Spectrum 3.0L GM Quick start guide

2011 Emission Certified
LPG Fuel System
3.0L GM Engine
Parts & Service Manual
Including Labor Time Guide
Revision A/March, 2011

2011 Emission Certified
LPG Fuel System
3.0L GM Engine for
Parts & Service Manual
Table of Contents
General Information................................................................................................5
An overview of this Service Manual
Maintenance............................................................................................................9
General maintenance and maintenance interval information
Fuel System...........................................................................................................17
An overview of the LPG fuel system and its components
LPG Fuel System Diagnosis ................................................................................27
How to identify a general problem
LPG Symptom Diagnostics..................................................................................35
How to correct a specific problem
Electrical Section..................................................................................................51
Diagnostic Scan Tool......................................................................................53
Using the DST for testing and trouble shooting

Wire Schematic...................................................................................................81
Engine wiring schematics
Engine Wire Harness Repair .............................................................................85
Repairing a wire harness on the vehicle
Diagnostic Trouble Codes (DTCs) ....................................................................89
Application, schematic and DTC specific code information
Servicing the Fuel System.................................................................................... 237
Step by step instructions on how repair and/or replace fuel related Components
LPG Parts Diagram................................................................................................ 255
Illustrations and part views
Labor Time Guide .................................................................................................. 299
The labor reimbursed by IMPCO for warrantable service and repairs
Definitions .............................................................................................................. 317
Definitions of phrases and acronyms used throughout this Service Manual
Appendix ................................................................................................................ 323
Supplemental charts and tables

4

5
General Information

6
INTRODUCTION
This service manual supplement has been devel-
oped to provide the service technician with the
basic understanding of the IMPCO certified fuel
and emission systems for the 3.0L GM engine.
This manual should be used in conjunction with
the base engine manual and the OEM service
manual when diagnosing fuel or electrical prob-
lems.
HOW TO IDENTIFY THE ENGINE YEAR
The emission label on the engine will identify the
specific model year.
SERVICING YOUR EMISSIONS
CERTIFIED ENGINE
Any maintenance and repair should be performed
by trained and experienced service technicians.
Proper tools and equipment should be used to
prevent injury to the servicing technician and
damage to the vehicle or components. Service
repairs should always be performed in a safe envi-
ronment and the technician should always wear
protective clothing to prevent injury.
For parts or labor to be reimbursed under the
IMPCO Technologies Inc. emission warranty, only
work performed by IMPCO or OEM trained techni-
cians using only IMPCO specified parts will qualify
for reimbursement. Refer to the IMPCO Labor
Time Guide for additional information.
For parts or labor not reimbursed under warranty,
a repair shop or person of the owner’s choosing
may maintain, replace, or repair emission-control
devices and systems. It is highly recommended
that any replacement parts used for maintenance
or for the repair of emission control systems be
new OEM replacement parts. The use of other
than genuine IMPCO replacement parts may im-
pair the effectiveness of emission control systems,
therefore, the owner should assure that such parts
are warranted by their manufacturer to be equiva-
lent to genuine IMPCO OEM parts in performance
and durability.
FUEL QUALITY
LPG engines and fuel systems are designed to
operate on HD-5 or HD-10 specification LPG fuel.
Fuel other than HD-5 or HD-10 may cause harm
to the engine’s emission control system and a
warranty claim may be denied on this basis if op-
erators can readily find the proper fuel.* Use of
any other fuel may result in your engine no longer
operating in compliance with CARB or EPA emis-
sions requirements.
*Not Applicable in the state of California.
FUEL LINE CONNECTIONS
Loctite® 567 is recommended for all NPT connec-
tions.
Do not use Teflon tape to seal any fuel fit-
tings. Fragments of the tape may enter into
the fuel system, causing damage or mal-
function of critical fuel system components.
AIR FILTRATION REQUIREMENTS
Dry filtration is required with maximum recom-
mended 4” W.C. restriction @ 75 cfm. IMPCO
strongly recommends the use of OEM or factory
replacement parts.
WASHING
Caution should be used when pressure washing
near or on an engine’s electrical system. Avoid
direct pressure spray on the system electrical
connectors. The electrical connectors are splash
resistant, but if high pressure water or steam is
sprayed directly at the connectors, moisture can
become trapped behind the connector seal and
cause serious system problems, many of them
showing up as intermittent.

7
FUEL SYSTEM CAUTIONS
Do not use Teflon tape to seal any fuel
fittings. Fragments of the tape may en-
ter into the fuel system, causing
damage or malfunction of critical fuel
system components.
Do not smoke, carry lighted tobacco or
use a lighted flame of any type when
working on or near any fuel related
component. Highly flammable air-fuel
mixtures may be present and can be
ignited causing personal injury.
Do not allow LPG to contact the skin.
LPG is stored in the fuel tank as a liq-
uid. When LPG contacts the
atmosphere, it immediately expands in-
to a gas, resulting in a refrigeration
effect that can cause severe burns to
the skin.
Do not allow LPG to accumulate in
areas below ground level such as in a
service pit or underground ventilation
systems. LPG is heavier than air and
can displace oxygen, creating a dan-
gerous condition.
Do not make repairs to the fuel system
if you are not familiar with or trained to
service Propane fuel systems. Contact
the dealer who sold you the engine to
locate a repair facility with trained
technicians to repair your fuel system.
Unlike gasoline or propane vapors that
sink downward. Highly flammable
air/fuel mixtures may be present and
can be ignited causing personal injury.
Always work in well ventilated areas.
WARNINGS, CAUTIONS AND NOTES
This manual contains several different Warnings,
Cautions, and Notes that must be observed to
prevent personal injury and or damage to the en-
gine, the fuel system or personal property.
A “WARNING“ is an advisement that by perform-
ing a process or procedure listed in this manual
improperly may result in serious bodily injury,
death and/or serious damage to the engine or
property.
Typical Warning Label:
A “WARNING” is an advisement that
by performing a process or procedure
listed in this manual improperly may
result in serious bodily injury, death
and/or serious damage to the engine
or property.
A “CAUTION” label or statement is used when it
has been determine that by performing a process
or procedure defined in the manual improperly a
less severe result may occur. It could however,
result in serious bodily injury, and or serious dam-
age to the engine or property damage.
Less severe than WARNING but has
the potential to cause injury or dam-
age. Also used to notify of situations
that could lead to eventual failure, in-
jury or damage.
This caution label may also appear in area of this
manual that applies to service and repair proce-

