[Shotimes] BARO sensor

[Carl Prochilo]

Adam,  Let me impose further on your knowledge of the EEC IV program
for the SHO.  Since we've established that an incorrect signal will
not post a code in the diagnostics, if for some reason the BAP sensor
is in fact giving a lower voltage signal to the PCM that is correct
for the given environmental conditions, the car will not recieve
proper air/fuel mixture.  Is that correct?  Might a symptom of a bad
BAP be poor fuel mileage?
-- 
Cheers,
Carl Prochilo
92 Ultra Red Crimson

On Sun, September 18, 2005 13:45, Adam Parrott said:
>>> 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.  Eventally, Ford ditched
> both
> sensors altogether and looked to other sensor inputs to derive the
> needed
> atmospheric readings (as noted above).
>
> Adam
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