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Old 12-06-2012, 01:30 PM
mbell666 mbell666 is offline
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Location: Austin, TX
 
Join Date: Jul 2012
Posts: 220
Mein Auto: e39 2002 540i6
The key thing is that the MAF (Mass Air Flow Sensor) reads the Mass of air entering the engine, so the signal it gives to the ECU already account of change in air density due to the altitude. The higher up you go the less air mass the MAF will signal to the ECU, so the less fuel the ECU will inject. The O2 sensors of course send fine tune to the ECU to adjust the air/fuel mixture which adjusts the short term fuel mixture adjustment, which over time adjusts the long term fuel adjusts.
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An e39 is like a beautiful wife, needs constant attention, lots of money, lets you down at the worse times but you’d never be without it.
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