To add my thoughts...
The MAP signal is used to calculate the load value for the engine (along
with the TPS, IAT, etc...) The load value is used to determine enrichment,
timing and the onset of Open loop. A high signal (low vacuum) is normally
associated with a higher load.
For WOT, If you can increase the onset of the load determination (or delay)
you will affect the onset RPM of the open loop mode. You are not in direct
control of the pulse width or the timing, the PCM is still doing that job,
but it will react differently if you, for example, place the zero voltage at
a normally lower voltage than expected once the computer zeros the
transducer. This will speed up open loop determination and enrich the
mixture as well as pull back the timing. If you increased the span on the
tranducer, you will delay the onset of open loop and effectively lean out
your mixture longer than "normal" increasing timing and response. Im not
sure what else you can do , but then again Im not an OBDII software
expert..Im not sure how much effect the MAP has on Open loop performance
once its in Open loop...
Bruce
----- Original Message -----
From: <bernd@texas.net>
To: <dakota-truck@buffnet.net>
Sent: Thursday, November 16, 2000 3:55 AM
Subject: DML: MAP Info
>
> For all of you who are sitting there scratching their heads on the whole
MAP
> Sensor thread (Viper Controller)...here's the basics on the MAP:
>
> "The Manifold Absolute Pressure (MAP) sensor reacts to absolute pressure
> in the intake manifold. It provides an input voltage to the
> Powertrain Control Module (PCM). As engine load changes, manifold
> pressure varies. The change in manifold pressure causes MAP sensor
> voltage to change. The change in MAP sensor voltage results in a
> different input voltage to the PCM (computer). The input voltage
> level supplies the PCM with information about ambient barometric
> pressure during engine start-up and engine load while the engine is
> running. The PCM uses this input along with inputs from other sensors
> to adjust air-fuel ratio."
>
> So, as for adjusting the Air/Fuel Ratio...here we go...
>
> - Bernd
>
>
>
>
>
>
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