[STirish]

Hey Guys,

I have been attempting to re-calibrate the MAF signal for my APS intake. After a few attempts it seems I can't get much better than .8%-4% on the A/F learning depending on the voltage range. .8% doesn’t seem too bad, and it seems to vary a little. What have others results been when attempting to calibrate the MAF signal for their intake?

I should have paid more attention when the car still had the stock intake.

Thanks,
Rob

[daemon]

I have never (in my one month of tuning one car worth of experience) seen a learned value of exactly 0.0, FWIW. I'm not sure if others have. My guess is less than 1% is A-OK. Climate variations will likely cause it to adjust as well, so I don't think it will ever be consistently perfect (unless you live in San Diego ).

[STirish]

Originally Posted by daemon

I have never (in my one month of tuning one car worth of experience) seen a learned value of exactly 0.0, FWIW. I'm not sure if others have. My guess is less than 1% is A-OK. Climate variations will likely cause it to adjust as well, so I don't think it will ever be consistently perfect (unless you live in San Diego ).

Lol...San Diego sounds like a good place to live if you're nwe to tuning like us

Have you seen your A/F Learning values during cruse become stagneate at a specific value such as 3.0% or somewhere around the 1.0%-6.0% range? The ECU seems to keep that value no matter what you change the Intake Cal Map at the appropriate value to, within reason.

[daemon]

My values were always negative. Largest magnitude I logged was about -4.x. But I was constantly reseting the ECU due to other adjustments. I realized it was taking a little longer for the AF learning to adjust, so I let it go a few days longer without other tweaks. That's when it made it to the -4 area. I have always been rich, so that wasn't too surprising. I spent the last few days making adjustments to the intake calibration and think I am almost perfect for my weather conditions. I need to let the car run as-is for a while without a reset and log some more to be sure though. My WOT AFRs are much much closer to my fuel map now. I'll have to do a round of logging in the winter to see if my current intake adjustments keep me respectable in the lower temp/humidity.

The AF learning will change if you make changes to intake calibration. It just won't usually happen instantly and there is a little bit of a data resolution issue I think. You need to drive around for a few days, making sure to cover a decent RPM range under closed loop conditions. For my adjustments, I've pulled my intake cal numbers by a multiplication factor ranging from 0.95 to 0.965.

[STirish]

I have just about given up on the intake cals on the high-end and will probably let the ECU do it's thing in the low-end. I have spent close to 30hrs trying to get my intake cal curve smooth and corrected for my intake. At this point I'm going to leave things alone and just change the primary fuel map to get what I want. The load curve is just not as smooth as when using the "stock" intake cal curve no matter how much time I spend on it. I may try the stock intake to see if my load curves further smooth out. Smooth load == rock solid AF curve.

Some people have an oral fixation, I have value fixation and it's bad for tuning, as things seem to turn for me. It's time to try a very different and hard approach (for me anyways), just changes the values listed to make the motor happy. I have been infatuated with trying to get the values in the ST to match the outputs. Empirical values are out the window ; - )

[daemon]

Certainly takes time. You really need to set it and drive for a good amount of time before relogging and adjusting. I used excel and graphed the stock curve, then smoothly applied my adjustments over the cells. Then copied it back into ST. So far so good. Think I am almost where I am happy.

[STirish]

Originally Posted by daemon

Certainly takes time. You really need to set it and drive for a good amount of time before relogging and adjusting. I used excel and graphed the stock curve, then smoothly applied my adjustments over the cells. Then copied it back into ST. So far so good. Think I am almost where I am happy.

I'm guessing you are more talking about voltages of < 3.4v?

Do you have any MAF or Load curves that I could look at for comparison? I may be too picky. What are the typical deviations you see in your AF curve during a 3rd or 4th gear WOT pull? When I have my Intake cal curve corrected and very smooth, the load curve has small "notches" in it. Granted the stock intake cal curve does also, but not as bad.

I have been making modifications to the cal curve in excel and lots of real-time tweaks. Fun, fun, fun...

When modifying the Intake Cal curve for the higher voltages, is it really necessary to let the ECU learn. From what I have seen, the ECU goes with what it is given as far as a MAF voltage.

Thanks

[daemon]

All ranges. Basing my low end of the curve changes based on the AFR learning and then when those learning numbers are solidly consistent as far up the curve as I can get in closed loop, I then make "eyeball" adjustments to the top end of the curve based on wideband readings.

[STirish]

Originally Posted by daemon

All ranges. Basing my low end of the curve changes based on the AFR learning and then when those learning numbers are solidly consistent as far up the curve as I can get in closed loop, I then make "eyeball" adjustments to the top end of the curve based on wideband readings.

Ok, in closed loop you’re waiting to see what happens with the long term and closed loop your going off of your error from requested AFRs vs. the wideband readings. We’re doing the same thing. So how close to your requested AFR are you getting on open loop and what is your error along those points? I'm really hoping to see if your results are similar to mine, otherwise I'm a data point in the middle of nowhere.

Sorry, I’m really frustrated right now and am just hoping for a little comparative data.

[daemon]

I assume you mean open loop the second time you say closed loop. But yeah, since the ECU applies some closed loop learning during open loop, it is hard to nail down to top end until you have the closed loop part pretty solid. I'm still not done and I have temporarily removed my wideband until next week so I'll see where I'm at then after some driving. I'll be happy to post my curve when I'm satisfied. Until then it is still a work in progress. But last time I checked was within .5 or better of my WOT targets. If my closed loop tuning was off a bit then that number will drift by next week, but I'm confident I'll be happy with it then or with one more round of adjustments. I actually want it to be at least .2 richer than my map up top as a little safe gaurd for weather variations, or maybe more for psychological reasons.

[jays05]

I really think that the only way to rescale the MAF properly (without spending a ridiculous amount of time) is to copy/paste the MAF scaling values out of ST and into a spreadsheet program like MS Excel. This is what I did for my Injen CAI.

From looking at the A/F learning, I knew that I needed about 15% more fuel on the low end. From looking at my wideband O2 readings at WOT, I knew that around 4.4v on the MAF I needed about 5% more fuel. So I copy/pasted the MAF scaling out of ST and into MS Excel. I made a simple formula that tapers the amount of fuel(airflow through the MAF) to add, so I get a smooth transition from +15% on the low end to +5% on the top end.

This gives you a nice smooth curve, and after looking at your logs you can say "OK let's try adding another 1% fuel on the top end" without worrying too much about the actual values in the cells. Just plug in a new value in the spreadsheet, then manually enter the values from the spreadsheet into ST and try again.

If anybody wants the spreadsheet, PM me your email address and I'll send it to you.

[daemon]

That is exactly what I am doing. But I'm on the edge of being a perfectionist and I'm taking this very slow on purpose.