LeftySS

iTrader: (17)

I am using hptuners on a 99 camaro and i don't understand why i am running so lean at wot. I think i have my ve and maf dialed in using stft. all cells in ve are -3 to 2, feel that is close enough if running a maf. maf stft's are mostly
-2 to 1. have a wideband and am scanning that and i am getting readings that are very lean for what i am commanding in pe. 14.86/1.250 should be 11.88:1 why am i getting 13.6:1 readings. don't get it!

caliswangin916

iTrader: (3)

my stock pe tables is 1.250 which is 11.8 but i would always see 12.5 in wot.
i would tune the ve to be always negative so when you go into pe/maf/or whatever table to control for addition of fuel.

i think it is in your maf tables, maybe OLFA, and or spark that's causing the lean wot. try bumping maf up 5% in the higher hz such as 8875+.

what are your mods?

LeftySS

iTrader: (17)

ok- so maf is not telling the pcm the right amount of air is going in at wot. is there a way to scan while in wot to find out the right amount of air going in? or am i just going to have to scale it until i get the commanded fuel that is in pe? car is an A4.

Mods: lid, k&n, free ram air, 160 stat, slp lt's, catted y-pipe w/ dynomax bullet and borla cat-back, 3.73's, hot cam

ZL1Killa

iTrader: (17)

set your PE mode tow what AFR you want to get and increase your VE table to get your fuel trims down. your also going to have to look at your Open loop fueling table, the car is 'supposed' to take the richer of the two; for some reason caliswangin916 is having some issues with this as well....which i still haven't figured out

i never messed with my MAF numbers

LeftySS

iTrader: (17)

so should i just leave the maf stock even if i have ported ends? I do have a wideband but not sure how to set it up to do aft% error.

LeftySS

iTrader: (17)

I thought that above 4000 rpm the car just uses maf to do fueling?

caliswangin916

iTrader: (3)

i've never been in OL on any of my scans according to the scanner. in what i thought would be pe or maf or both was not the case because when i needed fuel in the the higher rpm cells, i would add to ve to fix the LTFT.
to get afr to what i wanted, i increased the maf table across the board by 5%, then adjusted for individual cells adding and subtracting a guess number.
this is working out for me fine.
but when after the maf tune i adjusted ve again, i got the same problems as before only now with maf/ve tables whose values are higher.

look at your OLFA table, the higher map vs ect cells are 1.13 which is 13.0 afr. even though my scanner said i was in closed loop, i believe that this table was controlling my fueling. i changed mine to 1.17=12.5 afr and i get this afr now until some other table kicks in that brings my afr to 11.8-12.1 in higher rpm/maf cells. i don't know what tables is doing this but i believe it's maf kicking in .

i don't know when pe is used but don't believe that it is used that much nor overrides other tables since stock value is 1.250=11.7 afr of which i've never seen happen in wot until i tweaked with my maf/spark/olfa tables.

* i don't know how to tune so i'm just typing my experience.

LeftySS

iTrader: (17)

Well from my understanding the only time you are in open loop is when closed loop is disabled and on inital startup, for enrichment. any other time the OLFT is not accessed and used in any of the fueling. I have been in closed loop the whole tuning process using STFT's to dial in my VE table under 4000 rpm. I then scanned STFT against my MAF vs. Hz table all the way through the rpms. Feel good about my fuel trims with both the VE and MAF under 4000 rpm.

ok-so how do you tune MAF for the upper rpm ranges so the PE table will be accurate? With it working so it adjusts fuel trims? off so you just get a reading but not adjusting fuel trims? by stft's or Dynamic Airflow? and if by Dynamic Airflow in SD mode with the ve smoothed will the ve be close enough as to not run dangerously lean while scanning this? this is my main concern right now trying to get MAF dialed in. Have read alot about this and still not positive on what i should do

I have a wideband, but not sure how to set it up on hptuners to be able to log afr% error. Can anyone please explain how to do this or is it already on there i am just not seeing it?

Frost

iTrader: (45)

Those MAF ends SCREW UP the MAF cal quite a bit, usually driving trims way positive (+12 to +16 almost everywhere depending on other mods).



PE IS used to command WOT AFR, that's how most folks get WOT done on a dyno actually... Unless it drops below 1 (stoich specified in your tune) it is acting on WOT. If your whole pull is 13.6:1 (straight line, not likely, but easy to use as an example here) and you desire 12.8:1, multiplying all PE numbers by 1.0625 (actual/desired) it will be DAMN CLOSE at WOT. People will jump up at this and say no, you need to fix your VE/MAF, and they aren't wrong for saying that. That is why you are not seeing commanded AFR in PE and the method I described is believed by many to be "incorrect"

LeftySS

iTrader: (17)

Here is another question. PE is a divider into the stoich afr 14.7:1. So wouldn't it be wise to say that the VE and MAF are originally calibrated to give you the 14.7:1 afr in all rpms and maps? Other wise how would PE be accurate all the way through if it wasn't?

LeftySS

iTrader: (17)

Could you in theory? Turn off all fuel multipliers mainly PE, scale the MAF up 20% or so, turn off all closed loop operations, scan MAF vs. AFR% error to 14.7:1 all the way through rpms, then turn closed loop and PE back on and have it pretty close at WOT? And is 14.7:1 a safe enough AFR at WOT to tune for before multipliers? Will the motor blow up on me? I know it is lean but is the only way i see PE being exactly what you command it to be..

caliswangin916

iTrader: (3)

stock pe setting is 1.250 across the table which is 11.7 afr. i have never seen wot at 11.7 prior to changing maf,spark,ve,olfa. all stock and before any tuning, i was at 12.5 in wot na or on a 40 shot.

after injectors, i was at 12.5 na and 12.6-13.1 on the 40 shot. that's why i think the pe table wasn't being used.

caliswangin916

iTrader: (3)

people have seen upwards of 14.7 in wot but probably unintentionally. myself, i would let off the gas if i see 13.8-14.0.

Frost

iTrader: (45)

If this is the resulting AFR after doing all of that tuning, you have done something wrong along the way or are just not finished.

If you think the PE table isn't being used do this: set it all to 1.5 and log your wideband at WOT

Doc

iTrader: (9)

I agree. x2

caliswangin916

iTrader: (3)

i said prior to any tuning the stock 2000 pe table is set at 1.25 which is 11.7 afr if stoic is commanded at 14.62.
i've never seen 11.7 at wot nor in supposed pe parameters which are before wot because the tps settings for pe are not 100% tps. all i had besides a fullt stock car was a lid. i checked my original start tune with other same year, auto tunes from from the repository and did not see any differences in the stock tunes.

Frost

iTrader: (45)

I'm not really sure what you are sying here... but the car is not ever going to hit commanded PE if it's untuned, regardless of whether it is stock or not. My point is, if you think the PE table isn't used, seriously, try what I said above and log and watch your AFR hit the floor. For *****-n-grins, right now, if your AFR is steady at WOT, and is something like 12.0:1 and you want 12.8:1, divide 12.0/12.8... yields 0.9375. If you multiplied your PE table by that number (again, assuming it previously held constant through the rpm range, which it probably does NOT) your new WOT AFR would be REAL DAMN CLOSE to 12.8:1.

Experiment; try it out and see. What are you getting at WOT now as far as AFR through your RPM band?