TEST
ACTION
APPLICABILITY
5
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.
Install a fuel pressure gauge.
Start the engine and observe the fuel pressure reading.
NOTE: Fuel pressure specification is 400 KPa +/- 34 KPa (58 psi +/- 5 psi).
Choose a conclusion that best matches your fuel pressure reading.
All
Within Specification
Go To
6
Below Specification
Go To
12
Above Specification
Replace the fuel filter/pressure regulator.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
6
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.
Install special 5/16 fuel line adapter tool #6539.
Attach a fuel pressure test gauge to the T fitting on the tool #6539
Start the engine and allow the fuel system to reach maximum pressure.
Turn the ignition off.
NOTE: Fuel specification is 400 KPa +/- 34 KPa (58 psi +/- 5 psi).
Using special tool #C4390, Hose Clamp Pliers, slowly clamp off the rubber hose on
the Fuel Pressure adapter between the fuel pressure gauge and the 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 gauge fall below the above specification?
All
Yes
→ Replace the leaking Injector(s).
Perform POWERTRAIN VERIFICATION TEST VER - 5.
No
→ Go To 7
7
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.
CAUTION: After each actuation of the Fuel Injector, start the engine to clear
the cylinder of fuel. Failure to do so could cause engine damage.
Install a Fuel Pressure Gauge to the fuel rail.
Start the engine and allow the fuel pressure to reach maximum pressure.
Turn the engine off, leaving the ignition on.
Using the DRBIII
t, actuate the Fuel Injector for the cylinder that indicated the
misfire.
Monitor the fuel pressure gauge.
Does the fuel pressure gauge indicate a drop in fuel pressure?
All
Yes
→ Go To 8
No
→ Go To 9
125
DRIVEABILITY - NGC
P0300-MULTIPLE CYLINDER MISFIRE —
Continued