Fuel Injectors; Fuel Injector Service - Polaris 2013 RANGER RZR S Service Manual

FUEL INJECTORS

Operation Overview
NOTE: All EFI units utilize quick connect fuel lines.
The fuel injectors mount into the cylinder head, and the
fuel rail attaches to them at the top end. O-rings on both
ends of the injector prevent external fuel leaks and also
insulate it from heat and vibration.
Fuel Rail
When the key switch is on, the fuel rail is pressurized, and
the EFI relay provides voltage to the injectors. During
engine operation, the ECU completes the ground circuit,
energizing the injectors. The valve needle in the injector is
opened electromagnetically, and the pressure in the fuel
rail forces fuel down through the inside. The "director
plate" at the tip of the injector contains a series of
calibrated openings which directs the fuel into the intake
port in a cone-shaped spray pattern.
The amount of fuel injected is controlled by the ECU and
determined by the length of time the valve needle is held
open, also referred to as the "injection duration" or "pulse
width". It may vary in length depending on the speed and
load requirements of the engine.
The ECU gathers fuel injection timing information from the
Crankshaft Position Sensor and Camshaft Phase Sensor
to allow for sequential fuel injection.
Fuel
Injectors
9924125 - 2013 RANGER RZR / RZR S / RZR 4 Service Manual
© Copyright 2012 Polaris Sales Inc.
ELECTRONIC FUEL INJECTION

Fuel Injector Service

Injector problems typically fall into three general
categories- electrical, dirty / clogged, or leakage. An
electrical problem usually causes one or both of the
injectors to stop functioning. Several methods may be
used to check if the injectors are operating.
• With the engine running at idle, feel for operational
vibration, indicating that they are opening and
closing.
• When temperatures prohibit touching, listen for a
buzzing or clicking sound with a screwdriver or
mechanic's stethoscope.
• Disconnect the electrical connector from an
injector and listen for a change in idle performance
(only running on one cylinder) or a change in
injector noise or vibration.
NOTE: Do not apply voltage directly to the fuel
injector(s). Excessive voltage will burn out the
injector(s). Do not ground the injector(s) with the
ignition on. lnjector(s) will open/turn on if relay is
energized.
If an injector is not operating, it can indicate either a bad
injector, or a wiring/electrical connection problem. Check
as follows:
Injector leakage is very unlikely, but in rare instances it can
be internal (past the tip of the valve needle), or external
(weeping around the injector body). The loss of system
pressure from the leakage can cause hot restart problems
and longer cranking times.
Injector problems due to dirt or clogging are unlikely due
to the design of the injectors, the high fuel pressure, the
use of filters and the detergent additives in the gasoline.
Symptoms that could be caused by dirty/clogged injectors
include rough idle, hesitation/stumble during acceleration,
or triggering of fault codes related to fuel delivery. Injector
clogging is usually caused by a buildup of deposits on the
director plate, restricting the flow of fuel, resulting in a poor
spray pattern. Some contributing factors to injector
clogging include; dirty air filters, higher than normal
operating temperatures, short operating intervals and
dirty, incorrect, or poor quality fuel. Cleaning of clogged
injectors is not recommended; they should be replaced.
Additives and higher grades of fuel can be used as a
preventative measure if clogging has been a problem.
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