Chrysler RAM TRUCK 2500 1994 Service Manual page 966

• FUEL SYSTEM 14 - 25
F U E L T A N K S
INDEX
page
Fuel Gauge Sending Unit 27
Fuel Pump 27
Fuel Tank Capacities . . . . . . . . . . . . . . . . . . . . . . . 27
Fuel Tank Filler Tube Cap 27
Fuel Tank Pressure Relief/Rollover Valve . 27
page
Fuel Tanks 25
General Information 25
Heat Shields 27
No-Lead Fuel Tank Filler Tube 27
GENERAL INFORMATION
All Dodge trucks pass a full 360 degree rollover
without fuel leakage. To accomplish this, fuel and va­
por flow controls are required for all fuel tank con­
nections.
All models have a pressure relief/rollover valve
mounted i n the top of the fuel tank. I n addition to
the valve, improved flow control is used i n the fuel
pump. Fuel flow is controlled i f pump is subjected to
higher than normal pressure during rollover. For the
same reason, a fuel tank filler tube cap (gas cap)
with higher pressure setting is used to control fuel
flow on vehicles with side fill.
An evaporation control system is used to reduce
emissions of fuel vapors into atmosphere by evapora­
tion and to reduce unburned hydrocarbons emitted
by vehicle engine. When the fuel evaporates from
fuel tank, vapors pass through vent hoses or tubes to
a charcoal canister. The are temporarily held i n the
canister. When the engine is running, the vapors are
drawn into intake manifold. Refer to Group 25, Emis­
sion Control System for additional information.
Inspect all hose connections to make sure they are
secure and not leaking. Fuel tank hoses, tubes and
lines should be replaced immediately i f there is any
evidence of degradation that could result i n failure.
Avoid contact with clamps or other components
that cause abrasions or scuffing. Be sure that the
rubber hoses are properly routed to prevent pinching
and to avoid heat sources.
The hoses used on fuel injected vehicles are of a
special construction due to higher fuel pressures in­
volved i n system. I f hoses need replacement, only use
hoses marked EFM/EFI.
The hose clamps used on fuel injected vehicles have
a special rolled edge construction. This prevents the
edge of the clamp from cutting into the hose. Only
these rolled edge type clamps may be used on this
system. Other clamps may cut into the hoses. This
could cause high- pressure fuel leaks. Refer to Fuel
Tubes/Lines/Hoses and Clamps i n this group for ad­
ditional information. Also refer to Quick-Connect Fit­
tings i n this group.
FUEL TANKS
DRAINING FUEL TANK
(1) Remove fuel tank filler tube cap to release fuel
tank pressure.
(2) Perform Fuel System Pressure Release proce­
dure as described i n this group.
(3) Raise vehicle on hoist.
(4) While working over the left rear tire/wheel, dis­
connect the rubber fuel fill hose and clamp at fuel
tank (Fig. 1). Position fuel siphoning/drain hose into
this opening at tank.
FUEL
P U M P
MODULE,
VENT TUBE
AND HOSE
FUEL TANK
FILLER TUBE
CAP
FUEL FILL
TUBE AND HOSE
DRIVER' S SIDE
Of VEHJCLf
CLAMPS (4)
J9414-36
Fig. 1 Fuel Tank Fill and Vent Hoses
(5) Drain fuel into an approved portable holding
tank or a properly labeled gasoline safety container.
TANK REMOVAL
(1) Disconnect negative battery cable at battery.
(2) Remove fuel tank filler tube cap.