Operation - Fuel Injector; Removal; Installation; Fuel Pump Relay Description - Chrysler Vehicle User Manual

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FUEL INJECTOR (Continued)

OPERATION - FUEL INJECTOR

The top (fuel entry) end of the injector (Fig. 10) is
attached into an opening on the fuel rail.
The fuel injectors are electrical solenoids. The
injector contains a pintle that closes off an orifice at
the nozzle end. When electric current is supplied to
the injector, the armature and needle move a short
distance against a spring, allowing fuel to flow out
the orifice. Because the fuel is under high pressure, a
fine spray is developed in the shape of a pencil
stream. The spraying action atomizes the fuel, add-
ing it to the air entering the combustion chamber.
The nozzle (outlet) ends of the injectors are posi-
tioned into openings in the intake manifold just
above the intake valve ports of the cylinder head.
The engine wiring harness connector for each fuel
injector is equipped with an attached numerical tag
(INJ 1, INJ 2 etc.). This is used to identify each fuel
injector.
The injectors are energized individually in a
sequential order by the powertrain control module
(PCM). The PCM will adjust injector pulse width by
switching the ground path to each individual injector
on and off. Injector pulse width is the period of time
that the injector is energized. The PCM will adjust
injector pulse width based on various inputs it
receives.
Battery voltage is supplied to the injectors through
the ASD relay.
The PCM determines injector pulse width based on
various inputs.

REMOVAL

(1) Remove fuel rail. Refer to Fuel Injector Rail
Removal in this section.
(2) Disconnect clip(s) that retain fuel injector(s) to
fuel rail (Fig. 11).

INSTALLATION

(1) Install fuel injector(s) into fuel rail assembly
and install retaining clip(s).
(2) If same injector(s) is being reinstalled, install
new o-ring(s).
(3) Apply a small amount of clean engine oil to
each injector o-ring. This will aid in installation.
(4) Install fuel rail. Refer to Fuel Rail Installation.
(5) Start engine and check for fuel leaks.
Fig. 11 FUEL INJECTOR MOUNTING
1 - INLET FITTING
2 - FUEL INJECTOR RAIL
3 - CLIP
4 - FUEL INJECTOR
FUEL PUMP RELAY
DESCRIPTION
The 5–pin, 12–volt, fuel pump relay is located in
the Power Distribution Center (PDC). Refer to the
label on the PDC cover for relay location.

OPERATION

The Powertrain Control Module (PCM) energizes
the electric fuel pump through the fuel pump relay.
The fuel pump relay is energized by first applying
battery voltage to it when the ignition key is turned
ON, and then applying a ground signal to the relay
from the PCM.
Whenever the ignition key is turned ON, the elec-
tric fuel pump will operate. But, the PCM will shut-
down the ground circuit to the fuel pump relay in
approximately 1–3 seconds unless the engine is oper-
ating or the starter motor is engaged.
REMOVAL
The fuel pump relay is located in the Power Distri-
bution Center (PDC) (Fig. 12). Refer to label on PDC
cover for relay location.
(1) Remove PDC cover.
(2) Remove relay from PDC.
FUEL INJECTION 14 - 27