Jpr5690

iTrader: (13)

I WAS PLANNING ON STARTING MY SD VE TABLE TUNEING BUT WANTED TO KNOW HOW TO DISABLE PE MODE (ALSO, I READ I SHOULD DISABLE PE MODE BUT WHY AM I DOING THIS)

FINALLY JUST TO RECAP ON THIS PROCESS.. TO TUNE YOUR VE TABLE YOU ..

1: UNPLUG MAF
2: SET MAF FAIL FREQ TO ZERO
3: COPY HIGH OCTANE SPARK TABLE TO LOW OCTANE
4: RESET FUEL TRIMS IN HPT SCANNER
5RIVE AND LOG HISTOGRAM 4 (LTFTVS ENGINE SPEED VS MAP)
6: TAKE THE AVERAGE VALUES PER CELL AND ADD THEM TO VE TABLE IN THE EDITOR

AFTER ALL THIS UNDO STEPS 1-3 RE RESET MY FUEL TRIMS AND MY CAR SHOULD NOW TRIM 0

MY QUESTIONS ARE..

1. DOES THIS HAPPEDN RIGHT AWAY OR DO I HAVE FOR ANOTHER 50 MILES TO GO BY TO SEE THE RESULTS OF THE CHANGES OF MY VE TABLE SHANGES

2. WHY ARE THE EFFECTS IF I DECIDE TO TUNE THE ENTIRE VE TABLE (NOT JUST BELOW 4000 RPMS

AND AGAIN,

3.HOW TO DISABLE PE MODE?
4. WHY SHOULD I DISABLE PE MODE (AS IN WHAT HAPPENS IF I ENTER PE MODE WHILE LOGGIN MY TRIMS)

rush7

iTrader: (2)

I'll answer how to disable PE mode. The way I do it is set every point in the Power Enrichment vs RPM table to 1.00. In that way you will actually be entering PE mode but it will have no effect on your air-fuel mix (it should try to maintain stoich).... I'm not sure if you have to turn PE off if you are tuning without a wideband, however. Someone else might want to field that one. Or look at the tuning document in the sticky at the top of the forum.

I have tuned parts of my VE over 4000, but I don't know if that has any negative effect or not. It hasn't seemed to.

oange ss

iTrader: (50)

safer to set PE to what you want, set OLFA table to 1.00

Jpr5690

iTrader: (13)

Olfa?

Jpr5690

iTrader: (13)

THE ENTIRE CAR WAS MAILORDER TUNED BUT I DO NOTICE MY LTRMS ARE -12 HELL ACTURALLY THE CAR JUST RUNS RICH PERIOD EVEN WOT IS A LITTLE RICH

I FIGURE ILL START BY CORRECTING MY LTRIMS BUT I REALLY DONT WANNA MESS UP MY WOT TUNE

WILL CHANGING MY VE TABLE AFFECT MY A\F FOR WOT OPPERATION?

oange ss

iTrader: (50)

Open Loop Fuel Air..dont worry about then, make sure COT is turned off

Jpr5690

iTrader: (13)

Cot?

And Why Shouldent I Worry About Olfa Now?

oange ss

iTrader: (50)

Catyltic Converter Overtemp....if you're just messin with part throttle then you dont need to mess with it

Jpr5690

iTrader: (13)

ok cool! hey i have no cats so im guessing this was turned off with my last tune because it was done professionally

Jpr5690

iTrader: (13)

Also Are The Ltft Values Worthless If The Car Is Using The Maf Still .. Basically I Dont Understand Why You Must Disable The Maf To Log Your Ltfts?

oange ss

iTrader: (50)

not to log to tune VE,without turning MAF off, the LTFT could be a mix of VE and MAF...therefor tune VE, then tune MAF table if needed

Jpr5690

iTrader: (13)

Ok So Im Guessing If I Unplug The Maf And LoG The Ltft Then Adjust My Ve Table Ideally It Should Read Zero... But If My Maf Is Also Off Then It Could Make My Ltft Read Off Again

So To Verify That My Corrections To My Ltft Were Sufficent Could I Log My Ltfts Again With My Maf Still Unplugged And They Should Read Zero???

