Fuel System

SINGLE POINT FUEL INJECTION (SPFI) SYSTEM

Throttle Position Sensor

1. Disconnect the negative battery cable.
2. Scribe alignment marks on the sensor and throttle body assembly. Remove the 2 screws securing the throttle sensor to the throttle body.
3. Disconnect the throttle sensor electrical harness.
4. Remove the throttle sensor by pulling it in the axial direction of the throttle shaft.
5. Remove the throttle sensor O-ring and discard.

To install:

6. Using a new throttle sensor O-ring, align and install the throttle sensor. Hand-tighten the screw.
7. Connect the throttle sensor electrical harness.
8. Connect the negative battery cable.
9. Adjust the throttle sensor.

Adjustment

Fig. 1: Checking continuity between terminals A and B

Fig. 2: Check for continuity after inserting a thickness gauge between the stopper screw and stopper

1. Using an ohmmeter, check that continuity exists between terminals A and B, when the throttle is fully closed, and that no continuity exists when the throttle is fully opened.
2. Adjust the throttle sensor by turning it slowly.
3. Insert a feeler gauge (thickness gauge) of 0.0122 in. (0.31mm) between the stopper screw on the throttle chamber and the stopper (this corresponds to the throttle opening of 1.0 degree). Ensure that continuity exists between terminals A and B.
4. Insert a feeler gauge (thickness gauge) of 0.0311 in. (0.79mm) between the stopper screw on the throttle chamber and the stopper (this corresponds to a throttle opening of 2.5 degrees). Ensure that continuity exists between terminals A and B.
5. If above specifications are not as specified, loosen the throttle sensor attaching screws, then turn the throttle sensor body until the correct adjustment is obtained.

Fig. 3: Check continuity between terminals B and D, then terminals B and C

1. Using an ohmmeter, measure resistance between terminals B and D, then between B and C (changes with the opening of the throttle valve).
2. The ohmmeter should read 3.5-6.5 kilo-ohms between terminals B and D.
3. Check that the ohmmeter reading between terminals B and C is less than 1 kilo-ohm with the throttle valve fully closed, and 2.4 kilo-ohms with the throttle valve fully opened.
4. When the throttle valve is moved from the fully closed to the fully opened position, check that resistance between terminals B and C increases continuously.
5. When the throttle valve is moved from the fully opened to the fully closed position, check that resistance between terminals B and C decreases continuously.
6. If any of the above faults are noted, replace the throttle sensor.

END OF SECTION