ENGINE WILL NOT START
Check spark and fuel systems as outlined in BASIC TESTING and SYSTEM/COMPONENT TESTS articles in the ENGINE PERFORMANCE Section. Test ECM power and ground circuits. Check TDC/CKP/CYP sensor and ignition output circuits.
DIFFICULT COLD START
Check coolant temperature, MAP, and TDC/CKP/CYP sensor circuits for malfunctions.
ROUGH IDLE WHEN WARM
Check Idle Air Control (IAC) valve, MAP sensor, fuel injectors, and EGR system for proper operation.
IDLE RPM HIGH WHEN WARM
Check idle adjuster screw. Check Idle Air Control (IAC) valve, fast idle valve, Engine Coolant Temperature (ECT) sensor, vacuum hose connections, and A/C signal circuit.
IDLE RPM LOW WHEN WARM
Check idle adjuster screw. Check Idle Air Control (IAC) valve, fuel injector circuit, A/C signal circuit, oil pressure switch, A/T position signal, and Electrical Load Detector (ELD). Check lock-up control solenoid circuit (if equipped).
STALLING DURING WARM-UP
Check Idle Air Control (IAC) valve, fast idle valve, and fuel system. Check Engine Coolant Temperature (ECT) sensor.
STALLING AFTER WARM-UP
Check fuel system, Idle Air Control (IAC) valve, and EGR control system.
LACK OF POWER
Check fuel supply system. Check MAP sensor, throttle position sensor, fuel injectors, air intake system, and catalytic converter. Check Variable Valve Timing (VTEC) control solenoid valve and oil pressure switch operation (if equipped).
Intermittent Simulation
To reproduce conditions creating an intermittent problem, use following methods
- Lightly vibrate component.
- Heat component.
- Wiggle or bend wiring harness.
- Spray component with water mist.
- Remove/apply vacuum source.
Monitor circuit/component voltage or resistance while simulating intermittent. If engine is running, monitor for self-diagnostic codes. Use test results to identify a defective component or circuit.