Voltage Values

25 Position ECU Plug:

The supply that feeds the air flow meter pin 9 also feeds the ECU pin 9, the fuel pump relay and the throttle switch common. The fuel pump relay is also the main relay. It is important to know that the main relay/fuel pump relay will not supply power unless it sees an start signal while cranking and an ignition signal once the engine starts.

GROUNDS
KEY ON
Pin 5 to G1 0 - 0.5V
Pin 5 to 13 0 - 0.5V
KEY OFF
Pin 5 to G1 0V
Pin 5 to 13 0V

MAIN RELAY SUPPLY
Pin 5 to 9
Key OFF 0V
Key ON 11 - 13V

COOLANT TEMPERATURE SENSOR
Pin 5 to 10
68°F 4.0 - 7.0V
176°F - 194°F 1.0 - 2.0V

THROTTLE SWITCH
Pin 5 to 2
Closed 8.0 - 13.0V
Opened 0.0 - 1.0V
Pin 5 to 3
Opened 0.0 - 1.0V
Full load 8.0 - 13.0V

AIR FLOW SENSOR
Key ON
Pin 5 to 9 (Supply) 11 - 13V
Pin 5 to 8 (Ref.) 6.0 - 10.0V
Pin 5 to 7 (Load) 0.5 - 1.0V
Engine Idling
Pin 5 to 9 (Supply) 13 - 14.5V
Pin 5 to 8 (Ref.) 7.5 - 12.0V
Pin 5 to 7 (Load) 5.0 - 6.0V

OXYGEN SENSOR
Pin 5 to 20
Key ON 0.4 - 0.5V
Engine Idling 0.1 - 0.8V

BARO SENSOR
Pin 5 to 11
KEY ON 1.5 - 3.5V

START SIGNAL
Pin 5 to 16
Key ON 0.0V
Cranking 10 - 11.5V