VandykeT/A

I'm new to hptuners so I bought dan maslics book. And it says when tuning fueling change the ol eq ratio to command a 12.5 afr but then to adjust pe table as well. I just don't understand the purpose of commanding the 12.5 in the ol eq if the pe table is the primary table for wot fueling. And once the pe is tuned do I set the ol eq back to stock? And for instance I want it leaner than 12.5 do I need to change the ol eq and the pe table?

LSX Power Tuning

iTrader: (4)

The pcm will use the richer of the two if they dont match.

RedWS6 00

A stock tune tends to be on the richer side of things. You can command 13.1 AFR at peak HP, keep around 12.5 AFR at peak TQ. The 13.1AFR is a bit leaner and you can get more power. I wouldn't do this though unless you have a Wideband rigged up so you make sure you don't go too lean. I would change this in the PE table. During tuning log the Wideband readings and make and then adjust VE table with a +/- adjustment.

jimmyblue

iTrader: (11)

I view the main EQ table as being the generally relevant
one (fueling should follow cylinder charge, which follows
MAP until airflow begins to fade) and PE as the "patch"
for RPM based issues like fuel fade and airflow fade -
sort of a foot-race, there, as RPM goes up. If you want
a smart enrichment that only pushes as much fuel in
the mid-MAP ranges as necessary, a tailored EQ table
is the only way to get that and a PE table that asserts
full-throttle enrichment at below-full-throttle positions
will put you full rich unnecessarily (mid-throttle economy
and performance / drivability both suffer).

But getting this trued up would present a lot of work,
and if you have "digital foot" then maybe PE mode and
forget the EQ table gets you to half-***-done quicker.
Just be aware of what you're leaving unfinished.

sum guy

iTrader: (4)

I think in the book he means to temporally set the command to 12.5 in all cells and force into open loop then when you data log/ histogram you can see exactly how much the commanded afr and actual are apart. Adjust maf table till they match then reset eq and 02 back to factory so the PCM can take back over the afr with the now accurate maf table. Make sense? I'm about to tune my truck maf to a camaro so I'm trying to make sense of it too.

joecar

The OL EQR table is active only in OL...

(...and as said the PCM selects the richest current operating cell from the active tables...);

if you're in CL and go WOT (or do something to enable PE), the PCM retains a CL "mode" (where it adds only the last CL positive LTFT's), it does not go to OL, so the OL EQR table is not active (so fueling comes from the PE table)...

soundengineer

iTrader: (16)

I'm sorry... you are wrong...

when you go into PE, it is open loop...
if your OLFA table is Richer than your PE table, it will use the OLFA table
if your PE table is Richer than your OLFA table it will use the PE table

it always defaults to the Richest value in open loop
and it doesnt matter if it was just in closed loop and you go WOT....

PE is open loop


PE will retain a certain level of positive fuel trims(it does not retain negative fuel trims).....and they will be added to the PE commanded value

joecar

Nope.

joecar

See this set of experiments we did: PE-Mode-Controls-All-Closed-Loop-Fueling

( in EFILive, B3618 = PE EQR table, B3605 = OLFA EQR table )

we did 6 tests (in the order shown at that link)(using EQR fueling units):
1. CLMAF with PE at 1.00 and OLFA at 1.13 --> result was commanded fueling was 1.00
2. CLSD with PE at 1.00 and OLFA at 1.13 --> result was commanded fueling was 1.00
3. OLMAF with PE at 1.00 and OLFA at 1.13 --> result was commanded fueling was 1.13
4. OLSD with PE at 1.16 and OLFA at 1.13 --> result was commanded fueling was 1.16
5. OLMAF with PE at 1.00 and OLFA at 1.13 --> result was commanded fueling was 1.13
6. OLMAF with PE at 1.16 and OLFA at 1.13 --> result was commanded fueling was 1.16

( and same results have been found with other earlier OS's )

The above results can be summarized as:
- OL: richest of PE and OLFA prevails.
- CL: PE prevails.
(edit: typo fixed)

If you log the FUELSYS A/B pid, you will see that when you go from CL to WOT, the mode is not "OL" but something else...
( and the LTFT are not being updated, but any last positive LTFT are added (i.e. negative trims are rounded up to zero) )
so the mode is not OL and so the OLFA table is not active, so the only active table is the PE table;
so the above can be summarized as:
- the richest of the active fueling tables prevails.

we also did experiments that mixed in the other fueling modes (PPM, EPM, COTP) and again we can summarize as follows:
- the richest of the active fueling tables prevails.

Sarg

iTrader: (6)

At what conditions does PE enable when in closed loop? I thought (maybe incorrectly) that it only enabled when you crossed a certain threshold and went open loop.

joecar

Tests 1 and 2 are going from CL to WOT (see pics in link above):
If it went OL then it would have selected OLFA (1.13) over PE (1.00).

Sarg

iTrader: (6)

I did see that, but in what conditions is it using this? Is it just when you first stab it to go WOT? Just trying to wrap my head around this and also wondering if I have not seen this behavior before in my car.

joecar

Throttle is held steady state wide open...

[ pics of graphs show several manual trans upshifts (test 1 shows 3 upshifts, test 2 shows 1 upshift) ]

PE enable conditions were:
- MAP threshold 65 kPa
- TPS threshold is 65% below 3000 rpm, 35% above;

( you can manipulate those to enable PE at say 30 kPa and 5% TP, set PE to 1.05, and watch what happens before/after entering CL )

jimmyblue

iTrader: (11)

Is this "CL mode" of open loop PE tied to positive LTFTs
being present? Or regardless of that? What is it that makes
the truism of fattest-wins, not so (what makes the tables
active or not)?

I think in some of the collateral material I saw that this
is data from a custom OS from EFILive. Is there any
difference in this respect between the COS and stock OS?

2xLS1

iTrader: (25)

Would be pretty easy to just test it yourself on whatever platform and OS you have rather than relying on something read on the internet.

joecar

I think the "positive" LTFT's being added are a consequence of this modified "CL mode" (negative LTFT are first rounded up to zero, so LTFT are "positive").

Lol, internet has always said that PE is OL... but when you observe a few pids and do a few experiments you find that it is not necessarily OL... going from CL to WOT (and PE enables), you see what seems to be a modified form of CL (for lack of a better description, because it is not CL in its usual form).

What makes it not so: IDK; but as you saw, in CLMAF, when PE was leaner than OLFA, PE prevailed... why? IDK... but it might mean that the OLFA table is not "active"... this and the positive trims being added makes me conclude that the fueling mode is not OL.

OS is 12212156 (stock OEM OS) (i.e. 2002 Camaro/Firebird/Corvette), not a COS.
( you possibly saw the test "richest table wins" done in OL using COS5, but the test has since been repeated using various OEM OS's )

( COS differences: the COS remaps OLFA from ECT-vs-MAP to RPM-vs-MAP... but a COS was not used here )

(lol) I've stuck out my neck (with all respect)... so I simply invite you (all) to look at this from a new perspective (mental model) and see if it fits your data... if it is correct and if it simplifies tuning (by simplifying/unifying the fueling rules) then we made progress.



edit: clarified

joecar

+1 x2

2xLS1

iTrader: (25)

And joecar, I was not trying to discredit your observations, just stating that different platforms and OSs may respond different and people should test it them selves to see whatever they are tuning on does.

joecar

I'm ok with your post, no worries

I would love to see people's tests on whatever they are running.

joecar

It modifies the truism from "fattest wins" to "fattest of active tables wins".