Hard Start Fuel System

HARD START FUEL SYSTEM

For a complete wiring diagram, refer to the Wiring Information.






1. CHECKING FUEL PRESSURE
1. 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 possible serious or fatal injury.

2. Turn the ignition off.
3. Install the Fuel Pressure Decay Tester 8978A on the fuel line near the intake manifold
4. Ignition on, engine not running.
5. With a scan tool, actuate the Fuel Pump and observe the fuel pressure gauge.

NOTE: All gas engines except SRT-4 fuel pressure specification is 407 KPa +/- 34 KPa (59 psi +/- 5 psi). SRT-4 only fuel pressure specification is 552 KPa +/- 34 KPa (80 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

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 possible serious or fatal injury.

1. Turn the ignition off.
2. Remove the Fuel Pressure Decay Tester 8978A.
3. Raise the vehicle on a hoist, and disconnect the fuel supply line at the fuel pump module.
4. Install the Fuel Pressure Decay Tester 8978A at the fuel pump.
5. Ignition on, engine not running.
6. Read the Fuel Pressure Gauge and record the reading. Non SRT-4 fuel pressure specification is 407 KPa +/- 34 KPa (59 psi +/- 5 psi). SRT-4 fuel pressure specification is 552 KPa +/- 34 KPa (80 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. PCM Verification Test.

No

- Go To 3

3. CHECKING THE FUEL PUMP INLET

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 possible serious or fatal injury.

1. Turn the ignition off.
2. 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. PCM Verification Test.

No

- Replace the Fuel Pump Module.
- Perform the PCM Verification Test. PCM Verification Test.

4. FUEL PUMP MODULE

NOTE: Before continuing visually and physically inspect the fuel delivery system for external leaks or damage. Repair / replace as necessary.

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 possible serious or fatal injury.

1. Turn the ignition off.
2. Install the Fuel Pressure Decay Tester 8978A at the intake manifold.
3. Start the engine and allow the fuel system to reach maximum pressure.
4. Turn the ignition off.
5. Close the Fuel System Isolation Valve and then wait five minutes before proceeding.

NOTE: All gas engines except SRT-4 fuel pressure specification is 407 KPa +/- 34 KPa (59 psi +/- 5 psi). SRT-4 only fuel pressure specification is 552 KPa +/- 34 KPa (80 psi +/- 5 psi).

6. Read the Fuel Inlet and Fuel Outlet Pressure Gauges. The pressure should not drop more than 10 psi on either gauge.
7. Monitor the fuel pressure gauge for a minimum of five minutes.

Does the fuel pressure drop more than 10 psi?

Yes - On Fuel Inlet Gauge

- Replace Fuel Pump Module.
- Perform the PCM Verification Test. PCM Verification Test.

Yes - On Fuel Outlet Gauge

- Replace the leaking fuel injector(s).
- Perform the PCM Verification Test. PCM Verification Test.

No

- If directed here by another test, return to that test. Otherwise, test complete.