Proper air/fuel ratio is critical for performance.  A close coupled Mass Air Flow (MAF) sensor is intregral with the throttle body, and is used to measure the mass of air being ingested by the engine.  It is simular in design to the MAF on the 3800 engine, utilizing the principle of "hot wire anemometry."  This type of sensor is less susceptible to errors related to air temp, humidity, or altitude than the hot film type used on the 3.0L.

A heated wire is located in a bypass proportional air channel in the throttle body, and is heated to 75 degrees Centigrade (167 Degrees Farenheit) above inlet air temp.  The amount of
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Fuel Injector Assy
Fuel Rail Assy
Throttle Body Assy
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electrical current that is needed to keep the wire at 75 degrees C above inlet air temp is an indicator of the mass of air being ingested by the engine.  The total mass of intake air can then be calculated by proportion.

The MAF sends updated air flow information to the ECM at a min. of once every 500 microseconds, or 2000 times per second, and increases with air flow.  The information is used by the ECM in calculating the air/fuel ratio.

In addition, an oxygen sensor in the exhaust system is used to trim the ratio.  The ECM performs an updated air flow calculation, and adjusts the fuel delivery every 3.125 ms.  This means that regardless of ambient air temp, climatic conditions, altitude, or engine load, the air/fuel ratio delivered to the cylinders will always provide the optimum in combustion and fuel efficiency.

The Idle Air Control Valve (IAC) utilizes a 12mm dual slope pintle, as opposed to the 3.0's 10mm bypass channel and tapered pintle.  This pintle profile contributes to good cold starts, and enhances idle characteristics at low ambient temps.
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