RE: RE: Quick D

From: Bernd D. Ratsch (bernd@texas.net)
Date: Sat Sep 11 1999 - 18:00:55 EDT


Hey Pat,

Here's the technical description:

The Manifold Absolute Pressure (MAP) sensor measures the changes in the
intake manifold pressure which result from engine load (intake manifold
vacuum) and rpm changes; and converts these into a voltage output. By
monitoring the sensor output voltage, the ECM know the manifold pressure. At
lower pressure output voltage will be about 1 to 2 volts at idle. While at
higher pressure or at Wide Open Throttle (WOT) output voltage will be about
4 to 4.8 (Readings may vary from one manufacturer to the other).

The MAP sensor is also used, under certain conditions, to measure barometric
pressure, allowing the ECM to make adjustments for different altitudes. The
ECM uses the MAP sensor to control fuel delivery and ignition timing.

There are also three different types:

A 1 bar sensor would be used on a naturally aspirated engine. 2 and 3 bar
sensors are used on a turbo or supercharged engines.

- Bernd

-----Original Message-----

I thought the MAP was a pressure transducer.
Dr. Pat

----------
<snip>
 The MAP is a speed density setup. When you open up the
> bores, the MAP sees a lower velocity.
<snip>
> Frank
>



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