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Home >> Mitsubishi Truck >> 2000 >> Montero Sport LS 4WD V6-3.0L SOHC >> Repair and Diagnosis >> Powertrain Management >> Computers and Control Systems >> Testing and Inspection >> Symptom Related Diagnostic Procedures >> Inspection Procedure 6

Inspection Procedure 6

COMMENT
- In such cases as the above, the cause is usually improper air/fuel mixture. It is possible, though less likely, that the spark plugs are generating sparks but the sparks are weak.

TROUBLESHOOTING HINTS
The most likely causes for this case:
- Malfunction of the ignition system.
- Malfunction of the injector system.
- Foreign materials in fuel.
- Poor compression.
- Malfunction of the immobilizer system.
- Malfunction of the PCM.

DIAGNOSIS
Required Special Tool:
MB991502: Scan Tool (MUT-II)

STEP 1. Check the battery voltage.
1. Measure the battery voltage during cranking.
- The voltage should be 8 volts or more.

If the voltage is 8 volts or more, go to Step 2.

If the voltage is less than 8 volts, check the battery. Refer to Battery. Then confirm that the malfunction symptom is eliminated.

CAUTION: To prevent damage to the scan tool, turn the ignition switch "OFF" before connecting or disconnecting the scan tool.




STEP 2. Using scan tool MB991502, read the immobilizer system diagnostic trouble code (DTC).
If the immobilizer system DTC is output, refer to Ignition Switch and Immobilizer system.

If the immobilizer system DTC is not output, go to Step3.

CAUTION: To prevent damage to the scan tool, turn the ignition switch "OFF" before connecting or disconnecting the scan tool.




STEP 3. Using scan tool MB991502, read the diagnostic trouble code (DTC).
If DTC is not output, go to Step 4.

If DTC is output, refer to Diagnostic Trouble Code Chart.

CAUTION: To prevent damage to the scan tool, turn the ignition switch "OFF" before connecting or disconnecting the scan tool.




STEP 4. Using scan tool MB991502, check data list and actuator test.
1. Check the following items in the actuator test.
Refer to Actuator Test Reference Table.

a. Item 07: Fuel Pump.

2. Check the following items in the data list.
Refer to Data List Reference Table.

a. Item 21: Engine Coolant Temperature Sensor.
b. Item 18: Ignition Switch-ST

If the checks above meet the specifications, go to Step 5.

If the checks above do not meet the specifications, repair or replace. Then confirm that the malfunction symptom is eliminated.

STEP 5. Check the engine start-ability.
1. Depress the accelerator pedal slightly, and start the engine.

If the start-ability is good, go to Step 6.

If the start-ability is poor, go to Step 7.




STEP 6. Check the idle air control (IAC) motor operation sound.
1. Check that the engine coolant temperature is 20° C (68° F) or below.

NOTE: Disconnecting the engine coolant temperature sensor connector and connecting the harness side of the connector to another engine coolant temperature sensor that is at 20° C (68° F) or below is also okay.

2. Check the operation sound of the IAC motor can be heard after the ignition is switched "ON" (but without starting the engine).
- An operation sound is heard.

If no sound is heard, refer to DTC P0505 - Idle Control System Malfunction <3.0L Engine> or refer to DTC P0505 - Idle Control System Malfunction <3.5L Engine>.

If a sound is heard, carry out the following cleaning or adjustment.
- Clean the throttle valve area
- Check and adjust the fixed SAS <3.0L Engine>

After cleaning or adjusting, confirm that the malfunction symptom is eliminated.

STEP 7. Check the ignition timing.
1. Check the ignition timing during cranking.

Standard value: 5° BTDC 3°

If within specifications, go to Step 8.

If not within specifications, check that the crankshaft position sensor and timing belt cover are in the correct position. Then confirm that malfunction symptom is eliminated.

STEP 8. Check the injector operation sound.
1. Using a stethoscope or long flat-tipped screwdriver, check the operation sound ("tick-tick-tick") of injectors during cranking.

- Can the operating sound be heard?

If no, go to Step 9.

If yes, go to Step 12.





STEP 9. Check the power supply line at injector connectors A-70, A-71, A-72, A-73, A-74, A-75.
1. Disconnect connectors A-70, A-71, A-72, A-73, A-74, A-75 and measure at the harness side.
2. Turn the ignition switch "ON".
3. Measure current while connecting terminal 1 to ground via a 20-ohms resistor.

- Current should be 0.5 ampere or more.

4. Turn the ignition switch "OFF".

If 0.5 ampere or more, go to Step 10.

If less than 0.5 ampere, check intermediate connector A-04, and repair or replace if necessary. Refer to vehicle level Testing and Inspection. If connector A-04 is in good condition, repair the harness wire between MFI relay connector C-59 and injector connectors A-70, A-71, A-72, A-73, A-74, A-75. Then check that the malfunction is eliminated.




STEP 10. Check the circuits at PCM connector C-89.
1. Disconnect connector C-89 and measure at the harness side.
2. Disconnect PCM connector C-90. Using a jumper wire, connect terminal 49 to ground. Then operate the MFI relay.
3. Turn the ignition switch "ON".
4. Connect terminals 1, 2, 9, 10, 24, 25 to ground via a 20-ohms resistor to measure the current at each injector as follows:

Terminal 1 for the number 1 cylinder injector
Terminal 9 for the number 2 cylinder injector
Terminal 24 for the number 3 cylinder injector
Terminal 2 for the number 4 cylinder injector
Terminal 10 for the number 5 cylinder injector
Terminal 25 for the number 6 cylinder injector

- Current should be 0.3 ampere.







5. Turn the ignition switch "OFF".
If 0.3 ampere or more, go to Step 11.

If less than 0.3 ampere, check intermediate connector A-04. Repair or replace if necessary. Refer to vehicle level Testing and Inspection. If intermediate connector A-04 is in good condition, repair the harness wire between injector connectors A-70, A-71, A-72, A-73, A-74, A-75 and PCM connector C-89. Then check that the malfunction is eliminated.




STEP 11. Check harness connector C-89 at the PCM for damage.
If harness connector C-89 is in good condition, replace the injector.

If harness connector C-89 is damaged, repair or replace it. Refer to vehicle level Testing and Inspection.

Then check that the malfunction is eliminated.

STEP 12. Check the following items.
1. Check the following items, and repair or replace the defective items.

a. Check the ignition coil, spark plugs, spark plug cables.
b. Check if the injectors are clogged.
c. Check compression.
d. Check fuel lines for clogging.
e. Check if the foreign materials (water, kerosene, etc.) got into fuel.

Then confirm that the malfunction symptom is eliminated.

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