Inspection Procedure 11
Inspection procedure 11: When the engine is hot, it stalls at idle (die out)
COMMENT
- In cases such as the above, the ignition system, air/fuel mixture or compression pressure may be faulty. In addition, if the engine suddenly stalls, the cause may also be a connector damage.
TROUBLESHOOTING HINTS (The most likely causes for this case:)
- Malfunction of the fuel pump system.
- Malfunction of the ignition system.
- Poor compression
- Improper operation of the PCV valve.
- Vacuum leak.
- Dirtiness around throttle valve.
- 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. 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 to the "LOCK" (OFF) position.
Q. Is any DTC set?
YES Refer to Diagnostic Trouble Code Chart Multiport Fuel Injection (MFI).
NO Go to Step 2.
STEP 2. Using scan tool MB991958, check actuator test item 1: injector.
(1)Turn the ignition switch to the "ON" position.
(2)Check following items in the actuator test. Refer to Actuator Test Reference Table Actuator Test Reference Table.
1. Item 1: Injector.
(3)Turn the ignition switch to the "LOCK" (OFF) position.
Q. Are they operating properly?
YES Go to Step 3.
NO Repair or replace it. Then confirm that the malfunction symptom is eliminated.
STEP 3. Using scan tool MB991958, check data list.
(1)Turn the ignition switch to the "ON" position.
(2)Check the following items in the data list. Refer to Data List Reference Table Data List Reference Table.
2. Item 5: Intake Air Temperature Sensor.
3. Item 6: Engine Coolant Temperature Sensor.
4. Item 13: Throttle position sensor (main).
(3)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. Inspection of throttle body (throttle valve area) for dirtiness.
Q. Is the throttle valve area dirty?
YES Refer to On-vehicle Service - Throttle Body (Throttle Valve Area) Cleaning Throttle Body Cleaning.
NO Go to Step 5.
STEP 5. Check the fuel pressure.
Refer to Fuel Pressure Test Testing and Inspection.
Q. Is the fuel pressure normal?
YES Go to Step 6.
NO Repair or replace it. Then confirm that the malfunction symptom is eliminated.
STEP 6. Check the ignition timing.
Testing and Inspection.
Q. Is the ignition timing normal?
YES Go to Step 7.
NO Check for installed conditions of the timing chain. Then confirm that the malfunction symptom is eliminated.
STEP 7. Check the spark plugs.
Procedures.
Q. Are there any abnormalities?
YES Replace the spark plug. Then confirm that the malfunction symptom is eliminated.
NO Go to Step 8.
STEP 8. Check the ignition coil.
Testing and Inspection.
Q. Are there any abnormalities?
YES Replace the ignition coil. Then confirm that the malfunction symptom is eliminated.
NO Go to Step 9.
STEP 9. Check the compression pressure.
Testing and Inspection.
Q. Is the compression pressure normal?
YES Go to Step 10.
NO Repair it. Then confirm that the malfunction symptom is eliminated.
STEP 10. Check the positive crankcase ventilation system.
Crankcase Ventilation System Check.
Q. Is the positive crankcase ventilation system?
YES Go to Step 11.
NO Repair it. Then confirm that the malfunction symptom is eliminated.
STEP 11. Engine stall reproduction test.
Q. Is it easy to reproduce the engine stall?
YES
Check the following items, and repair or replace the defective items.
5. Vacuum leak.
6. Check if fuel is contaminated.
7. Check if the injectors are clogged.
8. Check if the foreign materials (water, kerosene, etc.) got into fuel.
Then confirm that the malfunction symptom is eliminated.
NO
Check if the following signals change suddenly by wiggling the circuit harness and connectors.
9. Crankshaft position sensor signal.
10. Mass airflow sensor signal.
11. Injector drive signal.
12. Primary and secondary ignition signal.
13. Fuel pump drive signal.
14. ECM power supply voltage.
Then confirm that the malfunction symptom is eliminated.