I'm used to the ls world and not familiar with the mustang tuning, despite my searching i can't seem to find an answer to my following question, so im hoping some of the gurus here can help out
With an ls1 you can use a resistor in place of the intake air temp sensor (called air current temp on 5.0's) and it will lie to the computer telling it that the air is around 53 degrees, which makes the computer pull about 2-3 degrees of timing.
has anyone done this on a 5.0 stang?
Why? If you want to retard timing, just set the base timing back 2-3 degrees. Or do you want to pull timing at higher loads and not at idle?
Why would an EEC from the late 80's Mustangs be like the PCM in an LS1? The Mustang doesn't pull timing when air is cold. It pulls it when air is too hot.
More importantly, can someone tell me what the computer uses to determine the temp, does it reference the volts from the sensor or something else?
It measures an ACT sensor's resistance via a fixed voltage reference though a pseudo constant voltage source with fixed ESR. As sensor resistance changes with temperature, the voltage at the EEC ACT terminal changes. 5v is the nominal open circuit voltage with infinite sensor resistance. It is a NTC element, temp up=resistance down.
Also, what is the reference signal the computer gives to the sensor, i think it gives it a 5v reference but i don't know at what amperage.
It is a simple voltage division circuit that follows Ohm's law. The current is not constant, it varies with sensor resistance and is in the micro-amperes and milliamperes, depending on temperature. For example, at 50k resistance it would be roughly about 100 uA.
I'd try to track it down using a multimeter but i'm at school for the semester and am away from the car, so, to stay interested, im doing some research for when i can get back to the car
Why would you want to screw up the ACT reading? It doesn't do much (within reason), but could cause some problems with cold starting performance economy.
Why would someone want to disable the sensor?