programming for a MAF based system

Perry Harrington pedward at apsoft.com
Sat Apr 6 07:25:46 GMT 2002


On Wed, Mar 27, 2002 at 03:49:05AM -0500, Justin Becker wrote:
> It is my understanding that the Ford EEC-IV mass-air engine control system
> references the BAP (ambiant manifold pressure) only at start-up, before the
> engine cranks. I beleive it is to determine air density (altitude in a way)

That is correct.  I find it to be a stupid design, but nonetheless...

> to minimize emissions, and make the car run better in every situation. Is
> this true? Is there a way for the BAP to be referenced more often in the

It's integral to the air density calulations.  Air temperature and altitude
are additive, meaning that once you get the MAF signal, you have to process
it with the baro data to obtain a true mass calculation.

> case of adding positive manifold pressure (super/turbocharging)? How did the

No, not unless someone has reprogrammed the algorithms in the EEC.

> Supercoupes reference boost (manifold pressure) in order to supplement
> control of the air/fuel ratio as well as timing; if they did at all? Anyone
> have any clues?

The Tbird SC did not have a MAP sensor.  The boost was proportional to RPM and
Ford just did all the work on a dyno.

They did however have Octane adjust and knock sensors to compensate for too
much timing.  They did anti-knock on a per cylinder basis and adjusted their
timing based on the fuel octane.

> Also, what is ISV?

Idle stabilizer valve.  Otherwise known as IAC (Idle air control) and IAB (Idle
air bypass).

ISV is the more boschish/digifant nomenclature.

> Justin
> 

--Perry

-- 
Perry Harrington             Linux rules all OSes.               APSoft      ()
perry at apsoft dot com 			                 Think Blue. /\

Those who would give up essential liberty to purchase a little temporary safety
deserve neither liberty or safety. Nor, are they likely to end up with either.
                             -- Benjamin Franklin

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