Fuel Injection System - PGM-FI System: Testing: Injector

NOTE: Check idle speed, ignition timing, valve clearance and idle CO % before performing test.

For Civic (standard) with throttle body injection, go to step 2). With engine idling, disconnect injector connectors one at a time and note change in idle speed. If idle speed drop is consistent for all injectors, injectors are normal. If idle speed or quality does not change when a particular injector is disconnected, verify battery voltage to injector connector.
On all models, check for a clicking sound at each injector using a stethoscope during engine idle. If any injector fails to emit typical clicking sound, check wiring between ECU and injector. Also, check injector resistance. Injectors should measure 1.5-2.5 ohms on all models except Civic with Throttle Body Injection (TBI).
Resistance should be .6-1.6 ohms on Civic TBI (standard) main injector, 7-10 ohms on auxiliary injector.
On all models, replace any injector that does not fall within resistance specification.