The LH -SFI and HFM-SFI systems are both Full Electronic measure of air mass without any mechanical to electric sensing ..
[ mechanical vane or flap mechanically hooked to a pot resistor ]
These are called MAF [ mass air flow ] sensors.
They work by maintaining a temperature through a weatstone bridge circuit and the reguired voltage to maintain this temp
is analized by the computer .. kind of it's own little closed loop maintaining system,,-- so, no Mechanics of any kind ... and a better sensor, as it considers air density/temp now..
LH uses a Hot Wire to do this, and the later uses a Hot Film .. otherwise , they are about the same ..
The new technology on air measure is AMMs that use a frequency base signal, rather than linear voltage,,
I think we will see these in every car in the near future, along with Wide Band 02 sensors
...they just get better and better ,,,
Using MAS for MAF , or AMM can be confusing , but when in context, I think we know what is referred...
Last edited by Arthur Dalton; 06-15-2003 at 07:58 PM.