Accord 1985-89 and Prelude 1986-89
Check the following elements of the system before checking the idle speed: ignition timing, valve clearance and CO content in the exhaust at idle.
1. If the engine will run, disconnect the injector connectors with the engine idling, paying attention to the change in idle speed. The idle speed should drop equally for each cylinder.
2. Listen to the clicking sound of each injector with a stethoscope while the engine is idling.
3. If any injector makes clicks typical of a failed injector, check the wiring between the computer and the injector. The voltage at the injector connector should vary between 0-2 V. If the voltage is OK, replace the injector.
4. If the engine does not start, remove the injector connector and measure the resistance between the injector terminals. The resistance should be 1.5-2.5 ohms.
5. If the resistance is different, replace the injector. If the resistance is normal, check the wiring between the resistor and the injector, as well as between the resistor and the computer.