ECU file format bug or gray matter loss? [was Re: Idle Block Learn Cell ??]

[Michael Davis]

I don't know if this has been hashed out before, but I can't see, to
rationallize the conversion limits of the .ecu file format for an
equation of the form:

	eprom-value = constant / converted-value

It appears to me that the .ecu files are setup to either multiply or
divide the eprom-value by a constant, but don't have provisions for
doing the 1/x inversion as needed above..  Am I missing something?

I found this bit me in the A$$ twice now with the 7730v3.ecu file 
with both the AFR and the base injector (g/s) settings..
(I've been tweaking down VE tables for 3 months trying to lean out the
 motor and just found that my first setting of 24lb/hr injectors was
 actually in the eprom as 18lb/hr because of the conversion...)

(I was using WinBin, but don't believe it to be the problem...)

mike

In message <20000613143134.9794.qmail at web121.yahoomail.com>,Squash writes:
>I figured it out yesterday...  The original idle speed for an aujp is 600, min
>e is now set to 800
>rpm.  I made the mistake of having a chip done by a S&P, and now i'm fixing al
>l the stuff they did
>wrong (like they didn't change the VE table or idle BLM cell, etc).
>
>There is a bit in the anht_hac that says something about disabling "CCP" at id
>le, is CCP a learn
>mode?  
>
>My setup has run 10 out of 16 cells, but i'm sure i can get into the rest if I
> try...
>
>Now my problem is the BPW.  I switched the idle cell to 13 (the correct one fo
>r 800rpm/50kpa) and
>now I can actually tune it.  But it appears that I can't take enough fuel out,
> so I dropped the
>BPW to 5.008 from 6.7 (location 41A).  That had the desired effect, (leaning i
>t out), albeit a bit
>too much.  But the commanded AFR now reads 19.9:1.  I think maybe I should cha
>nge the injector
>flow (41C) instead, but i don't quite understand what effect that will have.  
>I'm scanning the
>archive files now.
>
>Any ideas?  I've found the spots in my VE maps that need to have the least fue
>l and I need to
>bring it all down a notch.
>
>Thanks,
>Squash
>
>--- rr <RRauscher at nni.com> wrote:
>> 
>> (With the pulling of fuel not affecting your idle, double check that
>> you are changing the right area. All it takes is setting up the .ecu
>> file incorrectly, been-there, done-that).
>> 
>> As for the blm idle cell=4, it is sometimes difficult to understand why
>> gm does things. If I had to guess, it would have to do with drivability.
>> Maybe to prevent a drastic change in an area that is then used when
>> 'coming' off idle. Maybe to prevent a rough idle from switching between
>> two cells. On the '747, certain conditions will prevent an int reset to
>> 128 when the cell selection changes. Like whether the O2 is sensing a
>> rich condition, or the ecm is in decel enleanment.
>> 
>> How many other cells have you seen in use? Are all sixteen used, or
>> just a couple? AZTY 730 v6 bin only uses three cells, idle, cruise and
>> a decel cell. That's all I've ever seen used. Other bins use two cells,
>> throttle open, and throttle not open.
>> 
>> hth's
>> 
>> BobR.
>> 
>> Squash wrote:
>> 
>> > While doing some tuning this weekend, I decided to work on the idle.  It's
> been running
>> > 51kpa/800rpm with 4/108/100 cell/blm/int.  I went into the lower VE table 
>(aujp) and around
>> > 800rpm/51kpa I pulled fuel out, which had no effect on my idle!  So I chec
>ked around the ANHT
>> hac
>> > and there is a setting for which cell to use at idle.  It was set to 4, an
>d I had assumed
>> > something else, so I was wrong there.  But 4 is *not* where 800/51 is loca
>ted.
>> >
>> > Why would I want to use cell 4 for idle?
>> >
>> > Squash
>> >
>> > =====
>> > Trains, Trucks, and EFI at http://www.trailrunners4x4.org/users/realsquash
>> >
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>
>
>=====
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>
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