Inspection Procedure 6
Inspection Procedure 6: Hard StartingCOMMENT
- In cases such as the above, the cause is usually either weak spark, improper air-fuel mixture or low compression.
TROUBLESHOOTING HINTS (The most likely causes for this case:)
- Malfunction of the fuel pump system.
- Malfunction of the ignition system.
- Malfunction of the injector system.
- Poor compression
- Malfunction of the EGR system
- Contaminated fuel.
- Malfunction of the ECM.
DIAGNOSIS
Required Special Tools:
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: USB Cable
- MB991910: Main Harness A
STEP 1. Check if the EGR valve sounds during initialization.
Q: Is the initialization sound heard in the EGR valve?
YES : Go to Step 2.
NO : Refer to Emission Control-Exhaust Gas Recirculation (EGR) System-EGR Valve (Stepper Motor) Check. Component Tests and General Diagnostics
STEP 2. Using scan tool MB991958, read the diagnostic trouble code (DTC).
CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
1. Connect scan tool MB991958 to the data link connector.
2. Turn the ignition switch to the "ON" position.
3. Read the DTC.
4. Turn the ignition switch the "LOCK" (OFF) position.
Q: Is any DTC set?
YES : Refer to MFI Diagnostic Trouble Code Chart. Diagnostic Trouble Code Descriptions
NO : Go to Step 3.
STEP 3. Using scan tool MB991958, check data list.
1. Turn the ignition switch the "ON" position.
2. Check the following items in the data list. Refer to MFI Data List Reference Table. Datal List Reference Table
a. Item 1: Power Supply Voltage (at Cranking)
b. Item 6: Engine Coolant Temperature Sensor.
3. Turn the ignition switch the "LOCK" (OFF) position.
Q: Is the sensor operating properly?
YES : Go to Step 4.
NO : Repair or Replace. Then confirm that the malfunction symptom is eliminated.
STEP 4. Using scan tool MB991958, check actuator test.
1. Turn the ignition switch to the "ON" position.
2. Check the following items in the actuator test. Refer to MFI Actuator Test Reference Table. Actuator Test Reference Table
a. Item 9: Fuel Pump.
3. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the actuator operating properly?
YES : Go to Step 5.
NO : Repair or Replace. Then confirm that the malfunction symptom is eliminated.
STEP 5. Check the ignition timing.
1. Check the ignition timing at cranking.
Standard value: 5° BTDC ± 3°
Q: Is the ignition timing normal?
YES : Go to Step 6.
NO : Check for installed conditions of the timing belt. Then confirm that the malfunction symptom is eliminated.
STEP 6. Check the fuel pressure.
Refer to MFI On-vehicle Service-Fuel Pressure Test. Testing and Inspection
Q: Is the fuel pressure normal?
YES : Go to Step 7.
NO : Check the following items, and repair or replace the defective items.
- Insufficient fuel pump discharge.
- Fuel pump filter clogged.
STEP 7. Check the left bank injector resistance.
1. Disconnect the left bank injector connector B-115, B-116, B-120.
2. Measure the resistance between each injector side connector terminal No. 1 and No. 2.
Standard value: 10.5 - 13.5 ohms [at 20 °C (68 °F)]
Q: Is the measured resistance between 10.5 and 13.5 ohms [at 20 °C (68 °F)]?
YES : Go to Step 8.
NO : Replace the faulty injector. Then confirm that the malfunction symptom is eliminated.
STEP 8. Check the right bank injector resistance at intermediate connector B-21.
1. Disconnect the intermediate connector B-21.
2. Measure the resistance between each male connector side terminal.
a. Measure the resistance between terminal No. 6 and No. 7 at No. 1 cylinder injector.
b. Measure the resistance between terminal No. 6 and No. 8 at No. 3 cylinder injector.
c. Measure the resistance between terminal No. 6 and No. 9 at No. 5 cylinder injector.
- Resistance should be between 10.5 and 13.5 ohms [at 20 °C (68 °F)].
Q: Is the measured resistance between 10.5 and 13.5 ohms [at 20 °C (68 °F)]?
YES : Go to Step 11.
NO : Go to Step 9.
STEP 9. Check the right bank injector resistance.
