CLARK FORKLIFT IC201 Fuel Injection Systems TECHNICAL TRAINING MANUAL

IC201

Fuel Injection Systems

TECHNICAL TRAINING Copyrighted Material Intended for CLARK dealers only Do not sell or distribute

Copyrighted Material Intended for CLARK dealers only Do not sell or distribute

Contents About This Class....................................................................................... .

About Safety ...............................................................................................

About Carbon Monoxide........................................................................... ..

Definition of Terms................................................................................... .

Section 1. Fuel Injector System Operation...............................................

Gasoline System Operation........................................................... .

Component Location.......................................................................

Fuel Injectors...................................................................................

Filters...............................................................................................

Pumps..............................................................................................

Gasoline Regulators........................................................................

LPG System Operation.................................................................. .

LPG Regulators...............................................................................

LPG Fuel Tank................................................................................

LPG Service Valve...........................................................................

10% Withdrawal Valve....................................................................

Vent Valve.......................................................................................

Tank Fuel Gauge.............................................................................

Quick Disconnect Couplings...........................................................

Governor Operation........................................................................ .

Failsafe Modes................................................................................ .

Cold Start........................................................................................

Section 2. Maintenance and Troubleshooting Procedures...................... .

Fuel Filters ..................................................................................... .

Injector Flush..................................................................................

Cleaning Throttle Fly......................................................................

Checking Exhaust Emissions........................................................ .

Correcting Out of Range Air/Fuel Mixtures..................................

Ignition Timing Procedure.............................................................

Setting the Machanical Idle......................................................... ..

Idle Self Learn Procedure...............................................................

Special Tools ...................................................................................

Fuel Pressure Adjustments ........................................................... .

System Specifications..................................................................... .

Sensor Resistance Specifications.................................................. ..

Pedal Position Sensor Check..........................................................

Checking For Leaking Injectors.....................................................

Troubleshooting Flow Charts.........................................................

Schematics.......................................................................................

Section 3. Hybrid Micoprocessor Spark Timing System..........................

Computors and Voltage Signals .................................................... .

Sensors............................................................................................ .

Switch Types................................................................................... .

Engine Control Module (ECM).......................................................

Copyrighted Material Intended for CLARK dealers only Do not sell or distribute

3

4

5

6 7

7 10 11

12 12 12 13 13 14 14 14 15 15 15 16 17 17 18 18 18 18 18 19 20

21 22 23

24 26 27

28

29

30

45 50 50

51 52

53

IC 201 page l

Engine Coolant Temperatre Sensor (ECT)....................................

Manifold Absolute Pressw·e Sensor (MAP)....................................

ECM Self Diagnostics .................................. ....................................

Service Mode..... ......... ........................ ............................................. .

How Trouble Codes Are Set.................... .... ................................. ....

Service Precautions..........................................................................

Replacing Components.....................................................................

Troubleshooting the H-MSTS System.............................................

Trouble Code Chart..........................................................................

Clearing Trouble Codes....................................................................

© Copyright CLARK Material Handling Company 1999.

IC 201 page 2

Copyrighted Material Intended for CLARK dealers only Do not sell or distribute

54 55 55 55 56 57 58 62 62 63

About This Class Welcome to class IC-201: CLARK Fuel Injector Systems.

This class consists of Three sections: Fuel Injector System Operation Maintenance and Troubleshooting Procedures Hybrid Microprocessor Spark Timing System

CLARK Lift Truck internal combustion engines may be powered by carburetors or fuel injector systems.

Fuel Injection systems, Zenith Electronic Engine Management System, are used on later model CLARK trucks equipped with the 3.0U4 cylinder or 4.3U6 cylinder GM engines.

Two Fuel Injector systems are available for each engine. One system is for Gasoline only and one for Dual Fuel, (Gasoline and LPG). Both systems utilize many of the same components.

The purpose of this class is to introduce you to each of the two "Zeems" fuel injector systems, identify the components of each system, and examine how to troubleshoot and repair this system.

In addition, Fuel Injected Lift Trucks will have the GM Hybrid Microprocessor Spark Timing System. The GM H-MSTS module controls the engine's timing.

Discussions of components, maintenance and troubleshooting follow in all sections.

This training manual is not intended to replace the service manual. Please refer to the service manual for the lift truck model you are working on.

Copyrighted Material Intended for CLARK dealers only Do not sell or distribute

IC 201 page 3

Safety The following messages may be used to emphasize important information:

Note: This message is used when special information, instructions or identification is

required relating to procedures, equipment, tools, pressures, capacities and other special data.

Important: This message is used when special precautions should be taken to ensure a correct action or to avoid damage to or malfunction of the truck or a component.

CAUTION: This message is used as a reminder of safety practices which can result in personal injury if proper precautions are not taken.

WARNING: This message is used when a hazard exists which can result in injw-y or death if proper precautions are not taken.

DANGER: This message is used when an extreme hazard exists which will result in death or serious injw-y if proper precautions are not taken.

WARNING Always be sure to follow all safety precautions. Before you take any action, determine whether it could result in injury to yourself or a by­ stander. Always follow these safety guidelines: Park the truck in a well-ventilated area before working on it.

Avoid smoking or any open flame. There is always a danger of explosion when you are working around any fuel system.

Wear safety glasses.

Wear safety gloves, especially when working on high pressure, frosted lines or components.

Remove all jewelry. It may cause sparks or get caught on something.

DANGER

IC 201 page 4

Never attempt to operate a truck with a leak in the fuel system.

Copyrighted Material Intended for CLARK dealers only Do not sell or distribute

About Carbon Monoxide Carbon monoxide (CO) is a colorless, tasteless, and odorless gas and gives no warning of its presence. Those exposed to it do not realize it is present until symptoms begin to develop.

