Inspection Procedure 5
INSPECTION PROCEDURE 5: Cranks, Won't StartCranks, Won't Start Circuit
- Refer to, Ignition circuit system.
CIRCUIT OPERATION
- Refer to, Ignition circuit system.
COMMENT
- In cases such as the above, the cause is probably no spark, fuel delivery, or fuel quality problems. In addition, foreign materials (water, kerosene, etc.) may be mixed with the fuel.
TROUBLESHOOTING HINTS (The most likely causes for this case:)
- Malfunction of the ignition system.
- Malfunction of the fuel pump system.
- Malfunction of the injector system.
- Malfunction of the ECM.
- Contaminated fuel.
DIAGNOSIS
Required Special Tools:
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: USB Cable
- MB991911: Main Harness B
STEP 1. Measure the battery positive voltage.
1. Measure the battery positive voltage during cranking.
- The voltage should remain greater than 8 volts while the engine is cranked.
Q: Does the voltage remain greater than 8 volts while the engine is cranked?
YES: Go to Step 2.
NO: Check the battery. Refer to, Battery - Battery check. Then confirm that the malfunction symptom is eliminated.
STEP 2. Check the timing belt for breaks.
Q: Is the timing belt good condition?
YES: Go to Step 3.
NO: Replace timing belt. Then confirm that the malfunction symptom is eliminated.
STEP 3. Using scan tool MB991958, check data list.
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. Check the following items in the data List. Refer to, Data List Reference Table. Data List Reference Table & Normal Scan Data Values
a. Item 16: Power Supply Voltage.
b. Item 22: Crankshaft Position Sensor.
c. Item 21: Engine Coolant Temperature Sensor.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Are they operating properly?
YES: Go to Step 4.
NO: Repair or replace it. 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, Actuator Test Reference Table. Actuator Test Reference Table
a. Item 07: 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 it. Then confirm that the malfunction symptom is eliminated.
STEP 5. Check the ignition system.
1. Connect the timing light to terminal No.1 of the ignition coil connectors B-103 or B-114, 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 6.
NO: Refer to INSPECTION PROCEDURE 33 - Ignition Circuit System.
STEP 6. Check the ignition timing.
1. Check the ignition timing at cranking.
Standard value: 5 degrees BTDC ± 3 degrees
Q: Is the ignition timing normal?
YES: Go to Step 7.
NO: Check that the crankshaft position sensor and timing belt cover are in the correct position. Then confirm that the malfunction symptom is eliminated.
STEP 7. Check harness connectors B-17 or B-18 or B-20 or B-22 at injector for damage.
Q: Is the harness connector in good condition?
YES: Go to Step 8.
NO: Repair or replace it. Then confirm that the malfunction symptom is eliminated.
STEP 8. Check the injector.
1. Disconnect the injector connectors B-17, B-18, B-20 and B-22.
2. Measure the resistance between each injector side connector terminal No.1 and No.2.
Standard value: 2 - 3 Ohms [at 20 degrees C (68 degrees F)]
Q: Is the resistance between 2 and 3 Ohms [at 20 degrees C (68 degrees F)]?
YES: Go to Step 9.
NO: Replace the injector. Then confirm that the malfunction symptom is eliminated.
STEP 9. Check connector C-121 at ECM for damage.
Q: Is the connector in good condition?
YES: Go to Step 10.
NO: Repair or replace it. Then confirm that the malfunction symptom is eliminated.
STEP 10. Check for harness damage between injector connector and ECM connector.
a. Check the harness wire between injector connector B-22 (terminal No.2) and ECM connector C-121 (terminal No.1) at No.1 cylinder.
b. Check the harness wire between injector connector B-20 (terminal No.2) and ECM connector C-121 (terminal No.9) at No.2 cylinder.
c. Check the harness wire between injector connector B-18 (terminal No.2) and ECM connector C-121 (terminal No.24) at No.3 cylinder.
d. Check the harness wire between injector connector B-17 (terminal No.2) and ECM connector C-121 (terminal No.2) at No.4 cylinder.
Q: Is the harness wire in good condition?
YES: Check the following items, and repair or replace the defective items.
a. Check the ignition coil, spark plugs and spark plug cables.
b. Check if the injectors are clogged.
c. Check if fuel is contaminated.
d. Check compression.
Then confirm that the malfunction symptom is eliminated.
NO: Repair it. Then confirm that the malfunction symptom is eliminated.