1. Remove the intake manifold.
2. Disconnect the right bank injector connector, which deviates from the standard value at Step 8.
3. Measure the resistance between injector side connector terminal No. 1 and No. 2.
Standard value: 10.5 - 13.5 ohms [at 20 °C (68 °F)]
Q: Is the measured resistance between 10.5 and 13.5 ohms [at 20 °C (68 °F)]?
YES : Go to Step 10.
NO : Replace the injector. Then confirm that the malfunction symptom is eliminated.
STEP 10. Check harness connector B-101, B-103, B-104 at right bank injector for damage.
1. Check the injector connector, which deviated from the standard value listed in Step 8.
Q: Is the harness connector in good condition?
YES : Repair harness wire between injector intermediate connector and right bank injector connector because of harness damage. Then confirm that the malfunction symptom is eliminated.
NO : Repair or replace it. Refer to General (Electrical), Harness Connector Inspection. Then confirm that the malfunction symptom is eliminated.
STEP 11. Check harness connector B-21 at the intermediate connector for damage.
Q: Is the harness connector in good condition?
YES : Go to Step 12.
NO : Repair or replace it. Refer to General (Electrical), Harness Connector Inspection. Then confirm that the malfunction symptom is eliminated.
STEP 12. Check harness connector B-10 at ECM and harness connector B-115, B-116, B-120 at the left bank injector for damage.
Q: Is the harness connector in good condition?
YES : Go to Step 13.
NO : Repair or replace it. Refer to General (Electrical), Harness Connector Inspection. Then confirm that the malfunction symptom is eliminated.
STEP 13. Check for harness damage between injector connector and ECM connector.
1. Disconnect the injector connector and ECM connector.
2. Measure the resistance between injector connector and ECM connector.
a. Injector connector B-101 (terminal No. 2) and ECM connector B-10 (terminal No. 2) at No. 1 cylinder injector.
b. Injector connector B-120 (terminal No. 2) and ECM connector B-10 (terminal No. 3) at No. 2 cylinder injector.
c. Injector connector B-103 (terminal No. 2) and ECM connector B-10 (terminal No. 18) at No. 3 cylinder injector.
d. Injector connector B-116 (terminal No. 2) and ECM connector B-10 (terminal No. 19) at No. 4 cylinder injector.
e. Injector connector B-104 (terminal No. 2) and ECM connector B-10 (terminal No. 50) at No. 5 cylinder injector.
f. Injector connector B-115 (terminal No. 2) and ECM connector B-10 (terminal No. 51) at No. 6 cylinder injector.
Q: Is the measured resistance less than 2 ohms?
YES : Go to Step 14.
NO : Repair it. Then confirm that the malfunction symptom is eliminated.
STEP 14. Check the ignition system.
1. Connect the timing light to terminal No. 3 of the ignition coil connector B-01, B-04, B-05, B-15, B-18 or B-19 in order.
2. Crank the engine.
- The timing light flashes.
3. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Does the timing light flash?
YES : Go to Step 15.
NO : Refer to MFI INSPECTION PROCEDURE 24-Ignition Circuit System. Inspection Procedure 24
STEP 15. Check the spark plugs.
Refer to Engine Electrical, Ignition System-On-vehicle Service-Spark Plug Check And Cleaning.
Q: Are there any abnormalities?
YES : Replace the spark plug. Then confirm that the malfunction symptom is eliminated.
NO : Go to Step 16.
STEP 16. Check the ignition coil.
1. Remove the intake manifold.
2. Refer to Engine Electrical, Ignition System-On-vehicle Service-Ignition Coil Check.
Q: Are there any abnormalities?
YES : Replace the ignition coil. Then confirm that the malfunction symptom is eliminated.
NO : Go to Step 17.
STEP 17. Check the compression pressure.
Refer to Engine Mechanical, On-vehicle Service-Compression Pressure Check.
Q: Is the compression pressure normal?
YES : Check the following items, and repair or replace the defective items.
a. Check if fuel is contaminated.
b. Check if the injectors are clogged.
Then confirm that the malfunction symptom is eliminated.
NO : Repair it. Then confirm that the malfunction symptom is eliminated.