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Inspection Procedure 7

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:
- Malfunction of the ignition system.
- Malfunction of the injector system.
- Poor fuel quality.
- Poor compression.

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

STEP 1. Check the battery voltage.
1. Measure the battery voltage during cranking.
- The voltage is 8 volts or more.
If the voltage should be 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 diagnostic trouble code (DTC).
If DTC is not output, go to Step 3.
If DTC is output, go to Trouble Code Diagnostic Procedures.

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, check data list and actuator test.
1. Check the following items in the actuator test.
Actuator Test Reference Table
a. Item 07: Fuel Pump.
2. Check the following items in the data list.
Data List Reference Table & Normal Scan Data Values
a. Item 21: Engine Coolant Temperature Sensor.
b. Item 18: Ignition Switch-ST.
If the checks above meet the specifications, go to Step 4. If the checks above do not meet the specifications, repair or replace. Then confirm that the malfunction symptom is eliminated.

STEP 4. Check the ignition timing.
1. Check the ignition timing at cranking.

Standard value: 5° ± 3°

If within specifications, go to Step 5.
If not within specifications, check that the crankshaft position sensor and timing belt cover are in the correct position. Then check that the malfunction is eliminated.




STEP 5. Check the circuits at the PCM connector C-39.
1. Disconnect the PCM connector C-39 and measure at the harness side.




2. Disconnect the PCM connector C-40. Using a jumper wire, connect the terminal 49 to ground and activate the MFI relay.
3. Turn the ignition switch "ON."




4. Connect the terminals 1, 2, 9, 10, 24 and 25 to ground via a 20-Ohm resistor. Measure the current at this time. The PCM terminals correspond to the injectors as follows.
a. PCM terminals 1 when measuring number 1 cylinder injector.
b. PCM terminals 9 when measuring number 2 cylinder injector.
c. PCM terminals 24 when measuring number 3 cylinder injector.
d. PCM terminals 2 when measuring number 4 cylinder injector.
e. PCM terminals 10 when measuring number 5 cylinder injector.
f. PCM terminals 25 when measuring number 6 cylinder injector.
- The current should be 0.3 ampere or more.
5. Turn the ignition switch "OFF."
If not within specifications, go to Step 6.
If within specifications, check the PCM connector C-39, and repair or replace as required. Refer to Harness Connector Inspection >. If the PCM connector C-39 is in good condition, go to Step 9.

STEP 6. Check the power supply line at the injector connectors B-17, B-19, B-21, B-22, B-25, B-30).




1. Disconnect the connectors B-17, B-19, B-21, B-22, B-25, B-30 and measure at the harness side.
2. Turn the ignition switch "ON."




3. Connect the terminal 1 to ground via a 20-Ohm resistor. Measure the current at this time.
- The current should be 0.5 ampere or more.
4. Turn the ignition switch "OFF."
If within specifications, go to Step 7.
If not within specifications, check the intermediate connector B-26, and repair or replace as required. Refer to Harness Connector Inspection >. If the intermediate connector B-26 is in good condition, repair the harness wire between MFI relay connector A-21X and injector connectors B-17, B-19, B-21, B-22, B-25, B-30. Then check that the malfunction is eliminated.




STEP 7. Check the injector.
1. Disconnect the injector connector.
2. Measure the resistance between each injector side connector terminals 1 and 2.

Standard value: 13 - 16 Ohm [at 20° C (68° F)]

If within specifications, go Step 8.
If not within specifications, replace the injector. Then check that the malfunction is eliminated.




STEP 8. Check the harness connectors B-17, B-19, B-21, B-22, B-25, B-30 at the injector for damage.
If the harness connectors B-17, B-19, B-21 B-22, B-25, B-30 are damaged, repair or replace them. Refer to Harness Connector Inspection >.
If the harness connectors B-17, B-19, B-21, B-22, B-25, B-30 are in good condition, check the intermediate connector B-26, and repair or replace as required. Refer to Harness Connector Inspection >. If the intermediate connector B-26 is in good condition, repair the harness wires between the PCM connectors C-39 and the injector connectors B-17, B-19, B-21, B-22, B-25, B-30.
Then check the malfunction is eliminated.

STEP 9. 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 the compression.
d. Check if the foreign materials (water, kerosene, etc.) got into fuel.
Then check the malfunction is eliminated.
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