Table 1-71 (Continued) 6. With normal start, unstable idle speed at any time Common trouble location: 1. Fuel with water; 2. Fuel injector; 3. Spark plug; 4. Throttle body and idle speed by-pass air way; 5. Intake air way; 6. Idle speed regulator; 7. Ignition timing; 8. Spark plug; 9. Mechanical part of engine. Diagnosis Flow Table 1-72 93 S/N Operation Test Results Actions 10 Check if the ignition sequence and timing of the engine can meet with the standards. Yes Next step No Check and repair ignition timing 11 Connect the electronic injection system adapter. Turn on the ignition switch. Check the power supply of the pin 12#, 13#, 44#, 45#, 63#.
Check the grounding of the pin 3#, 51#, 53#, 61#, 80#. Are they OK? Yes Diagnosis help No Check and repair relevant line S/N Operation Test Results Actions 1 Check the air filter for blockage and the intake air way for leakage. Yes Check and repair air intake system No Next step 2 Check if the idle speed regulator is blocked. Yes Wash and replace No Next step 3 Check the spark plug for each cylinder. Check if its model and gap can meet with starndards. Yes Next step No Adjust or replace 4 Check the throttle body and idle speed by-pass air way for carbon deposition. Yes Wash No Next step 5 Remove the fuel injector.
Check the fuel injector for leakage, blockage or abnormal flow with a special fuel injector cleaner & analyzer. Yes Remove the trouble No Next step 6 Check the fuel for normal operation. Yes Replace fuel No Next step