VE table tuning philosophy - need help

[blucreek]

I've learned that in order to get the MAF or VE tables AFR error closest to 0. Once I've choked the error to +/- 1 use multiply by 1/2% Seems to keep the error closer to 0, for me anyway



chris

[viperbluelx]

why would anyone tuning with a wideband set the OLFA table to all 1.0's???

[Cantalope Kid]

why would anyone tuning with a wideband set the OLFA table to all 1.0's???

Maybe Bill@HpTuners can explain this...it did make it into their help menu as a user submitted walk thru. No wonder I'm always buggin' WS6FirebirdTA00 about his personal tuning guide! When is an understatement. Lol

Not really, the information is every where as it is. The problem is sifting through the bullshit

Ditto. Couldn't have said it better myself. The real problem is as a noob not knowing what is bullshit and what is FACT.

[Dan_the_C5_Man]

I want to sincerely thank all of you for your responses - you clarified several points for me, huge help.

I may have one or two follow-ups, but I believe you've put me on the right track. Thank you!

[Frost]

why would anyone tuning with a wideband set the OLFA table to all 1.0's???

so that commanded AFR is always stoich when warm. You can leave it stock, but commanded fueling moves around adding a lot of transitional error that can be minimized if always commanding a single value.

[JimMueller]

CFCO = Clutch Fuel cut off? I don't see it in my '98 calibration. Which models have it?

[Frost]

It's under DFCO's tab... something like enable clutch transition...

[JimMueller]

OK, I don't have it then...thanks.

[12secSS]

You have essencially 3 different WOT range fueling modifiers that have direct affect on your AFR at all times: PE Enrichment table, VE table (at the 95, 100, 105 kpa ranges) and OFLA table (at the same ranges as the VE table). More on that but first- You will also know ur in PE if your TPS% and MAP satisfies the PE Enabled table, alas you will be in cell 22/OL. At any rate, you can certainly tune your WOT/PE parameters utilizing the VE table, the numbers >95kpa MAP + your WOT RPM range you wish to tune will affect your AFR per your WB. I dont try to Paste Special the %err from the histogram scans to tune WOT PE AFR, I simply look at my WB scan recording results in the cells 95, 100, 105 (or more if you have 1 bar HPT + forced air) kpa readings throughout the RPM range I am tuning for my 12.8:1- 13.0:1 AFR for naturally aspirated WOT AFR. I make changes in those cells accordingly in my VE table in those cells. Leave the OLFA cells at 1.001 in all the wot range as well as your PE Enrichment table to 1.001 then simply tune your WOT AFR using the 95,100 and 105 kpa cells in the VE table. Using the VE table to tune your WOT along with Closed Loop part throttle SD tuning gives you a little more resolution to tune WOT AFR because instead of a single cell per RPM column to tune WOT (as you only get in the PE Enrichment table) you get 2-3 cells per RPM column to tune naturally apsirated WOT in the VE (95kpa, 100kpa, 105kpa cells per each RPM column). Remember to leave your OFLA at 1.001 in the WOT range and leave the PE Enrichment table alone, as well, at 1.001 as these are WOT modifiers at all times.

Wow, this is not the way to do it. The OLFA and PE tables are Commanding Fuel Air tables, which means they dictate what the AFR should be. The VE table (and MAF, if used) let's the computer know how much air is entering the engine based on the axis sensors (VE: MAP x RPM, MAF: Hz), so that the ECM can calculate the correct pulse width to meet the OLFA and/or PE required AFR.

That other method is doable, but would require a lot of work to fine tune the AFR at given points of the power curve.

The quoted post above is one of the BS post to avoid, if you are a beginner and learning to tune.

[EaglePerformance]

and leave the PE Enrichment table alone, as well, at 1.001 as these are WOT modifiers at all times.

I just re-read this, don't know how I missed it, but leaving the PE table @ 1.001 sounds a bit dangerous, makes it a bit tough on the engine while tuning WOT.

[Duffster]

I thought the PE to 1.00 was for VE tuning and not WOT...

[Cantalope Kid]

No folks...PE is never set to 1.0. The OLFA (Open Loop Fuel Adjustement) is set to 1.0 when tuning VE. The OLFA is used when you vehicle warming up to temp. and normally from the factory is set to a rich value as you vehicle warms up. You set OLFA to 1.0 across the board to command a target value. i.e. Value in OLFA = 1.0 / Stoich AFR 14.63 AFR. When you go WOT PE takes over which is then set to whatever you tell it...i.e. PE = Stoich AFR 14.63/ Value in EQ table 1.167= 12.5 AFR.

[Gh0st]

IIRC and I may be wrong...

If your OLFA is richer than your PE commanded your computer will use the OLFA commanded fueling instead.

Like I said, I may be wrong, not sure if that's true anymore.

[redhardsupra]

there is no need for setting OLFA to anything weird for tuning. OLFA's effect will show up in AFR commanded, thus in AFR%error.

[Cantalope Kid]

IIRC and I may be wrong...

If your OLFA is richer than your PE commanded your computer will use the OLFA commanded fueling instead.

Like I said, I may be wrong, not sure if that's true anymore.

Correct. Was this a general statement or in refrence to a post above?

[Cantalope Kid]

there is no need for setting OLFA to anything weird for tuning. OLFA's effect will show up in AFR commanded, thus in AFR%error.

True BUT if you leave in the stock values you will be shooting for an AFR value during warm up and regular driving (Your in forced open loop at this point) that is all over the place as engine temp. rises. Easier to hit a single target like OLFA = 1.0 = 14.63 stoich to tune your VE table in OL using a wideband.

[redhardsupra]

no, it's not easier to hit a single target if you understand the math behind AFR%Error. first of all, AFR shouldn't be a single target. secondly, you need these non-stoich values for cold engine operation. thirdly, you shouldn't be tuning on a cold engine.

[Gh0st]

no, it's not easier to hit a single target if you understand the math behind AFR%Error. first of all, AFR shouldn't be a single target. secondly, you need these non-stoich values for cold engine operation. thirdly, you shouldn't be tuning on a cold engine.

this

[jdeatsch]

So us newbies just need to throw the CPIG deal in the circular file?

Hmmmmmmmmm?


Jim

[Cantalope Kid]

no, it's not easier to hit a single target if you understand the math behind AFR%Error. first of all, AFR shouldn't be a single target. secondly, you need these non-stoich values for cold engine operation. thirdly, you shouldn't be tuning on a cold engine.

Just trying to learn. Please explain your reasoning? I understand AFR%Error to be nothing more than the difference between what I am commanding vs. actual AFR. Are you saying its easier to hit a constantly moving target AFR?

Realize hitting a single target AFR value when not in PE is ONLY used for VE tuning in OLSD. You still set everything BACK once complete. At this point you can either choose to stay OLSD or go tune your MAF to continue running hybrid (ve/maf) as from the factory. OR of coarse if your going to run MAF only you could do so but why waste time on VE tuning then...Lol