Thread: Sea Level vs Altitude Tuning
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Old Tue, May 5th, 2009, 09:12 PM
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DJ,

In order to not give away Bill's tuning expertise and secrets, I have "trimmed the fat" on this screenshot. This is the program in question vs. stock. Can you decipher WHY there is a dead pedal while the engine is cold all else being the same? The answer lies in these two maps.

Keep in mind that 40 degrees "C" is equal to about 100 degrees "F" and 100 degrees is a very cold engine and the actual additional pulse width above stock does not start to get multiplied until the engine temperature is above 22 degrees C (72 F). I don't know what the weather is like there but I haven't started the engine yet with the ambient temperature above 55 degrees and it takes a good while for the oil temperature (what the fueling is based on) to get to temperature.

Oh and as far as your data goes with APP percentage....what does the VOLTAGE say? The highest readable voltage that the PCM can compare to ground is about 4.75-4.8 volts. The software you are using may base 100% on a full 5 volts which is giving you the problem you are seeing.
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Tuning, PCM flashing, and burning chips for 7.3s since 2008. Repairing all aspects of 7.3L Powerstrokes for 25 years.
Eight 7.3L PSDs in the driveway including a 1994 Crown Vic and 1973 F100/2002 F350. Looking for the next victim.
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