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Old 04-14-2005, 03:22 PM   #13
bboy
Scooby Specialist
 
Member#: 56468
Join Date: Mar 2004
Chapter/Region: NWIC
Location: Seattle, WA
Vehicle:
04 Improved STI
Dirty White

Default

Quote:
Originally Posted by subieworx
Did Phil ever figure out why your car wouldn't start? Was it user error? What about the lack of throttle response?
It has to do with the voltage range of the TPS, remember STI is drive by wire. The TPS sensor is down by the pedal. On some STI's the voltage at 0% TPS was higher than on other cars. The computer will only accept so high a voltage as the 0% TPS value.

Think about it this way. On my car let's say 0% TPS = 0.02 volts and 10% TPS = 0.1 volts. On offsets car 0% TPS = 0.1 volts and 10% TPS = 0.2 volts. Can you see that a higher than "normal" voltage coming off of the TPS sensor could be dangerous. If you put offset unit in my car without TPS callibration the throttle would be open at 10% without every touching the pedal.

We do calibrate the TPS during the install process so this scenario does not happen, but as a safeguard the Hydra will only accept a certain maximum 0% TPS setting. If you are old enough you will remember the problems with some of the first DBW cars like the Audi's that would drive through the back of a garage "thinking" the pedal was at 0% TPS, but delivering 10% (whatever) signal to the throttle electronically.

offset's car started, but would not respond to throttle input (i.e. touch the gas pedal, no more revs--throttle opening).
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