Sale ends todayGet 30% off any course (excluding packages)

Ends in --- --- ---

MAF sensor placement and effects on tune

Practical Reflash Tuning

Forum Posts



Tech Articles

Discussion and questions related to the course Practical Reflash Tuning

= Resolved threads


Flash tuning Mazdaspeed 3 with COBB accesstuner.

Switching to the COBB SF intake, which is simply a better flowing, similar diameter intake compared to OEM, I am noticing some phenomena that I am struggling to tune around.

I believe this is caused by the MAF placement.

1. I seem to be chasing my tail trying to set the MAF calibration, I have 2 consecutive RPM sweeps showing different trims. 1 sweep may show -3% and the next +3 at the same MAF V position. The variables that are changing are RPM, gear and engine load - Should these influence fuel trims?


2. When under low load cruising (throttle pretty much closed), It seems like the car is reporting between rich/lean condition, and the system is responding appropriately by pulling or adding fuel, up to the 25% limit. See the yellow line(AFR), in the following picture. The system will swing between 13-17AFR. This is felt in the cabin (unsteady due to extreme lean/rich miss).


From my research, I believe this has to do with the MAF sensor placement on the intake:


With an air straightener that I normally don't see:


I want to believe that COBB is a reputable company and they know what they are selling, but this design with the MAF sensor right at the filter goes against what I know and research. It is enough to function, but could it be the reason behind what I am seeing?

Thoughts?? Opinions??

Attached Files

Hello im with you on this one i would be adding some pipe to the air cleaner area too prove a point

regards Ross

We usually reply within 12hrs (often sooner)

Need Help?

Need help choosing a course?

Experiencing website difficulties?

Or need to contact us for any other reason?