- Check to ensure rubber boot is correctly positioned in its groove on ISA motor shaft. If not, correct its position and recheck vehicle for proper idle speed operation.
- If correctly positioned, continue diagnosis procedure. Open throttle and attempt to extend and retract ISA motor. Push and pull axially (in and out) on ISA motor shaft.
NOTE:
If shaft axial movement is greater than .75" (9.5 mm), replace ISA motor.
- Ensure ignition switch is in the "OFF" position. Connect ISA Exerciser Tool (Ele.AB.99) leads to vehicle battery (Red to positive and Black to negative).
- Disconnect ISA motor connector. Connect ISA motor exerciser 4-pin connector to ISA motor (it may be necessary to slot casing of one of exerciser pins to connect exerciser to ISA motor).
- Inspect ISA motor tip position. ISA motor tip should be in contact with throttle lever. Throttle should be partially open. If ISA motor tip position is okay, go to step 10).
- If ISA motor tip is not in contact with throttle lever and throttle is closed, motor is fully retracted and jammed. Go to next step.
- Apply parking brake and start engine. With engine running at approximately 1500 RPM, move exerciser switch to the "EXTEND" position several times to free ISA motor.
- Turn ignition switch to the "OFF" position. ISA motor tip should be in contact with throttle lever. Throttle should be partially open.
- IF ISA motor tip is not in contact with throttle lever and throttle is still closed, motor is permanently jammed. Replace ISA motor. If ISA motor is functioning properly, go to next step.
- Move exerciser switch to the "EXTEND" position for 5 seconds. Watch ISA motor action. ISA motor should ratchet (click) several times when it has reached fully extended position. If ISA motor is functioning as indicated, go to next step. If motor does not ratchet (click), replace ISA motor.
- Move exerciser switch to the "RETRACT" position for 5 seconds. ISA motor should close throttle and stop automatically in 3 seconds.
NOTE:
The Closed throttle light on exerciser tool will go out when ISA motor reaches closed throttle position.
- Tip of ISA motor should be in contact with, or no more than .20" (.5 mm) away from throttle lever when motor movement stops.
NOTE:
Throttle lever should also be in contact with throttle stop screw on main body of TBI when ISA motor movement stops.
- If ISA motor functioned as indicated, go to step 17). If ISA motor did not move as indicated, replace ISA motor. If ISA motor closed throttle, but ratcheted away from throttle lever and was no longer in contact with throttle lever, replace ISA motor.
- If ISA motor moved throttle, but throttle was not in contact with closed throttle stop screw on TBI main body when ISA motor movement stopped, go to next step.
- Push throttle lever closed while pressing exerciser switch in the "RETRACT" position for 5 seconds. ISA motor should continue to retract until throttle lever contacts with closed throttle stop screw on TBI main body.
- If ISA motor is functioning as indicated, ISA motor is okay. Check throttle control system for freedom and smoothness of movement. Inspect throttle return springs. Repair as required. After repair, go to next step.
- Move ISA motor to the "EXTEND" and "RETRACT" position 2 or 3 times. Always leave ISA motor extended. ISA motor should operate smoothly. A ratchet (click) sound should be heard until end of ISA travel. It should stop automatically at end of ratchet level.
- If ISA motor is functioning as indicated, motor is okay. If ISA motor movement is intermittent, slow, or gritty sounding, replace ISA motor.
- Disconnect ISA motor exerciser connector from ISA motor and battery. Reconnect harness connector to ISA motor.