Important Notes - Kohler ECV940 Service Manual

EFI SYSTEM-ELECTRONIC THROTTLE BODY (ETB)
High pressure fuel line is an assembly of hoses, injector
caps and a fuel connector to fuel pump module. High
pressure fuel line feeds fuel to top of injectors through
injector caps. Caps are fastened to intake manifold and
injectors are locked into place. A small retaining clip
provides a secondary lock.
High pressure fuel line is serviced as a complete
assembly to prevent tampering and safety hazards.
Components are not individually serviceable.
Vent hose assembly is intended to vent fuel vapor out of
fuel pump module and direct fuel vapor into electronic
throttle body. Most EFI engines are equipped with an
engine mounted purge port on #2 cylinder barrel baffl e.
This capped purge port can be used by OEM to vent fuel
tanks or used in conjunction with a carbon canister kit for
evaporative emissions compliance. Purge port connects
to vent hose assembly and directs all fuel vapor into
electronic throttle body. If purge port remains unused,
port must remain capped to prevent dirt from entering
engine.
EFI engines have no carburetor, so throttle function
(regulate incoming combustion airfl ow) is achieved with
a throttle valve in a separate electronic throttle body
(ETB) attached to intake manifold. ETB is an assembly
of three functional components: 1) A mechanical throttle
body to control air fl ow to engine. 2) A DC electric motor
and gear reduction to drive and position throttle blade. 3)
A non-contact throttle position sensor to measure throttle
position. This technology is common on many modern
automobiles, including a return spring feature. Return
spring will mechanically return throttle blade to a home
position if power is lost or interrupted to drive motor.
Home position is above normal low idle position, but
typically is low RPM and very low load.
ETB (Electronic throttle body)/intake manifold provides
mounting for fuel injectors, throttle position sensor,
TMAP sensor, high pressure fuel line, and air cleaner
assembly.
ETB Engine idle speed is not adjustable and is preset
and controlled by ECU. Standard idle speed setting for
EFI engines is 1500 RPM, but certain applications might
require a diff erent setting.
For starting and warm up, ECU will adjust fuel and
ignition timing, based upon ambient temperature, engine
temperature, and loads present. In cold conditions, idle
speed will be diff erent than normal for a few moments.
Idle speed typically starts higher than normal, but
gradually decreases to established setting as operation
continues. Engine must be completely warmed up, in
closed loop operating mode for accurate idle check.
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IMPORTANT NOTES!

● Cleanliness is essential and must be maintained at all
times when servicing or working on EFI system. Dirt,
even in small quantities, can cause signifi cant
problems.
● Clean any joint or fi tting with parts cleaning solvent
before opening to prevent dirt from entering system.
● Always depressurize fuel system through fuel
connector on fuel pump module before disconnecting
or servicing any fuel system components.
● Never attempt to service any fuel system component
while engine is running or ignition switch is ON.
● Do not use compressed air if system is open. Cover
any parts removed and wrap any open joints with
plastic if they will remain open for any length of time.
New parts should be removed from their protective
packaging just prior to installation.
● Avoid direct water or spray contact with system
components.
● Do not disconnect or reconnect ECU wiring harness
connector or any individual components with ignition
on. This can send a damaging voltage spike through
ECU.
● Do not allow battery cables to touch opposing
terminals. When connecting battery cables attach
positive (+) cable to positive (+) battery terminal fi rst,
followed by negative (-) cable to negative (-) battery
terminal.
● Never start engine when cables are loose or poorly
connected to battery terminals.
● Never disconnect battery while engine is running.
● Never use a quick battery charger to start engine.
● Do not charge battery with key switch ON.
● Always disconnect negative (-) battery cable before
charging battery, and also unplug harness from ECU
before performing any welding on equipment.
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