>From what I understand on the PCM, it has static maps that are modified
according to the various sensor inputs. So, one could say, that indirectly,
the PCM is controlled by the sensors. Alter the sensors input/output and you
get different results. (Hehehe...proved that one by forgetting to hook up a
sensor...didn't run right.) ;)
"...the computer does not actually calculate the injector duration - instead it
looks it up in a table and then adds some correction factors. This method is
simpler and faster for the way the ECU thinks. There are two main factors the
ECU needs to know to find the base injector duration: engine load and RPM."
Man...my brain is starting to hurt again...but this is good learning and info.
$0.02
- Bernd
> 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>
> 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
> >
> >
> >
> >
> >
> >
>
>
This archive was generated by hypermail 2b29 : Fri Jun 20 2003 - 11:57:24 EDT