Quote:
Originally Posted by Porsche
LOL! Fair enough, I'm game. But, can you EXPLAIN it to me please, Sir? Note the questions above.  |
The throttle plate in the airstream (intake manifold) is an analog device. It has physical open and closed stop positions.
It's attached to a rheostat (another analog device - Throttle Position Sensor - TPS) that transmits an analog voltage value depending on where the throttle plate is at any given time.
You can think of it as the Volume Knob (mine goes to 11). They're the same type of device.
The TPS voltage is subject to manufacturing quality variability. Each individual TPS will produce slightly different values.
The ECU is a strictly digital device that needs to combine readings from the TPS along with a bunch of other analog signals to tell how the whole system is performing.
Typically, from a cold boot (no electrons) the ECU is programmed to expect a safe range of values from the various other sensors.
If it sees something outside those values it throws codes and the binky out of the pram.
In the case of the TPS when in range, the ECU has to narrow down the actual analog voltages produced when open and closed.
Usually initial ECU values allow for higher and lower values that cannot actually be produced - the dead spots - that it learns to ignore if those values are never recieved.
Thus endeth the Digital/Analog for this evening.