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Old 12-19-2002, 10:02 PM
Arthur Dalton Arthur Dalton is offline
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Join Date: Aug 1999
Location: Florida / N.H.
Posts: 8,768
The HFM management unit is the ECU module that is used for both ignition and fuel management. [ N3/4- control module]
It is actually the HFM-SFI control unit. This is the unit he is referring to and it controls the ignition switching I mentioned along with fuel injector durations.
The MAS sensor is of the hot film design, [ changed from the earlier hot wire design, LH-SFI systems] and is one of the sensors that influences the HFM control unit , but is not referred to as the HFM unit, but simply the MAS ....
[ B2/5- mass air sensor] .

It is probable that the HFM-SFI unit is electrical faulty, but
the power feeds to and from the unit should be checked first...

Last edited by Arthur Dalton; 12-19-2002 at 11:23 PM.
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