Dodge ram truck 3500 1996 Service Manual page 1241

B R FUEL SYSTEM 14 - 7
DIAGNOSIS a n d TESTING (Continued)
Fig, 7 Fuel Pressure Test Port—3.9U5.2U5.9L
. Engines—Typicai
(2) Start the engine and note pressure gauge read­
ing. Fuel pressure should be 339 kPa ± 34 kPa (49.2
psi ± 5 psi) at idle.
(3) I f pressure is at O psi, connect DRB scan tool
and refer to operating instructions in the appropriate
Powertrain Diagnostics Procedures service manual.
(4) I f operating pressure is above 54.2 psi, fuel
pump is OK but fuel pressure regulator is defective.
Fuel, pressure regulator is not serviced separately.
Replace fuel pump module assembly.
FUEL PUMP PRESSURE TEST-ALL ENGINES
WITHOUT PRESSURE TEST PORT
NOTE: The fuel pressure test port is used on cer­
tain engines only. If equipped, the test port will be
located on the fuel rail near the throttle position
sensor (Fig. 7). If not equipped, refer to the follow­
ing procedure: : -
All fuel systems are equipped with a fuel tank
module mounted, combination fuel filter/fuel pressure
regulator. The fuel pressure regulator is not con­
trolled by engine vacuum.
With engine at idle speed, system fuel pressure
should be 339 kPa ± 34 kPa (49.2 psi ± 5 psi).
WARNING: THE F U E L S Y S T E M IS UNDER CON­
STANT F U E L P R E S S U R E EVEN WITH THE ENGINE
OFF. B E F O R E DISCONNECTING F U E L LINE AT
F U E L RAIL, THIS P R E S S U R E MUST B E R E L E A S E D .
R E F E R
TO
THE F U E L S Y S T E M PRESSURE
R E L E A S E P R O C E D U R E .
(1) Release fuel pressure. Refer to the Fuel System
Pressure Release Procedure—-Without Pressure Test
Port.
(2) Disconnect latch clip and fuel line at fuel rail.
Refer to Quick-Connect Fittings for procedures. This
can be found in this section of the group.
(3) Connect adapter tool number 6923 into the fuel
rail (Fig. 8). Be sure adapter tool is fully seated
into fuel rail.
Fig. 8 Installing Adapter Tool and Pressure Gauge
(4) Install latch clip to fuel rail. I f latch clip can
not be fully seated into fuel rail, check for adapter
tool not fully seated to fuel rail.
(5) Connect vehicle fuel line into adapter tool 6923
(Fig. 8). Be sure fuel line is fully seated into adapter
tool 6923.
(6) Remove protective cap at test port "T" on
adapter tool number 6923.
(7) Connect the 0-414 kPa (0-60 psi) fuel pressure
gauge (from gauge set 5069) to the test port "T" (Fig.
8).
(8) Start engine and note pressure gauge reading.
Fuel pressure should be 339 kPa ± 34 kPa (49.2 psi
± 5 psi) at idle.
(9) I f pressure is at 0 psi, connect DRB scan tool
and refer to operating instructions in the appropriate
Powertrain Diagnostics Procedures service manual.
(10) I f operating pressure is above 54.2 psi, fuel
pump is O K but fuel pressure regulator is defective.
Fuel ^ pressure regulator is not serviced separately.
Replace fuel pump module assembly.