Fords MAF
DIRK BROER
OADDAB at STDVAX.GSFC.NASA.GOV
Mon Aug 22 20:05:38 GMT 1994
>> >What metod do the latest ford MAFs use to measure MAF. Flapper valve,
>> >hot wire (doubt it) or?
>>
>> They are all hot wire, and because of the sampling method don't require
>> the old-style burn off.
>>
>
>Can anyone elaborate on burn off and the sampling methods employed?
Ford MAF sensors differ from the standard Bosch sensors. The Bosch Sensors
typically have a large screen infront of the wire and a wire that crosses
the full width of the MAF sensor. So if you have a 70mm MAF the hot wire
is 70MM long. The ford sensor uses a small venturi placed in the air-
stream (I think to one side) since it is much smaller - it doesn't get as
dirty and therefor doesn't need the burn-off (at least according to the
Probst book). The problem comes when the sensor gets modified - any change
in the air-flow characteristics can/will change the signal vs. air flow
characteristics. Someone on the net mentioned that porting the Ford
Sensors was a neat way to lean out the WOT fuel mixture - from what I have
seen WOT on the Mustang can be as much as 11:1 A/F ratio - plenty safe but
not necessarily optimum power.
Also it seems the aftermarket MAF sensors are geared to a specific injector
size. So on a mustang you can buy 77MM MAF - tuned for both 19lbs and
24lbs injectors.
Dirk
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