Visual Inspection

A visual inspection for loose, disconnected, or incorrectly routed wires and hoses 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. Be sure that the battery connections (on both batteries) are tight and not corroded.

PCM Location:

2. Be sure that the 60-way connector is fully engaged with the Powertrain Control Module (PCM). Verify that the connector mounting screw is tight.

Intake Manifold Air Heater Relays:

3. Be sure that the electrical connections at the intake manifold air heater relays are tight and not corroded.
4. Inspect the starter motor and starter solenoid connections for tightness and corrosion.

Electronic Components:

5. Verify that the electrical connector is firmly connected to the intake manifold air temperature sensor. Inspect the connector for corrosion or damaged wires. The sensor is located on the top of the intake manifold.

Water-in-fuel Sensor:

6. Verify that the water-in-fuel (WIF) sensor electrical connector is firmly attached to the sensor. Inspect the connector for corrosion or damaged wires.
7. Check for water in the fuel filter/water separator. A water drain is supplied on the filter/separator. Refer to Fuel Filter/Water Separator for water draining procedure.

Electronic Components:

8. Verify that the electrical connector is firmly connected to the fuel shutdown solenoid on the injection pump. Inspect the connector for corrosion or damage.

Air Heater:

9. Be sure that the intake manifold air heater electrical cable connections at the intake manifold are tight and free of corrosion.
10. Inspect the throttle linkage and accelerator linkage for binding.
11. Be sure that the throttle return spring is connected.
12. Inspect all fuel supply and return lines for signs of leakage.
13. Be sure that the ground connections are tight and free of corrosion.
14. Inspect the air cleaner element for restrictions by using the built-on Filter Minder. Do not remove the top of air cleaner housing to inspect condition of air filter. Refer to Air Filter/Filter Housing for Filter Minder information.
15. Be sure that the turbocharger output hose is connected to the charge air cooler (intercooler) inlet tube. Verify that the charge air cooler output hose is connected to the cooler and the intake manifold.
16. Be sure that the vacuum pump-to-brake booster hose is connected and not damaged.
17. Be sure that the accessory drive belt is not damaged or slipping.

Transmission Temperature Sensor:

18. Automatic Transmission Only: Raise the vehicle and check the electrical connection at the transmission temperature sensor.
19. Automatic Transmission Only: Be sure the electrical connector is firmly connected to the plug leading to the overdrive solenoid in the transmission.