Then If After That I Plug My Maf Back In And The Values Change Then That Would Be Showing Errors In My Maf Table?

98Z28CobraKiller

iTrader: (17)

It's going to take you more than just one log and correection to get the VE Table in the 0 to -4 range that is desired. Make sure that you are 180* before you start logging or your numbers will reflect averages from the heating up period.

Jpr5690

iTrader: (13)

so i gotta do that procedure many times?

oange ss

iTrader: (50)

rinse and repeat as needed, be aware tuning by LTFT will get you close, but there are many variables that could skew them one way or another

silverTA2002

iTrader: (1)

See my thread about tuning above 4k rpms.

You tune using STFTs. No need to drive 50 miles between logs because LTFTs are disabled.

Jpr5690

iTrader: (13)

Ok Jason @ Tsp Said Not To Unplug The Maf And Just Tune The Ve Table With The Maf Influnceing The Ltfts He Said It Would Be Easier And Work So Long As Im Not Planning On Removing The Maf ...


My Understanding Is By Simulating A Maf Falure Im Going "open Loop" And Tuneing Based On My 02 Sensors.. Then After I Adjust My Ve Table I Will Have To Recaibrate The Maf Onlyif The Ve Table Is Is Off Once The Maf Is Pluged( The Idea There Is The Ve Table Should Be Correct Provideing No Influence From The Maf; Therefore Any Change In Ltft After Pluging Back In The Maf Must Be From Maf Calibration Errors??)

But At The Same Time To Adjust The Ve Table With The Maf Pluged In.. Is Just Masking Any Errors In The In The Maf Table By Compensating For The It With Ve Table Adjustments

Is This A Good Understanding Or Do I Got It Fucked Up?


Or Put Another Bay Ltft Are Determined By 02 Sensors Not Reading Proper A\f Ratio And You Ve Table Tells The Computer How Much Air Is In The Combustion Chameber (and How Much Fuel To Add) Your Ve +ltft Should = Proper Fueling Of Car The Maf Also Influences The Fueling Of The Car By Adjusting The Ammount Of Air Te Pcm Believes Is In Te Combustion Chamber

When Tuneing Mafless Your Car Basically Just Uses The Ve Table To Estimate The Fule It Needs And The 02 Sensors Correct It (ltft) So If You Get This Value To Zero Then Your Ve Table Accurately Represents The Air In Your Combustion Chamber But Now If You Plug Your Maf In And The Ltft Values Diviate This Means That Your Maf Is Disagreeing With Your Ve Table And Your Car Is Being Improperly Fuled Therefore You Must Re Calbriate Your Maf To Agree With Your Ve Table About The Amount Of Air Entering Your Engine

silverTA2002

iTrader: (1)

If you don't unplug the MAF (or set MAF fail frequency to zero) you can't correctly tune the VE table.

The MAF is off if you've modded ANYTHING that changes your airflow (lid, filter, intake, heads, cam.....).

And, you can't know how far it's off, unless you disable it, then tune.

Not uplugging the MAF would definitely be easier. It would also be incorrect.

oange ss

iTrader: (50)

you can leave everything connected and adjust accordinlgly, but you dont know where the errors are coming from , could VE or MAF, moslty MAF..etc... the point is to delete as many variables as possibly and tune each system to correct for any discrepancies

Jpr5690

iTrader: (13)

so the approach you all perfer is to tune the ve without the maf; get the ve to where the ltfts are really low with the maf unplugged and after than plug in the maf in and adjust the maf table to allow the ltfts to be back to the same values you had before the maf was pluged in (but after you tuned the ve table in sd mode)

is this the idea?