Step by step guide on how to test an automotive engine fuel injector, this information
pertains to electronic fuel injected vehicles, not direct injection.
A fuel injector has two main sections, the electrical portion which activates
the valve assembly and allows fuel to enter the engine. This guide will check both
aspects along with the trigger and power circuits supplied by the computer.
Difficulty Scale: 4 of 10
Begin with the vehicle on level ground with the engine off and the parking brake
set. Fuel maybe present during these tests, usual fire precautions are necessary.
Use protective gloves and eye wear for safety.
Step 1 - Start the engine and allow to idle, using
a long metal rod like a screwdriver touch the end of the rod to the injector, gently
lay an ear to the opposite end of the rod or handle to observe an audible clicking
sound, repeat this procedure across all injectors, this can help pinpoint the failing
injector. (Note: This sometimes can be difficult because of internal engine noise.)