Circuit Test A2-7E - Fuel System Diagnosis/Fuel Injector Balance Test
NOTE:
The following test is performed using fuel injector tester(J-39021).
- Connect scan tool to DLC. Observe coolant temperature. If coolant temperature is above 201°F (94°C), allow to cool below specified temperature and go to next step.
- Relieve fuel system pressure. See FUEL SYSTEM PRESSURE RELEASE under FUEL SYSTEM. Install fuel pressure gauge. Connect a fused jumper wire between duty check DLC terminals "Fp" and "+B". Fuel pump should run. Place bleed hose of fuel pressure gauge into container. Bleed air from gauge and observe gauge reading. If fuel pressure is 38-44 psi (2.7-3.1 kg/cm2 ), go to next step. If fuel pressure is not as specified, go to CIRCUIT TEST A2-7B.
- Remove jumper wire. Observe fuel pressure gauge. If fuel pressure stays constant, go to next step. If fuel pressure does not remain constant, go to CIRCUIT TEST A2-7B.
- Connect fuel injector tester to a fuel injector following manufacturer's instructions. Set amperage switch on tester to 0.5-2.5 amp position. Using a fused jumper wire, momentarily connect duty check DLC terminals "Fp" and "+B" to pressurize fuel system. Record fuel pressure after reading stabilizes. Push START button on tester to energize fuel injector. Record fuel pressure. Repeat step for remaining injectors.
- Subtract second pressure reading from first reading to obtain a pressure drop value. Repeat for remaining injectors. Add all pressure drop values and divide by number of injectors to obtain average pressure drop value. If any injector has a pressure drop of 1.5 psi (.11 kg/cm2 ) greater or less than average pressure drop value, go to next step. If pressure drop is not as specified, see TESTS W/O CODES article.
- Retest faulty fuel injector(s). Replace faulty injectors as necessary. Go to ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK in appropriate TESTS W/CODES article. If fuel injector(s) is okay, see TESTS W/O CODES article.