The TPI reads throttle percentage against engine load requirements, this reading is sent to the ECU and it is only part of the information required to set injection timing, spray duration, ignition settings, id the TPI is out of calibration or sending conflicting information if relationship to other readings at the input of the ECU, it will determine that this is a fault and the code will be set, the temp sender will be an earth resistance sender, that is the sender when heated by the coolant will alter resistance and send a varying signal to the gauge, the hotter it gets the less resistance there is so the gauge deflects further(goes from cold to hot) earthing the wire with the ignition on gives a zero resistance so the gauge will deflect to hot straight away, the tank sender works in a similar way but not on heat, it uses a float and a wiper arm mover a winding, the more it moves the more the gauge moves.
Mark (mhpautos)
Sunday, September 5th, 2010 AT 6:32 PM