Polaris A12MH46AX Service Manual page 162

Fuel Injector Service
Injector problems typically fall into three general
categories- electrical, dirty/clogged, or leakage. An
electrical problem usually causes the injector to stop
functioning.
NOTE: Do not apply voltage directly to the fuel
injector(s). Excessive voltage will burn out the
injector(s). Do not ground the injector with the
ignition "on". lnjector 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.
9923412 - 2012 Sportsman 400/500 and EFI Tractor Service Manual
© Copyright 2011 Polaris Sales Inc.
500 EFI FUEL SYSTEM
Fuel Injector Resistance Test
If an injector is not operating, it can indicate either a bad
injector, or a wiring/electrical connection problem. Check
as follows:
• Using an ohmmeter, test for continuity by placing
the test leads on each pin of the injector.
• Resistance specification is 12.0
68°F)
Injector Resistance Specification:
 
12.0 ±0.4
Fuel Injector Replacement
1. Engine must be cool. Depressurize fuel system
through test valve in fuel rail.
2. Remove the front fender assembly and fuel tank.
3. Thoroughly clean the area around and including the
throttle body/manifold and the injectors.
4. Disconnect the fuel injector harness.
5. Remove the fuel rail mounting screws, doubler plate
and carefully loosen / pull the rail away from the
injector.
6. Reverse the procedures to install the new injector and
reassemble. Use new O-rings any time an injector is
removed (new replacement injectors include new O-
rings). Lubricate the upper O-ring lightly with soapy
water to aid installation. The lower O-ring should
remain dry. Torque the fuel rail mounting screws to
5~7 ft. lbs. (6-9 Nm). Then install the doubler plate
and torque to 8~9.5 ft. lbs. (11-13 Nm).
Fuel Rail Mounting Screws:
5~7 ft. lbs. (6-9 Nm)
Doubler Plate Screws
8~9.5 ft. lbs. (11-13 Nm)
±0.4 (20°C,
W W
(20°C, 68°F)
= T
4.47
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