Re: BPW and Cylinder Vol.?

[rrauscher@nni.com]

The prop gains are what keeps the O2 swinging rich/lean. They
work in the opposite direction of the O2 sensor value. Typically
the prop term is summed with the INT term before being
summed into the bpw term.

If the prop gains are too high, the int keeps chasing it's
tail. This can also occur when the ve tables are still rough
and the fueling doesn't follow the real ve well enough.

In short, the prop term becomes another variable that
can keep you guessing. . .

BobR.

>For your mention on getting better results on lowering/correcting the IC but

>still having some other issues, also look to lower the minimum base pulse
>width so your program can lower the fueling at low loads such as idle and
>decel.  Also, msec BPW threshold to learn in all cells as this will of
>changed with larger injectors too.  also msec threshold between cell 1 and

>cell 2, msec bpw threshold determines cell 1, msec min and max async pulse.

>Bob mentioned lower the prop (proportional?) gains before going back to
>closed loop operation and final tuning and I am wondering the prop gain of?

>
>Jeff M
>
>
>> In my case i'm starting from scratch, 468cid, single-plane port fi, cam,

>heads, headers, etc.  I
>> just discovered last night that lowering the injector constant has leaned

>me out enough that I can
>> start doing some real VE tuning.  It's doing some weird things, tho.
>>
>> How would u force open-loop all the time?  I suppose locking the BLM at
>128 would help.
>>
>> Squash
>>
>> --- rr <RRauscher@nni.com> wrote:
>> >
>> > I'd put the proper values at those two location according to what is
>> > really in the engine for displacement and injectors. Then use the VE
>> > tables to correct the afr. If you have changed the cam, the exhaust,
>> > or the intake, the ve has changed.
>> >
>> > For some reason, I think the cyl vol is used in the egr calcs.  ECM
>> > needs to know gms/sec of airflow for egr lookups.
>> >
>> > You can rough in the VE tables by tuning in forced open loop, then
>> > fine tune them with closed loop. Don't forget to reduce the prop
>> > gains before the closed loop tuning.
>> >
>> > BobR.
>> >
>> > I've been thinking that a spin machine would be nice to get the VE
>> > measured close enough. . .
>> >
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