[Shotimes] BARO sensor

[Kevin & Cheryl Airth]

Adam:
 Thanks for the in-depth review and answer!! Learn something new everyday in
SHO Land!
.
.



> >> So the DPFE does NOT tell the PCM what the BP/MAP is? But BP is
calculated
> or inferred from the other sensors? I had it in my head that somehow the
DPFE
> fed a BP/MAP reading to the PCM. <<
>
> For some reason, I used to be of the same thought (that the EEC inferred
BAP
> readings from the DPFE sensor or EGR system on the Gen 2 ATX cars).  It
wasn't
> until I consulted my EEC strategy documentation that I discovered that, on
> non-BAP-equipped cars, the EEC infers it's BARO readings from other sensor
> inputs (usually the MAF, ACT and TPS).
>
> >> Now this makes me ask: If the BP can be inferred from other sensors,
why
> would a cheapskate like Ford spend the money to install a separate BP
sensor?
> <<
>
> While there several theories floating around out there, I personally
believe
> the answer has to do with the fact that, at the time, the Ford engineers
> relied upon these additional sensor inputs to supplement their
relatively-new
> mass air flow technology.  As time went on, the engineers were able to
refine
> the inferred strategy to the point where the MAP/BAP sensors were no
longer
> needed, resulting in a significant cost savings.
>
> >> Also the SHO does NOT have a MAP sensor (and this is required) so the
> inferred method seems to be missing something for our SHO's? The equation
> below does not use a MAP input so maybe the MAP is not needed as an input
at
> all? <<
>
> In studying several of the various EEC strategies, I have found that the
> actual logic and sensor inputs used to infer barometric readings will vary
> depending on the calibration or strategy in question.  Some early setups
(like
> some '89-'95 Mustangs) required both sensors, while others (like the
'89-'95
> MTX SHO) relied solely upon a BAP sensor.  Eventually, Ford ditched both
> sensors altogether and looked to other sensor inputs to derive the needed
> atmospheric readings (as noted above).
>
> Adam