Spectrum 3.0L GM, Parts & Service Manual

Page: 319 / 327

319
Ethanol:
Grain alcohol (C
2
H
5
OH), generally pro-
duced by fermenting starch or sugar.
Evaporative Emissions Controls:
An automotive
emission control system designed to reduce hy-
drocarbon emissions by trapping evaporated fuel
vapors from the fuel system.
Excess Flow Valve:
A check valve that is caused
to close by the fuel when the fl ow exceeds a pre-
determined rate.
FTV:
Fuel Trim Valve.
FFV
: Flexible Fuel Vehicle.
Firing Line:
The portion of an oscilloscope pattern
that represents the total amount of voltage being
expended through the secondary circuit.
FMVSS:
Federal Motor Vehicle Safety Standards.
FPP:
Foot Pedal Position Sensor
Fuel Injector:
a spring loaded, electromagnetic
valve which delivers fuel into the intake manifold,
in response to an electrical input from the control
module.
Fuel Lock:
A solenoid-controlled valve located in
the fuel line to stop the fl ow when the engine
stops or the ignition switch is off.
Gasohol:
10 percent ethanol, 90 percent gasoline.
Often referred to as E-10.
Gasoline:
A motor vehicle fuel that is a complex
blend of hydrocarbons and additives. Typical oc-
tane level is 89.
GCP:
Spectrum III (90-pin) ECM.
Greenhouse Effect:
A scienti fi c theory suggesting
that carbon dioxide from the burning of fossil fuels
is causing the atmosphere to trap heat and cause
global warming.
HC:
Hydrocarbon. An organic chemical compound.
HD 10:
A fuel of not less than 80% liquid volume
propane and not more than 10% liquid volume
propylene.
HD 5:
A fuel of not less than 90% liquid volume
propane and not more than 5% liquid volume
propylene.
HDV:
Heavy Duty Vehicle.
Heavy Ends:
A term used to describe the buildup
of wax-like impurities that fall out of LPG when
vaporized.
HEGO:
Heated Exhaust Gas Oxygen, used to de-
scribe a sensor. Also known as “EGO” (Exhaust
Gas Oxygen sensor), “O
2
” or “Oxygen sensor.
Hg:
Chemical symbol for the element mercury.
Used in reference to a measure of vacuum (inch-
es of Hg).
Histogram:
T
he graphical version of a table which
shows what proportion of values fall into specific
categories over a specific period of time.
Hydrocarbon:
A chemical compound made up of
hydrogen and carbon (HC). Gasoline and almost
all other fuels are hydrocarbons.
Hydrostatic Relief Valve:
A pressure relief device
installed in the liquid LPG hose on a LPG fuel
system.
IAT:
Intake Air Temperature
Ideal Mixture:
The air/fuel ratio at which the best
compromise of engine performance to exhaust
emissions is obtained. Typically 14.7:1.
Ignition Reserve:
The difference between availa-
ble voltage and the required voltage.
ILEV:
Inherently Low Emission Vehicle.
IMPCO:
Imperial Machine Products Company.
IMPCO Technologies, Inc.
A manufacturer of both
LPG and Gasoline fuel systems.
Impedance
: A form of opposition of AC electrical
current fl ow (resistance) measured in ohms.
Insulation:
A nonconductive material used to cover
wires in electrical circuits to prevent the leakage
of electricity and to protect the wire from corro-
sion.
Intercept:
An electrical term for a type of splice
where the original circuit is interrupted and redi-
rected through another circuit.
ITK:
IMPCO Test Kit
Knock:
Sound produced when an engine’s air/fuel
mixture is ignited by something other than the
spark plug, such as a hot spot in the combustion
chamber. Also caused by a fuel with an octane
rating that is too low and/or incorrect ignition tim-
ing. Also called detonation or ping.
Lambda Sensor:
A feedback device, usually lo-
cated in the exhaust manifold, which detects the
amount of oxygen present in exhaust gases in re-
lation to the surrounding atmosphere. (See
HEGO).
LDV:
Light Duty Vehicle.
Lean Mixture:
An air to fuel ratio above the stoi-
chiometric ratio; too much air .
LEV:
Low Emission Vehicle .
Limp-in or Limp Home:
A mode where the ECM
or a component has failed, but the vehicle re-
mains operational although the engine may
operate minimally. This term may also describe
the drivability characteristics of a failed computer
system.
Liquid Petroleum Gas (LPG):
A fuel commonly
known as propane consisting mostly of propane
(C
3
H
8
), derived from the liquid components of
natural gas stripped out before the gas enters the
pipeline, and the lightest hydrocarbons produced
during petroleum re
fi ning. Octane level of LPG is
107.