Fiesta ST, Focus ST, and Mustang EcoBoost – Data Logging Overview


The Accessport for your Ford EcoBoost is a powerful tool. Aside from being able to flash the ECU with different tunes, and a diagnostic tool able to read and clear codes, it can also display and record hundreds of different parameters.  From Ambient Air Temperature to Vehicle Speed Sensors and everything in between, the Accessport will be able to provide you with the data you need.  This post will discuss how to record a datalog, which monitors are most important, and what all these numbers mean.  Being able to interpret these parameters can ensure your engine is running healthy and achieving its performance potential.

Every Accessport is automatically setup with a default log list.  This list of parameters will help troubleshoot the most common issues of the specific vehicle with which the Accessport is used. Here is a link to the Full Monitor List which defines each monitor.  That’s quite a few!   Having an in-depth knowledge of how your engine works, and the affects added modifications have, allows troubleshooting of more complex issues.  Luckily, an in depth knowledge isn’t required for a basic wellness check.  Below are some of the key monitors that can help determine you engine’s overall health.  If you’re unsure of how to gather the data from your vehicle, check out COBB U Episode 17 covering how to data log.

After you’ve recorded your data log, it will be time to examine the results.

 Top Monitor List

The most critical to make sure the car is healthy and performing well are Ignition Correction and Octane Adjusted Ratio.

Ignition Correction can be monitored or logged through any specific cylinder or even all four. Positive corrections are ideal and negative corrections could potentially indicate an issue. Major negative corrections can be associated with feedback from the engine’s knock sensors. It should be noted that small corrections are expected and normal, but, if you are routinely seeing negative corrections beyond -2 degrees during WOT (wide open throttle) conditions, there is likely a problem.

Octane Adjusted Ratio (OAR) is a Ford calibration strategy that allows for optimal power with higher octane fuels (and also allows your car to run 87 octane without hurting anything). OAR starts life at a value of 0.0 (-0.75 on the latest map revisions) and is allowed to learn in two directions. When fuel quality and knock sensor feedback are optimal, the OAR will adjust towards -1.0. When these are sub-optimal, the OAR will adjust towards +1.0. Constant positive timing corrections will keep the car happy and bring the optimal value more quickly. 6th gear on freeways with partial throttle is a great way to help the value. If you monitor in this situation, you should see OAR approach -1.0 each time you lift the throttle. Continue to do so until it gets to -1.0 for optimal performance.

There are several other monitors that can be utilized and are up to your personal preference. Boost is always fun to monitor. Seeing certain variables before and after modifications is a great indicator of whether they are providing real results. For instance, being able to monitor both Ambient Air Temperature and Charge Air Temperature and comparing them in real time is revealing. You can see just how much more efficient that new FMIC is compared to your stock one! Monitoring/Logging Airflow Mass can also be indicative of whether that new Intake is doing work!  A greater value for this parameter indicates greater airflow.

COBB customer service is among the best in the industry. If you need help taking or interpreting your datalog, or trying to diagnose an issue, send it to us and we’re always happy to take a look and point you in the right direction.  Just email or give us a call at 866-922-3059.

Makis Sigalas on October 8, 2017 says:

I have updated my Accessport to the latest version a couple of days ago. In the past, when I was datalogging, I could easily select 24 data monitors suggested by my pro-tuner (Adam Brunson).

Today I was planning to datalog in order to send the data to my pro-tuner and I tried to select the same 24 data monitors that I have selected in the past. However I get the message “Too many monitors are selected. Reduce number of selected monitors and try again”.

Can you please let me know what the problem is? Have you reduced the number of data monitors that we can select for datalogging?

Looking forward to your reply.

Thank you

Makis Sigalas

    Marshall on October 9, 2017 says:

    Hey Makis, we recently addressed an issue in which the data size/type was being calculated incorrectly when selecting monitors for Gauges or Data Logging. There may now be instances in which fewer monitors will need to be selected.


Andrew Camarda on August 6, 2018 says:

Any new progress in tuner development for the 2018 6sp ecoboost mustangs yet? Has Cobb begun R&D? Trying to hold off buying your competitors version. Let me know if you have an approx. release date. Thank you.

    Kyle on August 6, 2018 says:

    Hi Andrew,

    Support for the MT cars is nearly complete. However, we release support in model years so the model year 18 10 speed AT cars need to also have a solution. This is causing the longer delay for support. We have a good candidate for an OTS map at the moment and are in the final soak/testing. I’m hesitant to give you an ETA as anything can come up during testing but I will say it shouldn’t be too much longer.