Fuel Injector Balance Test

NOTE: Make sure injectors have been cleaned with an approved cleaner prior to testing. Fuel Injector Cleaning Procedure
The injector balance test is done to verify a balanced distribution of fuel to all cylinders.
1. Start by hooking up a fuel pressure gauge at the schrader valve or inline before the fuel pressure regulator (refer to gauge manufacturer instructions).
2. Pressurize the fuel system to operating pressure of approximately 330 kPa (48 psi). Fuel System Pressurizing Procedure
^ If pressure is not approximately 330 kPa (48 psi) diagnose and repair the problem before proceeding.
3. Remove injector harness connector and connect an injector pulse tester.
4. Pulse one injector at a time. Allow pressure to rise and stabilize in between each injector tested.
NOTE: The time each injector is pulsed is very important. Each injector should be pulsed at the same time interval, (example: 1 ms each).
5. The rate of drop should be even across all the injectors. All pressure drops should be within 3% of each other, if not replace injector.
6. If there is no pressure drop when injector is pulsed, verify there is a good connection between the injector and pulse tester. If connection is good, a check of the injector circuit is required.
7. First, check the resistance of the injector, if resistance is OK verify there is power to injector by connecting the injector harness connector and START engine.
8. Use a "NOID" light to check for pulses (light should flash).
^ If light does not flash this is an indication of a problem in the injector to SBEC circuit. Fuel Injector Electrical Circuit Diagnosis
^ If light flashes, recheck pressure drop to verify malfunction.
NOTE: It may not be possible to connect a noid light to the harness while connected to injector. If this is the case disconnect harness and connect noid light to harness and check pulses.