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Old 03-27-2013, 07:45 PM   #13
6SPD_soul
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Join Date: Feb 2008
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The MAF actually uses a 5ish volt feed to a resistor thats placed in the intake stream of air, as increasing volumes of air flow past the MAF resistor, the cooling effect of the airflow decreases the MAFs resistance line, and the PCM receives a corresponding increased voltage (since it's being cooled by airflow) return and thus more air volume is measured going into the engine.

Cold air didn't cause any problems here, not by itself. If you could magically feed your engine -50F air while ambient temp for fuel and everything else was a more reasonable 35F, it would probably be a very happy engine and car. There would be a point eventually when the fuel trim would be pegged out maximum rich and no longer be able to supply any more extra fuel to match the actual volume of the super dense cold air ingested, and then the engine would just run leaner than the 14.7:1 it was shooting for. It would still run, and probably into -100F given the fuel and the rest of the car were at a magically balmy 35F, it would be dangerously lean and could cause damage, but it would probably still run. If I had to guess, this might happen at maybe -70F, again assuming the rest of the car and fuel were in a magical 35F environment. Even if it weren't a magical 35F everywhere else, who knows when the fuel would start to gel or freeze or stop proper atomization. Probably at colder temps than anyone could expect to reliably survive in.

Were there other cars on the road when yours stumbled? Was your car getting air any colder than the cars around you? Possibly, but it still wasn't any colder than ambient temp and they were probably getting around fine still. Every model of car on this site went through cold weather testing probably between -30 or -40, they may have even tweaked the antifreeze to enable this.

Please don't "bash" peoples valid responses until you fully understand them.

Last edited by 6SPD_soul; 03-27-2013 at 10:18 PM. Reason: I wasn't mean enough yet.
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