Question about A\F ratio.

[GHIG'13]

I just put in my aeroforce gauge and its working fine. My question is that while monitoring my a/f ratio I have noticed that if I let off the gas and let the car decel in gear that the a/f pegs out at 28.11 and will stay there until I clutch it. I am pretty sure this isn't really good for the motor, but realized I never did that while datalogging for my tuner. Should I let him know or is it ok? Thanks guys.

 

[manolith]

While engine braking to save fuel this motors cut out fuel. That's what I saw on a magazine article about the coyote when it first came out. I would imagine that the a/f ration would be quite high under those conditions. But it shouldbt harm anything because cylinder presures are low in those events.

 

[125oh]

My aem does the same thing . At wot it will read 12.6 then when you get out of it , it leans way out . Its normal I'm pretty sure . Your data logs should show it also . Thats why it will show a max of 2.00 lambda cuz when you get off of it it goes way up . I might be totally wrong but the wide band is reading the mixture of burnt fuel and oxygen in the exhaust , well when you let off from acceleration there is no more burnt fuel being measured therefor a lean condition . Like I said I could be way off as I'm trying to learn all of this also . Hopefully someone else will chime in

 

[GHIG'13]

While engine braking to save fuel this motors cut out fuel. That's what I saw on a magazine article about the coyote when it first came out. I would imagine that the a/f ration would be quite high under those conditions. But it shouldbt harm anything because cylinder presures are low in those events.

My aem does the same thing . At wot it will read 12.6 then when you get out of it , it leans way out . Its normal I'm pretty sure . Your data logs should show it also . Thats why it will show a max of 2.00 lambda cuz when you get off of it it goes way up . I might be totally wrong but the wide band is reading the mixture of burnt fuel and oxygen in the exhaust , well when you let off from acceleration there is no more burnt fuel being measured therefor a lean condition . Like I said I could be way off as I'm trying to learn all of this also . Hopefully someone else will chime in

Thanks guys, I was thinking I had read that somewhere but wanted to make sure. The car only has 675 miles on it and the Paxton has only been on it for a week. Didn't want to take any chances.

 

[NoSlo5oH]

That's normal. I have a '13 with the track package and my a/f gauge pegs out at 20.0 during deceleration.

 

[GHIG'13]

That's normal. I have a '13 with the track package and my a/f gauge pegs out at 20.0 during deceleration.

That makes me feels a lot better. Really trying to become more informed on these motors. Thanks man.

 

[Cashbum]

As they've said before me it's a fuel decel cutoff thing. No need for gas when coasting and won't hurt anything either

 

[KonaFifty]

It is not just these motors, every motor should do this. My last 2 Evos did the same thing.

 

[Torchy]

If ya want to get technical it's called ADFSO (automatic deceleration fuel shut off)

Ford puts this on most/all of their vehicles in their line up. It's purely there to help fuel economy and doesn't hurt anything.

 

[mebcop]

My srt4 did this also. My buddy's STI did too. Very common. You'll notice when talking to tuners that they mostly only care about WOT a/f ratios. The big thing for a while on srt4's was that people were leaning out their cruising A/F's to like 15.5-16.0 and getting better mileage with no negative side effects. Its not like u have super high cylinder pressures at cruise.