Hisun HS700UTV-4, Maintenance Handbook

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ENGINE MANAGEMENT SYSTEM
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5 ． Plugging
Fuel deposits cause plugging resulting in flow shifts over the life of the injector. Fuel varnish or
gumming, a type of injector deposit, is created when certain types of fuel are heated by high
injector tip temperatures at soak (no fuel flow). Deposit build up in the director holes causes
the flow shifts
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Plugging can cause flow restrictions, frictional changes and the collection of other particles
attracted by the tacky surface. The flow restrictions can degrade emissions and drivability.
•
Other fuel and environmental conditions may cause crystal or corrosion growth in the
injector and cause a flow shift.
•
Oxidation stability of the gasoline affects the potential for deposit formation and must be
controlled by the fuel supplier.
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Increased levels of detergent additives reduce the rate of injector plugging.
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Incase of plugging of injector follow the injector cleaning procedure mentioned in the section
below
6 ． Cleaning Procedure
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Electrically disable the fuel pump by removing the fuel pump connection.
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Relieve the fuel pressure in the system and disconnect the fuel connection at the injector.
Plug the fuel feed line.
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Injector cleaner with the specific ratio of the cleaner and gasoline to be mixed in the Injector
cleaning tank.
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Connect the injector-cleaning tank to injector in the vehicle.
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Pressurize the injector-cleaning tank to system pressure.
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Start and idle the engine for 15- 20 minutes.
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Disconnect the injector-cleaning tank from the system and install the fuel pump connections.
Connect the fuel feed line to injector.
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Start and idle the vehicle for an additional 2 minutes to ensure the residual injector cleaner
is flushed from system.
Throttle Body Assembly(with stepper motor)
1
．
Description and Working Principle
The Throttle Body Assembly is an interactive system comprised of the following
subsystems: the main casting body, bearing system, shaft and valve system, return spring
system, cable interface system, throttle position sensing system, and the bypass air control
system. The subsystems interact and support each other to provide all the functional
requirements, which are mentioned below -
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Control intake air flow
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Control idle air flow
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Sense throttle position - Provide position feedback to Engine Controller
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Provide reactionary force to the throttle