What's a "MAF Count"?

joethefordguy

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I'm completely new to tuning. I have an 04 Expedition police package with the 5.4L 2V; it's a 4x4.
I bought an SCT Livewire TS+ tuner in anticipation of the work I'll be doing on this truck; I want to improve low end torque and get better gas mileage - it's averging about 11 mpg over the last 10k miles.
I don't understand all the "gauges" my tuner reports. Can anyone tell me what the MAF count is counting? I do know what the MAF is and what it does, I just don't know what SCT is counting for this display. FWIW, I asked SCT. Here's my question to them, and their answer (in bold):
"MAF counts – Assuming this is the Mass Airflow Sensor, what is MAF counts telling me? Honestly I myself am not sure what the counts are. I do know that they go up and down with the amount of airflow past the MAF sensor."

so, Here I am. any input will be appreciated. thanks for your time.
jg

here's a picture of my tuner display:
upload_2021-6-7_17-22-43.png
 

joethefordguy

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while I'm on the subject, what's up with the lack of a vacuum readout? I know it's now call "manifold absolute pressure", but SCT claims they don't have it. Really? what's the ECU doing, making guesses?
 

DSG2003Mach1

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Maf counts is basically air flow across the sensor - how much air is going into the engine. I think it’s like 1080 and the maf is pegged - it can’t read any additional air and therefore stops adding fuel or assumes a failure and defaults to the failed maf table. With a stock setup not much to be concerned with. With custom or aftermarket intake piping it can help you identify turbulence due to placement near a bend (irradic counts).

I’m sure others can better explain

there’s not a whole lot you can do to help mpg.
 

decipha

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Micro-controllers cannot measure voltage directly. For a digital input a value equal to minimum voltage == 0 and a value equal to full voltage == 1. Hence there is nothing in between. Thus the ecu uses a 10 bit analog to digital converter with a 5 volt negative reference applied to the maf in order to read the maf voltage from 0-5v as 0-1023 a/d counts. The maf element is a thermister. The ecu tries to maintain the temperature of the thermister to a set temp. The more air that cross the element the more voltage is required to maintain the temperature. Hence the maf transfer which correlates airmass to maf counts (maf voltage).

All you have to remember is that ad counts /200 == voltage.
 

Mike Dj

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I'm completely new to tuning. I have an 04 Expedition police package with the 5.4L 2V; it's a 4x4.
I bought an SCT Livewire TS+ tuner in anticipation of the work I'll be doing on this truck; I want to improve low end torque and get better gas mileage - it's averging about 11 mpg over the last 10k miles.
I don't understand all the "gauges" my tuner reports. Can anyone tell me what the MAF count is counting? I do know what the MAF is and what it does, I just don't know what SCT is counting for this display. FWIW, I asked SCT. Here's my question to them, and their answer (in bold):
"MAF counts – Assuming this is the Mass Airflow Sensor, what is MAF counts telling me? Honestly I myself am not sure what the counts are. I do know that they go up and down with the amount of airflow past the MAF sensor."

so, Here I am. any input will be appreciated. thanks for your time.
jg

here's a picture of my tuner display:
View attachment 1706771
Ford Tuning - MAF
To convert MAF voltage to A/D counts, you just multiply the voltage by 205. To convert from A/D counts to voltage, just multiply the A/D counts by 0.00488.
 

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