Operation Overview; Initial Priming / Starting Procedure - Polaris Sportsman XP 1000 S 2020 Service Manual

ENGINE ELECTRICAL

OPERATION OVERVIEW

The Electronic Fuel Injection (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
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 of 58 PSI (400 kPa). 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 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
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.
4.4
INITIAL PRIMING / STARTING
PROCEDURE
NOTICE
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 Electronic Fuel Injection (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 still exists and
should be diagnosed.
NOTICE
Accurate testing of EFI components is recommended
utilizing the Digital Wrench® Diagnostic Software
(dealer only).
9931493 R03 - 2020-2021 Sportsman XP 1000 S Service Manual
© Copyright Polaris Inc.