8
dures. In addition it may also be used to indicate
a failure to observe which may influence the terms
of the warranty.
An “IMPORTANT” statement generally denotes a
situation that requires strict adherence to the as-
sembly, tightening, or service procedure. Failure
to observe this procedure could result in an un-
safe condition or improper performance of the
engine or a component.
A “NOTE” statement applies to a specific item or
procedure that is to be followed during the servic-
ing of the engine or its components.
PROPER USE OF THIS SERVICE MANUAL,
TOOLS AND EQUIPMENT
To reduce the potential for injury to the technician
or others and to reduce damage to the engine dur-
ing service repairs the technician should observe
the following Steps:
The service procedures defined in this ma-
nual, when followed, have been found to be a
safe and efficient process to repair the fuel
system. In some cases special tools may be
required to perform the necessary procedures
to safely remove and replace a failed compo-
nent.
Tools identified in this manual with the prefix
“J” or “BT” can be procured through SPX in
Warren, Michigan.
IMPCO tools identified in this manual with a
prefix “ITK” can be acquired through OEM
Parts Distribution.
IMPORTANT
It is important to remember that there may be a
combination of Metric and Imperial fasteners used
in the installation of the IMPCO fuel system.
Check to insure proper fit when using a socket or
wrench on any fastener to prevent damage to the
component being removed or injury from “slipping
off” the fastener.
The fuel system utilizes fuel lines and hoses with
high pressure connectors. Always use a wrench
of the proper size and torque to the correct value.
For hoses with swivel fittings, be sure not to turn
the fixed fitting which may cause a twisting or
kinking of the hose, possibly resulting in fuel line
restriction and/or leak.
Always leak check any fuel system con-
nection after servicing! Use an
electronic leak detector and/or a liquid
leak detection solution. Failure to leak
check could result in serious bodily in-
jury, death, or serious property damage.

9
Maintenance

10
MAINTENANCE
The maintenance of an engine and related com-
ponents are critical to its operating performance
and lifespan. Industrial engines operate in envi-
ronments that often include hot and cold
temperatures and extreme dust. The recom-
mended maintenance schedule is listed in this
section, however, environmental operating condi-
tions and additional installed equipment may
require more frequent inspection and servicing.
The owner and/or service agent should review the
operating conditions of the equipment to deter-
mine the inspection and maintenance intervals.
When performing maintenance on the engine,
turn the ignition OFF and disconnect the bat-
tery negative cable to avoid injury or damage
to the engine.
ENGINE BELTS
The engine installed in this equipment uses a ser-
pentine drive belt configuration that drives the
water pump, alternator and additional pumps or
devices. It is important to note that the drive belt
is an integral part of the cooling and charging sys-
tem and should be inspected according to the
maintenance schedule in this section. When in-
specting the belts check for:
Cracks
Chunking of the belt
Splits
Material hanging loose from the belt
Glazing, hardening
If any of these conditions exist the belt should be
replaced with the recommended OEM replace-
ment belt.
Alcohol or Methanol based anti-freeze or
plain water are not recommended for use in
the cooling system at anytime.
SERPENTINE BELT SYSTEM
Serpentine belts utilize a spring-loaded tensioner
to keep the belt properly adjusted. Serpentine
belts should be checked according to the main-
tenance schedule in this section.
IMPORTANT:
The use of “belt dressing” or “anti-slipping
agents” on belts is not recommended.
COOLING SYSTEM
It is important that the cooling system of the en-
gine be maintained properly to ensure proper
performance and longevity.
Alcohol or Methanol based anti-freeze or
plain water are not recommended for use
in the cooling system at anytime.
Do not remove the cooling system pres-
sure cap (radiator cap) when the engine is
hot. Allow the engine to cool and then
remove the cap slowly to allow pressure
to vent. Hot coolant under pressure may
discharge violently.
NOTE that the LPG vaporizer is connected to the
cooling system and the fuel system may be ad-
versely affected by low coolant levels and
restricted or plugged radiator cores. Therefore,
the cooling system must be maintained according
to the recommend maintenance schedule in this
section and also include:
The regular removal of dust, dirt and debris
from the radiator core and fan shroud.
Inspection of coolant hoses and components
for leaks, especially at the radiator hose con-
nections. Tighten hose clamps if necessary.
Check radiator hoses for swelling, separation,
hardening, cracks or any type of deterioration.