Inspection Procedure 6

Inspection procedure 6: Hard starting

COMMENT

- 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:)

- Fuel pump system failed.

- Ignition system failed.

- Injector system failed.

- Poor compression.

- Contaminated fuel.

- ECM failed.

DIAGNOSIS

Required Special Tool:

- 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 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.
1. Item 1: Power Supply Voltage

2. Item 6: Engine Coolant Temperature Sensor

(3)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the sensor 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 actuator test.

(1)Turn the ignition switch to the "ON" position.

(2)Check the following item in the actuator test. Refer to Actuator Test Reference Table Actuator Test Reference Table.
3. Item 9: Fuel Pump

(3)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the actuator operating properly?

YES Go to Step 4.
NO Repair or replace it. Then confirm that the malfunction symptom is eliminated.
STEP 4. Check the ignition timing.

Testing and Inspection.

Q. Is the ignition timing normal?

YES Go to Step 5.
NO Repair or replace it. Then confirm that the malfunction symptom is eliminated.
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 it. Then confirm that the malfunction symptom is eliminated.
STEP 6. Check harness connector B-101, B-102, B-103 and B-104 at injector for damage.

Q. Are the harness connectors in good condition?

YES Go to Step 7.
NO Repair or replace them. Harness Connector Inspection.
Then confirm that the malfunction symptom is eliminated.
STEP 7. Check the injector.

(1)Disconnect the injector connectors B-101, B-102, B-103, B-104.





(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 harness connector A-21X at injector relay for damage.

Q. Is the harness connector in good condition?

YES
Go to Step 9.

NO Repair or replace it. Harness Connector Inspection.
Then confirm that the malfunction symptom is eliminated.
STEP 9. Check for harness damage between injector relay connector and injector connector.

NOTE:
Check harness after checking intermediate connector A-60. If intermediate connector is damaged, repair or replace it. Harness Connector Inspection. Then confirm that the malfunction symptom is eliminated.

4. Check the harness wire between injector relay connector A-21X (terminal No. 3) and injector connector B-101 (terminal No. 1) at No. 1 cylinder injector.

5. Check the harness wire between injector relay connector A-21X (terminal No. 3) and injector connector B-102 (terminal No. 1) at No. 2 cylinder injector.

6. Check the harness wire between injector relay connector A-21X (terminal No. 3) and injector connector B-103 (terminal No. 1) at No. 3 cylinder injector.

7. Check the harness wire between injector relay connector A-21X (terminal No. 3) and injector connector B-104 (terminal No. 1) at No. 4 cylinder injector.

Q. Are the harness wires in good condition?

YES Go to Step 10.
NO Repair them. Then confirm that the malfunction symptom is eliminated.
STEP 10. Check harness connector B-108 at ECM for damage.

Q. Is the harness connector in good condition?

YES Go to Step 11.
NO Repair or replace it. Harness Connector Inspection.
Then confirm that the malfunction symptom is eliminated.
STEP 11. Check for open circuit, short circuit to ground and harness damage between injector connector and ECM connector.

8. Check the harness wire between injector connector B-101 (terminal No. 2) and ECM connector B-108 (terminal No. 2) at No. 1 cylinder injector.

9. Check the harness wire between injector connector B-102 (terminal No. 2) and ECM connector B-108 (terminal No. 3) at No. 2 cylinder injector.

10. Check the harness wire between injector connector B-103 (terminal No. 2) and ECM connector B-108 (terminal No. 18) at No. 3 cylinder injector.

11. Check the harness wire between injector connector B-104 (terminal No. 2) and ECM connector B-108 (terminal No. 19) at No. 4 cylinder injector.

Q. Are the harness wires in good condition?

YES Go to Step 12.
NO Repair them. Then confirm that the malfunction symptom is eliminated.
STEP 12. Check the ignition system.

(1)Connect the timing light to terminal No. 4 of the ignition coil connectors B-01, B-02, B-03 or B-04 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 13.
NO Refer to, Inspection Procedure 26 - Ignition Circuit System Inspection Procedure 26.
STEP 13. 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 14.
STEP 14. 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 15.
STEP 15. Check the compression pressure.

Testing and Inspection.

Q. Is the compression pressure normal?

YES
Check the following items, and repair or replace the defective items.
12. Check if fuel is contaminated.

13. 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.