Circuit/System Verification
WARNING: This page is about a different variant/trim than selected.
NOTE:
- The resistance test must be performed at the Fuel Injector or mis-diagnosis will occur.
- The DMM and test leads must be calibrated to 0 Ω in order to prevent mis-diagnosis.
Verify the resistance of each fuel injector:
Fuel Injector Coil Test
- Ignition ON, verify the scan tool ECT temperature is between 10-32°C (50-90°F).
- If not within the specified range
- Measure and record the resistance of each Q17 Fuel Injector with a DMM.
- Subtract the lowest resistance value from the highest resistance value.
- Verify the difference between the lowest value and the highest value is 3 Ω or less.
- If the difference is greater than 3 Ω
- Add all of the Q17 Fuel Injector resistance values to obtain a total resistance value.
- Divide the total resistance by the number of fuel injectors to obtain an average resistance value.
- Subtract the lowest individual fuel injector resistance value from the average resistance value
- Subtract the average resistance value from the highest individual 11-14 Ω resistance value.
- Replace the Q17 Fuel Injector that displays the greatest difference above or below the average value.
- If within the specified range
- Test for 11-14 Ω between terminal A and terminal B of each Q17 Fuel Injector.
- If not between 11-14 Ω
Replace the Q17 Fuel Injector.
- If between 11-14 Ω
- If not between 11-14 Ω
- Verify infinite resistance between each terminal at the Q17 Fuel Injector and the fuel injector housing/case.
- If less than infinite resistance
Replace the Q17 Fuel Injector
- If infinite resistance
- If less than infinite resistance
- Perform the Fuel Injector Balance Test - Fuel Pressure Test.
Fuel Injector Balance Test - Fuel Pressure Test
- DO NOT perform this test if the engine coolant temperature (ECT) is above 94°C (201°F). Irregular fuel pressure readings may result due to hot soak fuel boiling.
- Verify that adequate fuel is in the fuel tank before proceeding with this diagnostic.
- Before proceeding with this test review the User Manual CH 48027-5 for Safety Information and Instructions.
- Install a CH-48027 pressure gauge. Refer to Fuel Pressure Gauge Installation and Removal .
- Ignition ON, engine OFF.
- The fuel pump relay may need to be commanded ON a few times in order to obtain the highest possible fuel pressure.
- DO NOT start the engine.
- Command the Fuel Pump Enable ON with a scan tool.
- Verify the fuel pressure is 380-520 kPa (55-76 psi) with the fuel pump commanded ON.
- If not between 380-520 kPa (55-76 psi)
Refer to Fuel System Diagnosis (LSA)
- If between 380-520 kPa (55-76 psi)
- If not between 380-520 kPa (55-76 psi)
- Verify the fuel pressure does not decrease greater than 34 kPa (5 psi) within 1 minute.
- If the fuel pressure decreases greater than 34 kPa (5 psi)
Refer to Fuel System Diagnosis (LSA) .
- If the fuel pressure does not decreases greater than 34 kPa (5 psi)
- If the fuel pressure decreases greater than 34 kPa (5 psi)
- Perform the appropriate Fuel Injector Balance Test.
NOTE:
NOTE: