VE calibration

[trx2stroke4life39]

I know this has been beaten to death but i just want to make sure that everything i am about to do is correct. I am working on a 2001 silverado with a 4.8 and i am about to start tuning the VE tables.

So far I have disable the mass air flow sensor by set the value to 0, disabled the PE by setting it to 640, and copied the high octane table to the low octane table.

Next I will flash these updates to my tune I will warm up the engine then open the scanner and reset the LTFT then go for a drive and try to hit all the cells that I can.

If they are all below 10 I copy the table and add it to the main VE table in the tune.

Next i will go back and create another log and then take the STFT and add them to the VE table again until they are all about 0 in all the cells.

Then I will re-enable all the stuff that I disabled and my VE table should be pretty close.

Is there anything else i need to do? Or is there anything I did wrong, or should i do differently?

[S2H]

Do not disable PE

You log your wideband o2 and commanded AFR
Then plot the afr error
If you have to use stft then use it.. But you don't disable PE
Copy-paste special- multiply by % -half ( you can do Norma not half the first go round

Rinse lather repeat until you are happy
Which usually is never.. But when you are within +/- 4 you are pretty good

Make sure you have the cell hits required set to at least 10
Maybe more than that when you finally get down to the nitty gritty

You can't do WOT stuff without a wideband
Don't even try... I will reach thru the Internet and slap the crap out of you if you think you can...

If you have a wideband then you don't need to use stft for tuning
Turn them off for tuning and then back on after done tuning

[98Camarod]

Do not disable PE

You log your wideband o2 and commanded AFR
Then plot the afr error
If you have to use stft then use it.. But you don't disable PE
Copy-paste special- multiply by % -half ( you can do Norma not half the first go round

Rinse lather repeat until you are happy
Which usually is never.. But when you are within +/- 4 you are pretty good

Make sure you have the cell hits required set to at least 10
Maybe more than that when you finally get down to the nitty gritty

You can't do WOT stuff without a wideband
Don't even try... I will reach thru the Internet and slap the crap out of you if you think you can...

If you have a wideband then you don't need to use stft for tuning
Turn them off for tuning and then back on after done tuning

I can see that going down. What did the five fingers say to the face......slap!

[EaglePerformance]

Why not disable PE? Aren't you trying to get as many cells as possible reading 14.68? Once that has been done, the air flow numbers match what is actually going through, then the commanded PE, (once it is re-enabled), will be correct? Or is it, I'm guessing, that once the parameters for PE are reached, you massage the VE to get it to match the commanded PE? Not disagreeing with you, I've heard you have long arms, (as he backs away from the computer screen).

[mowton]

If you want, filter out PE with [SENS.121] >14.6, I think the fear is you could hit the need for PE by accident and run way lean, the filter will just not log it

Right?

[trx2stroke4life39]

Why not disable PE? Aren't you trying to get as many cells as possible reading 14.68? Once that has been done, the air flow numbers match what is actually going through, then the commanded PE, (once it is re-enabled), will be correct? Or is it, I'm guessing, that once the parameters for PE are reached, you massage the VE to get it to match the commanded PE? Not disagreeing with you, I've heard you have long arms, (as he backs away from the computer screen).

Thats what I thought that way I could get as many cells as possible.

I don't have a wideband so I didn't plan on doing any WOT yet, I am still trying to learn as much as possible and do as much as i can with out it.

Do I need to do the LTFT or can i do it all with the STFT?
Sorry for being such a noobie I just don't want to screw anything up.

[S2H]

when you do it with fuel trims its only accurate at stoich...
when you have a PE Cell its not gong to read correctly...
when the car enters PE its going to need a little bit different than the VE says...
in theory its supposed to be a 1:1 ratio.but its not....I've seen lots of people try to do a tune using the stft's only ad when you put the wideband to it...any cell that is in PE turns out lean...I dont know why......its just that way..

trims are great for Part throttle...non PE cells..
anything that enters PE is a high load cell and needs to be treated as so...
High load requires different fueling and spark
and technically I should say that PE is not just WOT.....again its anything considered High Load

you can set your PE TPS threshold different if you want...but if you look at it its set to different values across the entire RPM spectrum..its done like this for a reason...more RPM...More Heat...Higher Load

and besides...its only a few hundred buck to get a decent wideband(I highly suggest the NGK AFX)...I know some of you guys probably lost that much money at a casino last week or spent that much at a club buying drinks or gave it away to some stripper you had dreams about..or bought some new $7000 TV......
before you buy your next Mods...buy a Wideband...its an Important Mod


and If you are going to risk using STFT at higher loads...I wouldnt bother with the filtering...its going to lock at 0 anyways...
if you were going to filter I would suggest using the Commanded EQ ratio PID or the AFR Comanded AFR PID and then log it if it = stoch(1 for EQ ratio...typically 14.68 for Commanded AFR but you have to actually look in the tune and see what they set Stoich at...)

