Engine Controls - Tests W/o Codes: Other Mitsubishi Montero II

DIFFICULT TO START/NO START (CRANKS OKAY)

1. Check idle speed control servo (if applicable).
2. Check stepper motor (if applicable).
3. Check ignition switch.
4. Check TDC sensor.
5. Check crankshaft position sensor.
6. Check inhibitor switch (A/T).
7. Check airflow sensor.
8. Check coolant temperature sensor.
9. Check idle position switch.
10. Check power supply to ECM ground.
11. Check fuel pressure.
12. Check for disconnected or damaged vacuum hoses.
13. Check for control relay malfunction.
14. Check for MPI system malfunction.
15. Check for fuel pump drive control system malfunction.
16. Check for ignition coil malfunction.
17. Check for ignition timing malfunction.
18. Check for power transistor malfunction.
19. Check for fuel injector malfunction.
20. Check for ECM malfunction.
21. Ensure electrical harness, connectors and wires are not broken or loose.

ROUGH OR UNSTABLE IDLE

1. Check intake air temperature sensor.
2. Check purge control solenoid valve (if applicable).
3. Check vehicle speed sensor.
4. Check engine coolant temperature sensor.
5. Check barometric pressure sensor.
6. Check ignition switch.
7. Check idle position switch.
8. Check throttle position sensor.
9. Check TDC sensor.
10. Check crankshaft position sensor.
11. Check power steering oil pressure switch.
12. Check A/C switch and power relay (if applicable).
13. Check inhibitor switch.
14. Check oxygen sensor.
15. Check airflow sensor.
16. Check motor position sensor (if equipped).
17. Check fuel pressure.
18. Check for disconnected or damaged vacuum hoses.
19. Check MPI system malfunction.
20. Check for stepper motor malfunction (if applicable).
21. Check for fuel injector malfunction.
22. Check for power transistor malfunction.
23. Check for vehicle speed switch malfunction.
24. Check for ECM malfunction.
25. Ensure electrical harness, connectors and wires are not broken or loose.

ENGINE HESITATES OR POOR ACCELERATION

1. Check intake air temperature sensor.
2. Check engine coolant temperature sensor.
3. Check barometric pressure sensor.
4. Check ignition switch.
5. Check ignition coil.
6. Check EGR control solenoid valve (if applicable).
7. Check idle position switch.
8. Check throttle position sensor.
9. Check TDC sensor.
10. Check crankshaft position sensor.
11. Check power steering oil pressure switch.
12. Check A/C switch (if applicable).
13. Check inhibitor switch (A/T).
14. Check oxygen sensor.
15. Check airflow sensor.
16. Check motor position sensor (if applicable).
17. Check fuel pressure.
18. Check for disconnected or damaged vacuum hoses.
19. Check for MPI system malfunction.
20. Check for stepper motor malfunction (if applicable).
21. Check for fuel injector malfunction.
22. Check for power transistor malfunction.
23. Check for A/C power relay control system malfunction.
24. Check for ECM malfunction.
25. Ensure electrical harness, connectors and wires are not broken or loose.

ENGINE SURGES

1. Check coolant temperature sensor.
2. Check idle position switch.
3. Check EGR control solenoid valve (if applicable).
4. Check fuel pressure.
5. Check for fuel injector malfunction.

DETONATION OR KNOCKING

1. Check airflow sensor.
2. Check for cooling system problems.
3. Check fuel quality.
4. Check intake air temperature sensor.
5. Check barometric pressure sensor.
6. Check ignition coil.
7. Check power transistor.
8. Check for EGR system malfunction.

POOR FUEL MILEAGE

1. Check intake air temperature sensor.
2. Check engine coolant temperature sensor.
3. Check barometric pressure sensor.
4. Check ignition switch.
5. Check idle position switch.
6. Check throttle position sensor.
7. Check TDC sensor.
8. Check crankshaft position sensor.
9. Check power steering oil pressure switch.
10. Check A/C switch (if applicable).
11. Check inhibitor switch (A/T).
12. Check oxygen sensor.
13. Check airflow sensor.
14. Check motor position sensor (if applicable).
15. Check fuel pressure.
16. Check for MPI system malfunction.
17. Check for stepper motor malfunction.
18. Check for fuel injector malfunction.
19. Check for power transistor malfunction.

Intermittent Simulation

To reproduce conditions creating an intermittent fault, use following methods

1. Lightly vibrate component.
2. Heat component.
3. Wiggle or bend wiring harness.
4. Spray component with water mist.
5. Remove/apply vacuum source. Monitor circuit/component voltage or resistance while simulating intermittent. If engine is running, monitor for self-diagnostic codes. Use test results to identify a faulty component or circuit.