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Re: Intake Air Sensor - important? Posted by Ari [Email]  (#2847) [Profile/Gallery]
(more from Ari) on Mon, 23 Oct 2006 07:32:03
In Reply to: Intake Air Sensor - important?, rob 94 cse, Thu, 19 Oct 2006 13:11:57 Members do not see ads below this line. - Help Keep This Site Online - Signup |
As yaofeng says, the IAS is used to calculate air mass. In older cars they used an Air Mass Meter, but in the Trionic cars, the engine control used the MAP (Manifold Absolute Pressure) and IAS to calculate intake air mass.
When the engine control sees an obviously wrong IAS signal, it goes to a default value. I'd have to check the Trionic manual for the default value, but I believe it's about 20 degrees C. It also lights up the CEL to let you know something is wrong.
As long as the mixture isn't too far off, the O2 sensors will keep the mixture OK in steady-state driving. Where it will be off is when accelerating. Depending on the outside air temp, you'll be running a little richer or leaner. Not a big impact on gas milage, as you (hopefully) don't spend that much time accelerating. But performance will be off, emissions will be up, and in weather cooler that the default you'll be running lean, which can contribute to knock and potentially burning a valve.
The Engine control is pretty amazing in that it can adapt to many sensor faults. But each sensor has a use, and there is some performance and/or durability hit associated. Again I'd have to check the Trionic manual - the CEL will go out if you fix the sensor, but it may not go out right away - you might have to disconnect the battery for an hour or so. But I'd get it fixed immediately.
posted by 192.249....
, Mon, 23 Oct 2006 07:32:03 <-- Viewing This Message, Tue, 24 Oct 2006 05:51:44
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