Visual Inspection

A visual inspection should be made before attempting to diagnose or service the diesel fuel injection system. A visual check will help find these conditions. It also saves unnecessary test and diagnostic time. A thorough visual inspection of the fuel injection system includes the following checks:

1. Verify pigtail electrical connector from water- in-fuel (WIF) sensor is firmly attached to main engine wiring harness. The WIF sensor is located on side of Fuel Filter/Water Separator canister. Inspect connector for corrosion or damaged wires.
2. Check for water in fuel filter/water separator. A water drain is supplied on the filter/separator. Refer to Fuel Filter/Water Separator Removal/Installation for water draining operation.
3. Verify fuel filter has been serviced according to Maintenance Schedules.
4. Verify pre-filter (within fuel heater) has been cleaned when fuel filter was serviced.






5. Inspect air cleaner element (filter) for restrictions by using the built-on Filter Minder (TM). Do not remove the top of air cleaner housing to inspect condition of air cleaner element. Refer to Air Cleaner Housing/Air Cleaner Element for information.
6. Check front of turbocharger intercooler for restrictions to airflow (insects, debris etc.). Clean if necessary.
7. Be sure turbocharger output hose is firmly connected to charge air cooler (intercooler) inlet tube. Verify charge air cooler output hose is firmly connected to cooler and intake manifold.
8. Verify turbocharger wastegate adjustment is correct. Refer to Exhaust System and Intake Manifold for procedures.
9. Verify throttle linkage is "breaking over". Refer to Throttle Linkage Adjustment-Diesel Engine for procedures.
10. Verify correct throttle linkage adjustment. Refer to Throttle Linkage Adjustment-Diesel Engine for procedures.
11. Verify correct Throttle Position Sensor (TPS) output voltage. Refer to Throttle Position Sensor Removal/Installation/Testing/Adjustment.
12. Be sure battery connections (on both batteries) are tight and not corroded.






13. Be sure three 32-way connectors are fully engaged into the powertrain control module (PCM).






14. Verify electrical connector is firmly connected to fuel shutdown solenoid on the injection pump. Inspect connector for corrosion or damage.
15. Verify electrical connector is firmly connected to intake manifold air temperature sensor. Inspect connector for corrosion or damaged wires. The sensor is located on top of intake manifold.






16. Be sure electrical connections at intake manifold air heater relays are tight and not corroded.






17. Be sure intake manifold air heater electrical cable connections at intake manifold are tight and free of corrosion.
18. Inspect all fuel supply and return lines for signs of damage or kinking.
19. Inspect all fuel supply and return lines for signs of leakage.
20. Inspect throttle linkage and accelerator linkage for binding.
21. Be sure throttle return spring is connected.
22. Be sure ground connections are tight and free of corrosion.
23. Be sure accessory' drive belt is not damaged or slipping.
24. Automatic Transmission Only: Be sure electrical connectors are firmly connected to plugs on transmission case.
25. Inspect starter motor and starter solenoid connections for tightness and corrosion.