*HARD START FUEL SYSTEM
For a complete wiring diagram Refer to Section 8W.
| Possible Causes |
| FUEL CONTAMINATION |
| RESTRICTED FUEL SUPPLY LINE |
| FUEL PUMP INLET STRAINER PLUGGED |
| FUEL PUMP MODULE |
| FAULTY FUEL PUMP MODULE |
| FUEL INJECTOR(S) |
Diagnostic Test
1. CHECKING FUEL PRESSURETurn the ignition off.
WARNING: The fuel system is under a constant pressure (even with the engine off). Before testing or servicing any fuel system hose, fitting or line, the fuel system pressure must be released. Failure to follow these instructions can result in personal injury or death.
Install a fuel pressure gauge at the engine.
Ignition on, engine not running.
With a scan tool, actuate the Fuel Pump and observe the fuel pressure gauge.
NOTE: NOTE: Fuel pressure specification is 407 KPa +/- 34 KPa (59 psi +/- 5 psi).
Choose a conclusion that best matches your fuel pressure reading.
Below Specification
- Go to 2
Within Specification
- Go to 4
2. RESTRICTED FUEL SUPPLY LINE
Turn the ignition off.
WARNING: The fuel system is under a constant pressure (even with the engine off). Before testing or servicing any fuel system hose, fitting or line, the fuel system pressure must be released. Failure to follow these instructions can result in personal injury or death.
Raise vehicle on hoist, and disconnect the fuel supply line at the fuel pump module.
Install special tool #6539 (5/16") #6631(3/8") fuel line adapter and the fuel pressure gauge between the fuel supply line and the fuel pump module.
Ignition on, engine not running.
With the scan tool, actuate the Fuel Pump and observe the fuel pressure gauge.
NOTE: Fuel pressure specification is 407 KPa +/- 34 KPa (59 psi +/- 5 psi).
Is the fuel pressure within specification?
Yes
- Visually and physically inspect the fuel supply lines between the fuel tank and the fuel rail. Repair/replace as necessary.
- Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No
- Go to 3
3. CHECKING THE FUEL PUMP INLET
Turn the ignition off.
WARNING: The fuel system is under a constant pressure (even with the engine off). Before testing or servicing any fuel system hose, fitting or line, the fuel system pressure must be released. Failure to follow these instructions can result in personal injury or death.
Remove the Fuel Pump Module and Fuel Tank Module (if equipped), inspect the Fuel Pump Inlet and the bottom of the fuel tank for debris that could cause the fuel pump inlet to be plugged.
Is the Fuel Inlet Strainer plugged?
Yes
- Repair/Replace as necessary.
- Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No
- Replace the Fuel Pump Module.
- Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE)
4. FUEL PUMP MODULE
NOTE: Before continuing visually and physically inspect the fuel delivery system for external leaks or damage. Repair / replace as necessary.
Turn the ignition off.
WARNING: The fuel system is under a constant pressure (even with the engine off). Before testing or servicing any fuel system hose, fitting or line, the fuel system pressure must be released. Failure to follow these instructions can result in personal injury or death.
Install special tool #6539 (5/16") or #6631 (3/8") fuel line adapter.
Install the fuel pressure gauge.
Start the engine and allow the fuel system to reach maximum pressure.
Turn the ignition off.
NOTE: Fuel specification is 407 KPa +/- 34 KPa (59 psi +/- 5 psi).
Using special tool #C4390, Hose Clamp Pliers, pinch the rubber fuel line between the fuel pressure gauge and the engine.
Monitor the fuel pressure gauge for a minimum of 5 minutes.
NOTE: The pressure should not fall below 241 KPa (35 psi).
Does the fuel pressure drop below 241 KPa (35 psi)?
Yes
- Replace Fuel Pump Module.
- Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No
- Go to 5
5. FUEL INJECTOR(S)
WARNING: The fuel system is under a constant pressure (even with the engine off). Before testing or servicing any fuel system hose, fitting or line, the fuel system pressure must be released. Failure to follow these instructions can result in personal injury or death.
Remove special tool #C4390.
Start the engine and allow the fuel system to reach maximum pressure.
Turn the ignition off.
NOTE: Fuel specification is 407 KPa +/- 34 KPa (59 psi +/- 5 psi).
Using special tool #C4390, Hose Clamp Pliers, pinch the rubber fuel line between the fuel pressure gauge and fuel pump module.
Monitor the fuel pressure gauge for a minimum of 5 minutes.
NOTE: The pressure should not fall below 241 KPa (35 psi)
Does the fuel pressure drop below 241 KPa (35 psi)?
Yes
- Replace the leaking fuel injectors.
- Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No
- Check the fuel for contaminants.
- Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE)