Table 1-72 (Continued) 7. With normal start, unstable idle speed during warm-up Common trouble location: 1. Fuel with water; 2. Coolant temperature sensor; 3. Spark plug; 4. Throttle body and idle speed by-pass air way; 5. Intake air way; 6. Idle speed regulator; 7. Mechanical part of the engine. Diagnosis Flow Table 1-73 94 S/N Operation Test Results Actions 7 Check the pressure for each cylinder of the engine. Are they great different? Yes Remove the mechanical troubles for the engine No Next step 8 Check if the ignition sequence and timing of the engine can meet with the standards. Yes Next step No Check and repair ignition timing 9 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 the spark plug for each cylinder. Check if its model and gap can meet with starndards. Yes Next step No Adjust or replace 3 Remove the idle speed regulator. Check the throttle body, idle speed regulator, and idle speed by-pass air way for carbon deposition.
Yes Wash relevant parts No Next step 4 Disconnect the coolant temperature sensor, and start the engine. Check the engine under warm-up for unstable idle speed. Yes Replace sensor No Next step