MAF diagnosis

[Q45tech]

IS DIFFICULT!Unless it is the simple corroded connection type!

You must mentally know what the correct voltage reading is for the exact operating condition of the engine.As the ecu has an internal graph of average volmetric efficiency for rpm vs TPS voltage at 60F and 29.92 HG and zero humidity.You must be able to correct for temperature [1% per 11F] and barometric pressure and altitude and humidity.

Summer heat is the most difficult as 120F [air into MAF] 120-60=60/11=5.5% lower density same with sea level vs higher elevations. HOT SOAK could allow 170F air to pass for a 10% reduction]

Things should be within 10% of the internal normal numbers but they allow 20% errors before throwing codes......[why you almost never see a MAF code if the unit is kinda working].http://www.allfordmustangs.com...s.xlshttp://www.allfordmustangs.com/Detailed/583.shtml

The following charts are the closes one I could find [probably within 5% accuracy] for what you might expect with the 90-95 Q MAF!

http://www.pro-flow.com/flow%20sheets/c ... /cob24.htm

The Q uses 35 lb/ [370 cc] injectors but they limit the open time to 60% but Ford uses 77% limit so we need a chart between the above two. Something like a 27.

4.4 volts ~~ 270 HP on the 24 chart and 336 HP on the 30 chart, nether is correct for the Q splitting the difference indicates 303 HP probably right on correct. As I can get a 4.42 on cold ocassions.

Having enough air for a certain HP level doesn't mean the engine can produce it [A/F ratio, ignition advance, BMEP ring condition and parasitic load from auxillaries, etc etc.]

Other charts:http://www.pro-flow.com/flow%20sheets/37ptflow.htm

http://www.jimwolftechnology.c...S.PDF

[Q45tech]

Move to same 93 Q chain guide discussion