I was wondering if anybody knows the correct way to MAF tune? It will have to be without the wideband hook up to hpt. I wont be able to get HPT Pro anytime soon. I read this on the hpt site: "You need to plot the LTFTs against the MAF table using a histogram. Then just copy and paste special (multiply by %) the percentages into the tune. Flash and repeat.".. Is this a correct way of doing it? My VE table is great and just need to MAF tune. Any help would be great!

 

I have always done STFT+LTFT histo against the maf and it works fine.

Also you dont need pro to have your HPT log your WB.

 

ok so instead of just the LTFT against the maf put LTFT+STFT pid against it? How do you log your wb through hpt then? Is it that a/c switch mod or something?

 

Yes LTFT+STFT Trim error vs. maf freq.

If you do just the LTFT you are just going to have to do the STFT too..

And yes through the ac pressure signal wire. Mine works perfectly...

 

you have any kind of wiring diagram? Is it easy to do?

 

Follow the HPT thread on it in the I4, I5.... There is a picture of what wire to splice into.

 

you have the link? i cant find it on there, even when i do a search lol

 

nvm found it

 

any know a good way to maf tune? I got my afr wired though the ac switch so i can log afr's now. Or at least point me in the right direction with a link or something. Thanks

 

cruise, maf error histo, copy, paste with multiply % - half, flash, repeat hand smooth when necessary

 

ok, thats what i've read. My buddy tunes a lot with hpt and told me something a bit different. Taking the difference from actual afr and commanded afr then multiply % to the maf

 

anyone know the function string for AFR error?

 

100*([sens.120]-[sens.121])/[sens.121]

 

yeah i found it on hpt... (actual-Theoretical)/(Theoretical)

 

so i've been MAF tuning lately and seems to be going nowhere? Do i need to reset my fuel trims or something? I have a histo setup for AFR error against the maf and every time i go for a log i seem to be getting the same numbers (-1.17) pic is posted below. After I'm done logging i go into the editor and paste multiply % against the maf. Seems for the past 4 logs i keep getting the -1.17 in those cells every time. Is this just a matter of taking awhile to smooth out?

As for the histo, I'm using my ac switch to log AFR's. This is the equation I'm using for the histo: ((([PID.7101]/(5/8.5))+10)-(100*([USER.7101]-[SENS.121])/[SENS.121]))/(100*([USER.7101]-[SENS.121])/[SENS.121]).... Basically (Actual - Commanded) / (Commanded)

 

you need to turn off as many modifiers as possible. Disable DFCO and fuel trims. Also there is a good write up what to do to get as accurate as you can while fuel tuning. The fuel trims are making your AFR 14.7 while cruising and idling and that is why your afr error histo is reading so close to 0. When you disable all the modifiers it will take all that crap out and run on exactly what is commanded and thats when you make your changes.

 

I just turn off DFCO and turn off closed loop in the scanner instead of doing it through the tune.

OP your car needs to be at 0 STFT's and LTFT's while its running, that is basically how you know that the car is in open loop. Reset the trims every time.

 

where is the DFCO in the scanner? Been looking and cant find it. So just turn both those off, reset fuel trim, log, then edit tune?

 

DFCO has to be tuned out. Sorry I wasnt clear. Under fueling DFCO put all temps and rpm to max.

Put in open loop through scanner, reset fuel trims, turn car on, log, correct tune with paste special %... repeat until within 1% or whatever you are comfortable with,

 

ah gotcha, so just set all those values to something you will never reach.. I will try that out tonight

 

yup..

 

cool, i'm gonna be heading out here soon. Cruising around with my buddy, i'll let you know how the logs come out. Thanks man!

 

wow this is getting annoying i did exactly what you said.. here is what i got, also attached is my tune.. The whole time i was driving when i was on the throttle, whether 1% or whatever the afr pegged to 10..


DFCO disabled





This is what i got

 

I have the new beta and this works but I set my AFR Error like this:

100*((USER.xxxx-14.7)/14.7)

USER.xxxx represents the custom AFR PID.

I could not get the built in AFR gauge to work...

Just be patient I couldnt get mine to work for months. haha

 

Where do I get the new beta? I've been looking and can't find it.