[98Camarod]

I have a question about that. Are you saying that the commanded afr is stoich when its less than the the PE threshold? Then once the TPS crosses that threshold what ever value is in that PE cell is what the new commanded afr is?

[trx2stroke4life39]

Can i get get away with a wide band with no gauge? I was looking at the plx wideband.

[S2H]

I have a question about that. Are you saying that the commanded afr is stoich when its less than the the PE threshold? Then once the TPS crosses that threshold what ever value is in that PE cell is what the new commanded afr is?

Basically yes..
there are a few other tables that can determine AFR...but for the most part once you cross the TPS threshold your PE kicks in at the EQ Ratio in your PE vs RPM tables...plus all the adder tables...
if PE is less than OLFA then OLFA commands the fueling...if PE is more than OLFA then PE commands the fueling..

all of them along with the ECT adder and IAT adder tables(and Boost tables on some OS's)

[S2H]

Can i get get away with a wide band with no gauge? I was looking at the plx wideband.

If you log the Wideband into your HPTuners MPVI thru the Aux Inputs then you wont need a gauge...you just Log the Wideband,Commanded AFR, and AFR error...then plot AFR error and copy paste special multiply by %-Half just like before
of course wen you use the wideband you need to turn off Fuel Trims completely while tuning

and I know you are looking at the PLX...but please do some research on here about the good and bad before you buy...lots of wideband which one threads on here

[98Camarod]

Basically yes..
there are a few other tables that can determine AFR...but for the most part once you cross the TPS threshold your PE kicks in at the EQ Ratio in your PE vs RPM tables...plus all the adder tables...
if PE is less than OLFA then OLFA commands the fueling...if PE is more than OLFA then PE commands the fueling..

all of them along with the ECT adder and IAT adder tables(and Boost tables on some OS's)

Open loop fuel adder is set to 1.00, fuel trims are disabled, boost tables are the same as PE, ECT adder are set to zero from 140F-230F, so all that is left is PE commanded afr and stoich right?

[S2H]

Open loop fuel adder is set to 1.00, fuel trims are disabled, so all that is left is PE commanded afr and stoich right?

not sure what you are asking there with the stoich?
stoich value has nothing to do with the actual fuel amount in our PCM's
it just changes the commanded AFR value based on EQ ratio..
most of our PCM's are EQ ratio based as I understand it...
which means its commanding 1.0 for stoich and *****************(got it backwards....see later post)

Edit:
EQ Ratio
less than 1=Lean
More than 1 = Rich

[98Camarod]

I follow you there, I'm just asking as far as the commanded afr since everything is basically negligible, the commanded afr is based off of stoich, 14.7, and the PE value when the TPS threshold is passed.

I'm just trying to figure out what the commanded afr is while at idle and part throttle transients that are less than the TPS threshold.

[S2H]

yes...

and non PE is always Stoich unless commanded to be something else
easiest thing is to log eq ratio...if it =1 then you are at stoich..

[98Camarod]

yes...

and non PE is always Stoich unless commanded to be something else
easiest thing is to log eq ratio...if it =1 then you are at stoich..

That makes sense, I didn't even think of logging it. Generally is the target for idle and part throttle an afr of 14.7?

[S2H]

Target is stoich for those situations
Which for gasoline is 14.68:1

[98Camarod]

Thanks! Being that it is a forced induction application doesn't have any bearing on those conditions since boost isn't seen in these areas right?

[S2H]

anything in boost will be more than 100kpa
100kpa is exactly 0 boost
101kpa is where boost begins

[98Camarod]

Cool, I have my Boost EQ to start at 100kpa, I'm not sure if that having 100kpa would be less than the TPS threshold. Either way it doesn't matter they are set to the same thing.

Thanks again!