Principal Components; Efi Operation Overview; Initial Priming / Starting Procedure - Polaris 2012 RANGER RZR 570 INTL Service Manual

ELECTRONIC FUEL INJECTION
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 P ump
l
• Fuel Rai
• 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 design
performance with optimum fuel ef ficiency an d lowest
possible em issions. The ig nition a nd inje ction fu nctions
are ele ctronically contr olled, mo nitored an d co ntinually
corrected during operation to maintain peak performance.
The ce ntral comp onent of the system is th e Bosch
Electronic Control Unit (ECU) which manages sys
operation, deter mining th e best co mbination of fuel
mixture a nd ig nition tim ing for the cu rrent op erating
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 f uel back in to th e t ank. At th e
engine, fuel is fed thr ough the fue l ra il an d in to the
injectors, which inject into the intake po rts. Th e ECU
controls the amount of fuel b y 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 n eeded for one
firing of a cylinder is injected during each cycle. When the
intake valve opens, the fuel/air mixture is drawn into the
combustion chamber, ignited and burned.
4.10
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9923523 - 2012 RANGER RZR 570 Service Manual
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The ECU con trols the amount of fuel being injected and
the ig nition timing by m onitoring the primary sensor
signals for int ake air temperature, mani fold absol ute
pressure (load), engine temperature, speed (RPM), and
throttle position. These primary signals are compared to
the programming in the ECU comp uter chip, and the ECU
adjusts the fuel delivery and ignition timing to match the
values.
During operation, the EC U ha s the ability to re-adjus t
temporarily; providing compensation for chan ges 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, acceler ation, e tc., a
automatically calculated by the ECU.

Initial Priming / Starting Procedure

NOTE: The in jection system must be purg ed of all
air prior t o the initial st art 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
waiting for app roximately 3 secon ds at ea ch "ON"
cycle to allow the fuel pump to cycle and shut down.
2. Once step 1 is c ompleted, t urn the key sw itch to
"START" un til the en gine starts or 5 seconds h as
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 s tart, a problem may still exist, and
tem
should be diagnosed.
NOTE: Accurate te sting of EF
recommended utilizing t
Diagnostic Software (dealer only).
richer air / fue l ratio is
"OFF" to " ON" 6 time s,
I c omponents is
he Digit al Wrench™