a/f ratios help

[mazdaspeed32007]

i brought my car to the dealership for it smoking and thought it was the turbo seals. when i got it back from the dealrship from their "lookover" my a/f ratios were running around a 13.7 during light throttle and sometimes in the 12's. also was running a 12.2 under light throttle for some reason. the only changes in the surroundings was the trip to the dealer and it was super foggy and humid out and around 40. not sure what could be causing the random change in a/f but i dont like it and im not sure how abouts to correct this or well....anything. lol. any suggestions or thoughts?

edit. my a/f before the dealership were around a 14.3 under light throttle.

 

[AutoEuphoria]

Give it a couple of days, first. If it doesn't work itself out then disconnect battery, wait 15 minutes, reconnect battery, and try again.

What might have happened was they disconnected the battery to work on the car. That's a standard first step. That will also reset the ECU. So then when they connect the battery again and send you on your way the ECU goes through a bit of a "relearning" period, and that might be causing you to run richer than normal.

 

[Speed3Rookie]

From his post looks like he's running "leaner" than normal.

 

[AutoEuphoria]

A/F is Air over Fuel (mass ratio of air to fuel). Stoich is 14.7 units of "air" per unit of "fuel".

If you have 1 "air" and 1 "fuel" you have an A/F of 1

If you have 2 "airs" and 1 "fuel" (lean condition) you have an A/F of 2

If you have 1 "air" and 2 "fuels" (rich condition) you have an A/F of 0.5

The lower the A/F number, the more rich you are running as there is less air per unit fuel (or in a slightly better way, more fuel per unit of air).

Obviously the ratio isn't supposed to be 1 to 1...stoichiometric is 14.7 units of "air" per unit of "fuel" (units in mass...meaning for every 14.7g of air, you would have 1g of gas). In any case, the first number is always the mass of air that is being combined with 1 of the same mass unit of gas, so running an A/F of 12 means there is 12g of air per gram of gas, which means there is more GAS than there would be at a stoichiometric (balanced) ratio, which leads to a rich condition.

 

[mazdaspeed32007]

A/F is Air over Fuel (mass ratio of air to fuel). Stoich is 14.7 units of "air" per unit of "fuel".

If you have 1 "air" and 1 "fuel" you have an A/F of 1

If you have 2 "airs" and 1 "fuel" (lean condition) you have an A/F of 2

If you have 1 "air" and 2 "fuels" (rich condition) you have an A/F of 0.5

The lower the A/F number, the more rich you are running as there is less air per unit fuel (or in a slightly better way, more fuel per unit of air).

Obviously the ratio isn't supposed to be 1 to 1...stoichiometric is 14.7 units of "air" per unit of "fuel" (units in mass...meaning for every 14.7g of air, you would have 1g of gas). In any case, the first number is always the mass of air that is being combined with 1 of the same mass unit of gas, so running an A/F of 12 means there is 12g of air per gram of gas, which means there is more GAS than there would be at a stoichiometric (balanced) ratio, which leads to a rich condition.

a real easy way to think about it if you have an a/f gauge is when your in gear without touching the throttle and letting the car slow down...yiour a/f goes waaaaay up to like 20 because there is 0 fuel input. and then insert AUTO's more in depth explaination.

 

[Speed3Rookie]

Thanks for the schooling guys.