Throttle Position Sensor Adjustment MFI

1. Remove the air cleaner and any hoses that allow access to the throttle position (TP) sensor.
2. Disconnect the TP sensor connector.
3. Insert the jumper wires between the TP sensor and the harness.
4. Turn the ignition ON, leaving the engine OFF.




Important: The TP sensor voltage is displayed by the scan tool. It is recommended that only the multimeter (DMM) be used to set the TP sensor as the scan tool voltage may read higher than the digital multimeter (DMM).

5. Use the DMM in order to measure the voltage from the TP sensor connector terminals A to C. This is a voltage reference.
6. Multiply the voltage ratio by the voltage reference number (from step 5 ) which equals the desired TP sensor voltage setting. For example, 0.33 (voltage ratio) multiplied by 4.97 (voltage reference) equals 1.64  volts. (desired voltage setting).



7. Insert the 0.646 side of the TP sensor gauge block between the gauge boss on the injector pump and the wide-open stop screw on the throttle lever.
8. Rotate the throttle lever toward the wide-open position so that the gauge block is held firmly in place.
9. Measure the voltage between terminals B and C. This is the TP sensor voltage. The TP sensor voltage should be within plus or minus 0.02 volts of the desired TP sensor voltage setting. For example, the actual TP sensor voltage should be between 1.62 and 1.66 volts.
10. If the TP sensor voltage is within tolerance, proceed to step 14.
11. In order to adjust the TP sensor, loosen the 2 attaching screws and rotate the TP sensor to its full left position (facing the sensor).

Important: In order to obtain the correct position, the sensor must be rotated to the right from its full left position.

12. Rotate the sensor to the right until you obtain the desired sensor voltage setting.
13. When you obtain the correct voltage, hold the sensor and tighten the attaching screws to 6 N·m (53 lb in).
14. Release the throttle lever. Allow the lever to return to the idle position.
15. Open the throttle lever back against the gauge block. Re-check the TP sensor. The TP sensor voltage must be within plus or minus 0.02 volts of the desired TP sensor voltage. Return to step 11 if an adjustment is necessary.
16. Once the TP sensor has been set, check the wide-open throttle (WOT) voltage setting.
17. Multiply the WOT voltage ratio by the voltage reference from step 5 which equals the required WOT voltage. For example, 0.90 (WOT voltage ratio) multiplied by 4.97 (voltage reference) equals 4.47 (WOT voltage).
18. In order to measure the actual WOT voltage, remove the gauge block tool. Move the throttle to the wide open position and check the voltage. It must be within the following WOT voltage setting tolerance for the TP sensor specified. The acceptable WOT voltage is between 4.22 to 4.72 volts.
19. If an adjustment is not possible or if the sensor voltage at the WOT position is not within the acceptable range, replace the TP sensor and repeat the adjustment procedure.
20. Turn the ignition switch to OFF.
21. Remove the jumper wires and reconnect the TP sensor to the vehicle wiring harness.
22. Reinstall the air cleaner and the hoses.