Air/Fuel Ratio Question

[DenisN]

Hi everyone!

I have eco boost mustang 2019 year.
Only 14 000 km.
First I did is changed f sensor on new (revised) with CA at the and.
there were not any issues with old, did it only after recommendations ect
First 3 000 km AFR was 13.9-14.2 on XX.
But when wether is cold, AFR is from 13.8 - 14.4.
It is do not depend on heat c temperature, the same on cold and heat.
What is the reason…?
Should I bothering??
In general, motor working smooth.
Many thanks!

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[EFI]

But when wether is cold, AFR is from 13.8 - 14.4.
It is do not depend on heat c temperature, the same on cold and heat.
What is the reason…?
Should I bothering??
In general, motor working smooth.
Many thanks!

Sounds normal, it will fluctuate a bit more when it's cold.

 

[engineermike]

@DenisN your car targets 14.08 at cruise whether hot or cold. If you want to dig any more, log your long and short term fuel trims. Less than 5% total at cruise is ideal and would indicate it’s working perfectly.

 

[DenisN]

Thanks!

 

[RaceRedCaliSpecial]

What about coming to a stop light and the AFR stays at 12.4 for a minute or two before jumping back up?

 

[junits15]

What about coming to a stop light and the AFR stays at 12.4 for a minute or two before jumping back up?

normal.

 

[Angrey]

What about coming to a stop light and the AFR stays at 12.4 for a minute or two before jumping back up?

The Ford tune uses several parameters to try to maintain target idle rpm, AFR, timing, TB angle, etc. And it has different tables/strategies for torque when the A/C is on and off.

It's actually quite annoying when trying to dial in a wild setup with ginormous TB, huge injectors, etc. It's like playing a game of whackamole.

 

[K4fxd]

I know it is 100% safe to run Stoich on modern engines, it does save fuel, but I run mine at 13.9 AFR as the base.On the old carbs I would target 13.0 at idle, cruise and decel.

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