LS1 Lean Cruise

[Bruce Plecan]

By Federal law it was supposed to be availble public domain, in 81,
needless to say lawyers will get their 20 years retirements on tieing this
up in court.
Bruce

> Ah, the 'ole EPA. By making it a separate function,
> it is kept out of the IM240 loop. Clever. Makes
> sense now.
> BobR.
> Gee, be nice to have source, wouldn't it? Anybody
> here work for the EPA? <g>

> >I'd suspect two things:
> >It was again a patch job, someone had an idea way late in th program, or
one
> >area had no clue about what someone else was doing.
> >Or, it was lets try this, and see if we can get away with it.  Figuring
if
> >one area didn't get approved then another might.
> >gotta remember the EPA had the source code, and could look up anything
they
> >wanted.
> >Bruce
> >> I haven't quite figured out why gm kept them separate. When in
> >> light cruise, closed loop, it is easy to use the main SA table
> >> to give the SA required.
> >> When going into a lean fuel mode, additional timing will help.
> >> It stabilizes the burn, along with bringing some power back.
> >> Only need a couple of degrees (2-3). On my daily driver, I
> >> ended up tying the hiway SA and fuel together. Secondary info
> >> from the NACA site Dave posted supports this. I also had some
> >> roughness when at 16.1 until I added a couple of degrees of SA.
> >> Then like you mentioned Mark, the hiway afr & sa change with
> >> the map load.
> >> BobR.
> >> >There are two things going on here.
> >> >1) Hwy Fuel
> >> >2) Hwy Spark
> >> >Two separate things.
> >> >Hwy fuel is a light load commanded, calculated afr setting.
> >> >Kind of like pe, it checks back to 14.7 to one to make sure the
> >> >BL and INT are ok.
> >> >Hwy spark is a light load commanded spark adder.
> >> >The hwy spark is just load and rpm dependant.
> >> >The hwy fuel is speed, load, coolant temp and rpm dependant.
> >> >(My experience is ONLY on the 89 Vet code.
> >> >86-87 code has only hwy spark (As far as I have been able to
determine)
> >> >Mark


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