FUEL LEVEL SENSOR
DESCRIPTION
The fuel gauge level sending unit is attached to the
side of fuel pump module. The level sensor is a vari-
able resistor.
OPERATION
Its resistance changes with the amount of fuel in
the tank. The float arm attached to the sensor moves
as the fuel level changes.
The fuel level input is used as an input for OBD II.
If the fuel level is below 15% of total tank capacity
several monitors are disabled. There are diagnostics
for the level circuit open and shorted.
FUEL TANK
DESCRIPTION
The fuel tank is constructed of a plastic material.
Its main functions are for fuel storage and for place-
ment of the fuel pump module. The tank is made
from High density Polyethylene (HDPE) material.
OPERATION
All models pass a full 360 degree rollover test
without fuel leakage. To accomplish this, fuel and
vapor flow controls are required for all fuel tank con-
nections.
All models are equipped with either one or two
rollover valves mounted into the top of the fuel tank
(or pump module).
An evaporation control system is connected to the
rollover valve(s) to reduce emissions of fuel vapors
into the atmosphere. When fuel evaporates from the
fuel tank, vapors pass through vent hoses or tubes to
a charcoal canister where they are temporarily held.
When the engine is running, the vapors are drawn
into the intake manifold. Certain models are also
equipped with a self-diagnosing system using a Leak
Detection Pump (LDP). Refer to the Emission Control
System for additional information.
FUEL INJECTORS
DESCRIPTION
The injectors are positioned in the cylinder heads
with the nozzle ends directly above the intake valve
port (Fig. 3). The fuel injectors are electrical sole-
noids (Fig. 2).
Fig. 1 Fuel Pump Module—Typical
Fig. 2 Fuel Injector
Fig. 3 Fuel Injector Location—Typical
1 – FUEL INJECTORS
2 – IGNITION COILS
LH FUEL SYSTEM 14 - 3
DESCRIPTION AND OPERATION (Continued)
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