Electronic Fuel Injection; Principal Components; Efi Operation Overview; Initial Priming / Starting Procedure - Polaris 2007 SPORTSMAN X2 800 Service Manual

ELECTRONIC FUEL INJECTION

Principal Components

The Electronic Fuel Injection (EFI) system is a complete engine
fuel and ignition management design. This system includes the
following principal components:
• Fuel Pump
l
• Fuel Rai
• Fuel Line(s)
• Fuel Filter(s)
• Fuel Injectors
• Pressure Regulator
• Throttle Body / lntake Manifold
• Engine Control Unit (ECU)
• Ignition Coils
• Coolant Temperature Sensor
• Throttle Position Sensor (TPS)
• Crankshaft Position Sensor (CPS)
• Intake Air Temperature and Barometric Air
Pressure Sensor (T-BAP)
• Wire Harness Assembly
• Check Engine Light (MIL)

EFI Operation Overview

The EFI system is designed to provide peak engine performance
with optimum fuel efficiency and lowest possible emissions.
The ignition and injection functions are electronically
controlled, monitored and continually corrected during
operation to maintain peak performance.
The central component of the system is the Bosch Engine
Control Unit (ECU) which manages system operation,
determining the best combination of fuel mixture and ignition
timing for the current operating conditions.
An in-tank electric fuel pump is used to move fuel from the tank
through the fuel line and in-line fuel filter. The in-tank fuel
pressure regulator maintains a system operating pressure of 39
psi and returns any excess fuel to the tank. At the engine, fuel is
fed through the fuel rail and into the injectors, which inject into
the intake ports. The ECU controls the amount of fuel by varying
the length of time that the injectors are "on." This can range from
1.5-8.0 milliseconds depending on fuel requirements. The
controlled injection of the fuel occurs each crankshaft
revolution, or twice for each 4-stroke cycle. One-half the total
amount of fuel needed for one firing of a cylinder is injected
during each injection. When the intake valve opens, the fuel/air
mixture is drawn into the combustion chamber, ignited. and
burned.
The ECU controls the amount of fuel being injected and the
ignition timing by monitoring the primary sensor signals for air
temperature, barometric air pressure, engine temperature, speed
(RPM), and throttle position (load). These primary signals are
compared to the programming in the ECU computer chip, and
the ECU adjusts the fuel delivery and ignition timing to match
the values.
During operation the ECU has the ability to re-adjust
temporarily, providing compensation for changes in overall
engine condition and operating environment, so it will be able
to maintain the ideal air/fuel ratio.
During certain operating periods such as cold starts, warm up,
acceleration, etc., a richer air/fuel ratio is automatically
calculated by the ECU.

Initial Priming / Starting Procedure

NOTE: The Injection system must be purged of all
air prior to the initial start up, and/or any time the
system has been disassembled.
If the EFI system is completely empty of fuel or has been
disassembled and repaired:
1. Cycle the key switch from "OFF" to "ON" 6 times,
waiting for approximately 3 seconds at each "ON" cycle to
allow the fuel pump to cycle and shut down.
2. Once step 1 is completed, turn the key switch to "START"
until the engine starts or 5 seconds has passed.
3. If the engine failed to start, repeat step 1 for 2 more cycles
and attempt to start the engine.
If the engine fails to start, a problem may still exist, and should
be diagnosed.
NOTE: Accurate testing of EFI components is
recommended utilizing
Software (dealer only).
FUEL INJECTION
the Polaris Diagnostic
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