Contour Enthusiasts Group Archives Forums Modifications 3.0L Duratec lol 10:1 a/f ratio

Originally posted by DemonSVT:

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Originally posted by warmonger:

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1. Going rich on decel is normal because you are cutting the air off before the pcm cuts the fuel.
2. Best just to tune your WOT fuel curve by adjusting the MAF transfer function until you are in the recommended limits and then let the computer take care of everything else.

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1. Maybe for a brief split second. The PCM turns off the injectors on decel so in reality the engine goes flat lean almost instantaneously.

2. That's the incorrect way to tune if you mean trying to tune WOT with just the MAF function. In reality that's as bad as hack tuning with a MAF voltage altering device. It screws with the load tables & nearly every calculation done by the PCM. (i.e. you get an erratic tune)
You should set the MAF function to match the curve of the MAF's electronics. (give or take some very fine tuning to match you intake setup) That's how I built your MAF Function Tom and you seem to be happy with it. (I still have the spreadsheets around here on my computer I bet)
Your actual tuning should be done using the fuel tables just like how the PCM is suppose to work. If all your other settings are done correctly (that's a big if, if you are not self tuning btw!) your fuel base tables should match your final A/F +/- a few percent. I know mine do. Good luck tuning like that on a WOT dyno because you really can't do it. You can definitely hit WOT A/F numbers but if the other A/F numbers are off it will cause everything else to slowly drift. This all goes back to a properly designed MAF curve to match your MAF and intake setup.

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That's the whole POINT. Damn you can really choose the wrong interpretation when you want to.

Oh, and let me just point out that the current MAF function I'm using is not the one you built, but thanks for helping me with the original.

The whole point is that most people can't tune the base tables. As long as the MAF transfer function is inputted correctly then the computer will get you close to what is desired. It won't hurt a bit to rescale the function a few percent to change the A/F curve. I doubt it would significantly affect the load calcs with a few percent scaling.
The difference between 12:1 and 12.7:1 is only a few percent. You are just dead wrong about being able to tune like that. BUt hey, that's not your fault since you've been spoiled by having a tweecer this whole time. <read spoiled> You have the ability to tune the way it was intended and that is great.

Just don't forget where you came from. YOU ALSO used a damnn SAFC (aother cheap MAF scaling device) back in the day before you got a tweecer, just like the rest of us back when there was no support for our platform. Back then you were saying it was a good thing........