The exhaust emissions from internal combustion engines can increase through the lack of maintenance. This can cause the carbon monoxide inside a building to climb above the OSHA maximum limit of 50 ppm adveraged over an eight-hour period..

WARNING Procedures to vent the exhaust to a safe environment should be carried out during maintenance and repair procedw·es.

Effects of Carbon Monoxide Exposure Level of Exposure

Effects of Exposure

9 PPM (0.0009%)

The maximum allowable concentration for short-term exposw·e in living areas

50 PPM (0.005%)

The maximum allowable US OSHA concentration for continued exposure in any eight-hour period, according to federal law

200 PPM (0.02%)

Slight headaches, tiredness, dizziness, and nausea after 2 -3 hours

400 PPM (0.040%)

Frontal headache within1-2 hours. Life threatening after three hours. The maximum allowable Concentra­ tion according to the US EPA and AGA

800 PPM (0.08%)

Dizziness, Nausea, and convulsions within 45 minutes.

Death within1 hour

Copyrighted Material Intended for CLARK dealers only Do not sell or distribute

IC 201 page 5

Definition of Terms BAT

Battery Voltage

CAT

Catalyst or Catalytic converter

CKP

Crankshaft Position

CKPS

Crankshaft Position Sensor

DEG

Degrees

DI

Distibutor Ignition

DIAG

Diagnostic

DTC

Diagnostic Trouble Code

ECU

Electronic Control Unit

ECT

Engine Coolant Temperature

ECTS

Engine Coolant Temperature Sensor

EGO

Exhaust Gas Oxygen

EGOS

Exhaust Gas Oxygen Sensor

ESC

Electronic Spark Control

ESCM

Electronic Spark Control Module

HG

Inches of Mercury

IAT

Intake Air Temperature

IATS

Intake Air Temperature Sensor

IMAP

Intake Manifold Absolute Pressw·e

IMAPS

Intake Manifold Absolute Pressw·e Sensor

LPG

Liquid Petroleum Gas (propane)

NFPA

National Fire Protection Association

SFC

System Fault Code

SFL

System Fault Light

Vsw

Switched battery voltage

ZEEMS

Zenith Electronic Engine Management System

IC 201 page 6

Copyrighted Material Intended for CLARK dealers only Do not sell or distribute

Section 1. System Operation The spark-ignited engine (Otto Cycle) is a constant air-fuel ratio engine, and although the volume of air inside the cylinders remains constant, the density of air (MAP or Vacuum) varies according to the throttle position.

The Zenith Electronic Engine Management System (ZEEMS) controls both fuel delivery and the governor / throttle with an integrated throttle body and electronic control unit design. Each control system is described separately, but in actual operations control of fuel and throttle happen simultaneously.

Gasoline Fuel System Operation

Review of a gasoline carburetor system will aid in understanding the ZEEMS fuel system operation. Carburetors, mechanical fuel injection systems and electronic fuel injection systems all perform the same basic functions; however, the methods incorporated to per­ form these functions differ. The fundamental purpose of any fuel system is to measure the incoming air and mix the appropriate amount of fuel with it under all engine operat­ ing conditions. This applies equally to gasoline or LPG fuel systems. / ;

Float chamtJer needle valve

··· Float

I

\_

Idle speed _, \ control Idling mixture ___; butterfly control

\_

\ · · Main fuel jet

Acee le ration pump linkage

Typical Gasoline Carburetor The carburetor pe1forms three main functions.

To deliver a mixture of gas and air in a ratio that suits each condition of engine operation.

To atomize the gasoline as it enters the intake manifold.

To control the volume of air/ fuel delivered in response to throttle position and engine operation condition. In reality, each engine operating condition requires a circuit or mechanism to be designed into and attached to the gasoline carburetor to ensure that the engine will operate without hesitation or "flat-spot" and give maxi­ mum power with the optimum fuel economy within the levels of emissions for that model and year of engine design.

Copyrighted Material Intended for CLARK dealers only Do not sell or distribute

IC 201 page 7

The ZEEMS fuel injection system is based on the " speed-density" concept. The Elec­ tronic Control Unit, (ECU), uses engine RPM, Intake Manifold Absolute Pressure (IMAP), Intake Air Temperature (IAT), and Engine Coolant Temperature (ECT) to calculate the fuel required for a specific engine operating condition. By using RPM, IMAP, IAT and ECT to calculate intake manifold air density, the ECU calculates the correct fuel require­ ments regardless of machine geographic location.

INPUTS

OUTPUT

MANIFOLD ABSOLUTE PRESSURE ENGINE RPM ENGINE COOLANT TEMP .(ECT)

►

--1

INJECTOR

INTAKE AIR TEMP. (IAT)

When exhaust catalysts are needed to make the required emission standards, an exhaust gas oxygen sensor (EGOS) will be included to make further corrections to fuel require­ ments to enhance exhaust catalyst efficiency.

Once the required fuel delivery is calculated, fuel is delivered, at a pressure of10 psi, by the fuel pump and is injected via the fuel injector into the air stream above the throttle plate.

The fuel injector acts as a simple on/off solenoid. The volume of fuel flow is determined by varying the length of time the injector is held open by the ECU. This is known as pulse width modulation (PWM) and is measured in milliseconds. The injector is pulsed each time a spark plug fires. Each time a plug fires and that cylinder is in the power stroke, another cylinder is in the intake stroke. Between each spark plug firing, the ECU calcu­ lates the fuel required for the next engine event based on the information provided to the ECU.

IC 201 page 8

Copyrighted Material Intended for CLARK dealers only Do not sell or distribute