Lpg / Natural Gas Pressure Regulators; Injector Rail And Injectors; Electrical System Checks - Kubota WG1605-E3 Diagnostic Manual

WG1605-G-E3,WG1605-L-E3,WG1605-GL-E3, DM

LPG / NATURAL GAS PRESSURE REGULATORS

LPG / NATURAL GAS DUAL STAGE REGULATOR
(DSR)
The EControls LPG / Natural Gas DSR is a two stage
mechanical regulator with an integral vaporizer which
reduces the fuel inlet or tank pressure to a specific lower
pressure and adds heat to the fuel for vaporization. You
should check the following items at a minimum of once
per year:
• Check for any fuel leaks at the inlet and outlet
fittings.
• Check for any fuel leaks at the connecting seams of
the regulator body.
• Check the inlet and outlet coolant fittings at the
regulator body.
• Check the inlet and outlet coolant lines for
hardening, cracking, chaffing or splits. If any of these
conditions exist replace the coolant lines.
• Check the inlet and outlet coolant line hose clamps
at each connection, tighten if necessary.
• Check the mounting bracket to insure the regulator is
securely mounted, tighten if necessary.
• Check any of the rubber isolators used for mounting
for cracking, hardening or separation.
• Check the regulator for a buildup of oil in the second
stage chamber of the regulator. Drain the oil by
opening the drain plug located at the bottom of the
secondary chamber.
NOTE
• Certain Kubota LPG / Natural Gas systems may
be fitted with a Direct Electronic Pressure
Regulator (DEPR) which is downstream of the
DSR. Check these items when inspecting the
DEPR:
• Check the harness connection on the electronic
control section, to insure it is seated and locked.
• Check to make sure the DEPR assembly is securely
mounted.
NOTE
• All EControls LPG / Natural Gas systems are
fitted with an LPG / Natural Gas Fuel Lock Off
device which is typically mounted to the inlet of
the DSR. These are the additional items when
inspecting the regulator:
• Check for any fuel leaks at the inlet and outlet
fittings.
• Check the Lock Off electrical connector, to insure it
is seated and locked.
• Check to insure the solenoid retaining nut is
tightened and fully seated.
GASOLINE FUEL PRESSURE MANIFOLD
On Bi-fuel and dedicated gasoline engines, fuel is
delivered to the gasoline injector rails via an electric fuel
pump. The ECM controls fuel delivery pressure via a
PWM low side drive circuit connected to the ground
terminal of the pump. The ECM increases or decreases
the fuel pump's voltage to achieve the desired pressure
using pressure feedback information from the gasoline
fuel pressure manifold
assembly also measures the gasoline fuel temperature
and provides this information to the ECM. This manifold,
along with the electric fuel pump, will be located on the
chassis. By closely maintaining the target fuel pressure
using minimum pump current flow, a minimal amount of
fuel is returned to the tank. The fuel pressure manifold
and fuel pump do not require adjustment. The following
items must be inspected once per year.
• Check the mounting bracket for the fuel pressure
manifold and fuel pump, for cracks or breakage.
• Check the securing method for the fuel pressure
manifold and fuel pump to insure the devices are
firmly attached.
• Check the electrical connection at both the fuel
pressure manifold and fuel pump.

INJECTOR RAIL AND INJECTORS

The injector rail and injectors require no periodic
adjustment. You should annually inspect the following
items on the fuel rails and injectors.
• Check to make sure the rail bracket is securely
attached to the engine.
• Check to make sure the rail brackets have no
cracking or breaking.
• Check to make sure that each injector is securely
attached to the rail bracket.
• Check each injector electrical connection to insure
the connector is securely attached.
• Leak check all the connections on the manifold at
each injector connector, and the inlet and outlet
fitting at the rail, using an electronic leak detector or
a soapy solution.
• Check the injector delivery hose (if used) for any
cracking, kinky, cuts, or deformation, and replace if
necessary.

ELECTRICAL SYSTEM CHECKS

The electrical system, sensors, wiring harness, and
ECM do not require any periodic adjustments. You
should annually inspect the following items.
1-91
ECM SYSTEM
assembly. This manifold
KiSC issued 12, 2016 A