4-2
Chapter 4 Fuel and exhaust systems
2.3 The fuel pump module electrical connector is located in the
trunk, under the mat near the base of the left shock tower
3.4 On four-cylinder engines, connect a fuel pressure gauge to
the fuel rail at the test port
2
Fuel pressure relief procedure
Refer to illustration 2.3
Warning: Gasoline is extremely flammable,
so take extra precautions when you work on
any part of the fuel system. Don't smoke or
allow open flames or bare light bulbs near the
work area, and don't work in a garage where
a natural gas-type appliance (such as a water
heater or a clothes dryer) with a pilot light is
present. Since gasoline is carcinogenic, wear
latex gloves when there's a possibility of
being exposed to fuel, and if you spill any on
your skin, rinse it off immediately with soap
and water. Mop up any spills immediately and
do not store fuel-soaked rags where they
could ignite. The fuel system is under con-
stant pressure, so, if any fuel lines are to be
disconnected, the pressure must be relieved
first. When you perform any kind of work on
the fuel system, wear safety glasses and have
a Class B type fire extinguisher on hand.
1
Remove the fuel filler cap to relieve the
fuel tank pressure.
2
Working inside the trunk, fold back the
trunk mat near the base of the left shock
tower.
3
Locate the fuel pump electrical connec-
tor and disconnect it from the wiring harness
(see illustration).
4
Next, start the engine and allow it to run
until it stops. This should only take a few sec-
onds. Crank the engine again, to ensure the
fuel pressure is completely relieved. Before
working on any part of the fuel system, dis-
connect the negative battery cable from the
ground stud on the left shock tower (see
Chapter 5, Section 1).
5
Even after the fuel pressure has been
relieved, always lay a shop towel over any
fuel connection that is to be separated to
absorb the residual fuel that will leak out.
6
When you are finished working on the
fuel system, reconnect fuel pump electrical
connector to the wiring harness. Turn the
ignition key to the ON position a few times to
pressurize the system and check the serviced
area for leaks.
7
Install the fuel filler cap and tighten it
securely. Note: If the fuel filler cap seal allows
the fuel tank pressure to escape because of a
damaged seal or it has not been tightened
sufficiently, the CHECK ENGINE light will illu-
minate on the instrument panel.
3
Fuel pump/fuel pressure
regulator - check
Warning: Gasoline is extremely flammable,
so take extra precautions when you work on
any part of the fuel system (see the Warning
in Section 2).
Note 1: These vehicles are equipped with a
"returnless" fuel system in which the fuel
pressure regulator is part of the fuel pump
module and located inside the fuel tank.
Note 2: The fuel pump will operate as long as
the engine is cranking or running and the
PCM is receiving ignition reference pulses
from the electronic ignition system. If there
are no reference pulses, the fuel pump will
shut off after approximately 1 second.
Note 3: To perform the fuel pressure check,
you will need to obtain a fuel pressure gauge
and adapter set (fuel line fittings). On V6
engines, the fuel supply line is not equipped
with a fuel pressure test port (Schrader valve
fitting). A special fuel pressure test adapter
(factory tool No. 6539 or equivalent) must be
installed between the fuel supply line and the
fuel rail.
Preliminary check
Note: On all models, the fuel pump is located
inside the fuel tank (see Section 7).
1
If you suspect insufficient fuel delivery,
first inspect all fuel lines to ensure that the
problem is not simply a leak in a line.
2
Set the parking brake and remove the
fuel filler cap. Have an assistant turn the igni-
tion switch to the ON position while you listen
at the fuel filler neck opening. You should
hear a "whirring" sound, lasting for a couple
of seconds. Start the engine. The whirring
sound should now be continuous (although
harder to hear with the engine running). If
there is no sound, either the fuel pump fuses,
fuel pump, fuel pump relay, automatic shut-
down (ASD) relay or related circuits are
defective (proceed to Step 15).
System pressure check
Refer to illustrations 3.4 and 3.5
3
Perform the fuel pressure relief proce-
dure (see Section 2).
4
On four-cylinder engines, remove the
cap from the fuel pressure test port (Schrader
valve fitting) on the fuel rail and attach a fuel
pressure gauge (see illustration).
5
On V6 engines, the fuel supply line is not
equipped with a fuel pressure test port
(Schrader valve fitting). A special fuel pres-
sure test adapter (factory tool No. 6539 or
equivalent) must be installed between the fuel
supply line and the fuel rail. Disconnect the
fuel supply line from the fuel rail (see Sec-
tion 4) and install the fuel pressure test
adapter between the supply line and the fuel
rail (see illustration). Attach a fuel pressure
gauge to the test adapter fitting.
6
Start the engine and observe the pres-
sure reading on the gauge. Compare it with
the pressure listed in this Chapter's Specifi-
cations.
7
If the fuel pressure is higher than speci-
fied, check for a kinked or restricted fuel line
between the fuel filter and fuel pump module.
If the line is OK, replace the fuel pressure reg-
ulator (see Section 14).
8
If the fuel pressure is lower than speci-
fied, replace the fuel filter (see Section 15)
and perform the pressure check again. If it's
still low, remove the fuel pump module (see
Section 7) and inspect the fuel inlet strainer
for obstructions. If it's clogged, replace the
strainer. If the strainer is OK, replace the fuel
pump.
9
If there is no fuel pressure, check the
fuel pump, ASD and fuel pump relays as out-
li ned below.
10
Next, verify that the system holds pres-
sure. Note the fuel pressure with the engine