Electronic Fuel Injection; Principal Components; Efi Operation Overview; Initial Priming / Starting Procedure - Polaris 2014 Sportsman 570 EF Service Manual

FUEL SYSTEM - GENERAL

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
• Fuel Rail
• Fuel Line
• Fuel Filter(s)
• Fuel Injector
• Pressure Regulators
• Throttle Body / lntake Manifold
• Engine Control Unit (ECU)
• Ignition Coils
• Engine Coolant Temperature Sensor (ECT)
• Throttle Position Sensor (TPS)
• Crankshaft Position Sensor (CPS)
• Temperature and Manifold Absolute Pressure
Sensor (T-MAP)
• Idle Air Control Motor (IAC)
• Wire Harness Assembly
• Check Engine Light

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
performance.
The central component of the system is the Bosch
Electronic 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, to the fuel rail. The in-tank
fuel pressure regulator maintains a system operating
pressure and returns any excess fuel back into 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 range can vary
depending on fuel requirements. The controlled injection
of the fuel occurs every other crankshaft revolution, or
once for each 4-stroke cycle. The total amount of fuel
needed for one firing of a cylinder is injected during each
4.10
to maintain peak
9924871 R03 - 2014 Polaris Sportsman® 570 EFI Service Manual
© Copyright 2013 Polaris Sales Inc.
cycle. 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 intake air temperature, manifold absolute
pressure (load), engine temperature, speed (RPM), and
throttle position. 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
Diagnostic Software (dealer only).
the Digital Wrench