Checking Hard Start (Fuel System)

CHECKING HARD START (FUEL SYSTEM)






POSSIBLE CAUSES
RESTRICTED FUEL SUPPLY LINE
FUEL PUMP INLET STRAINER PLUGGED
FUEL PUMP MODULE
FAULTY FUEL PUMP MODULE
FUEL INJECTOR(S)
FUEL CONTAMINATION

Diagnostic Test
1. CHECKING FUEL PRESSURE





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.

Turn the ignition off.
Install a fuel pressure gauge at the engine. Turn the ignition on.
With the DRB III, actuate the Fuel Pump and observe the fuel pressure gauge.

Note: Fuel pressure specification is 3.7 to 4.2 bar (54 to 61 psi).

Choose a conclusion that best matches your fuel pressure reading.
Below Specification
Go To 2
Within Specification
Go To 4

2. RESTRICTED FUEL FILTER

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.

Turn the ignition off.
Remove the Fuel Filter and inspect for a plugged filter.
Is the fuel filter plugged?
Yes>> Replace the Fuel Filter.
Perform Powertrain Verification Test - Ver 1
No>> Go To 3

3. CHECKING FUEL STRAINER

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.

With the ignition off.
Remove and inspect the Fuel Strainer.
Is the Fuel Strainer plugged?
Yes>> Replace the Fuel Strainer.
Perform Powertrain Verification Test - Ver 1
No>> Replace the Fuel Pump.
Perform Powertrain Verification Test - Ver 1

4. 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.

Start the engine and allow the fuel system to reach maximum pressure.
Turn the ignition off.

Note: Fuel pressure specification is 3.7 to 4.2 bar (54 to 61 psi).

Apply special tool #C-4390, Hose Clamp Pliers, between the fuel pressure gauge and the fuel pump.
Monitor the fuel pressure gauge for a minimum of 5 minutes.

Note: The pressure should not fall below 3.0 bar (44 psi).

Does the fuel pressure drop?
Yes>> Replace the leaking fuel injectors.
Perform Powertrain Verification Test - Ver 1
No>> Check the fuel for contaminants.
Perform Powertrain Verification Test - Ver 1