Spectrum 3.0L GM, Parts & Service Manual

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Spark Line:
The portion of an oscilloscope pattern
that represents the time during which the air/fuel
mixture is being burned in the combustion cham-
ber.
Splice:
An electrical term for the joining of two or
more conductors at a single point.
Stoichiometric Ratio:
An ideal fuel/air ratio for
combustion in which all of the fuel and most of
the oxygen will be burned.
Sulfur Oxides:
Chemical compounds where sulfur
is bonded to oxygen produced by the combustion
of gasoline or any other fuel that contains sulfur.
As sulfur oxides combine with water in the at-
mosphere to form sulfuric acid.
System Pressure:
The fuel pressure maintained in
the system during normal engine operation.
Tap:
An electrical term for a type of splice where
the original circuit is not interrupted.
TBI:
Throttle Body Injection. Any of several injec-
tion systems that have the fuel injector(s)
mounted in a centrally located throttle body.
Throttle Body:
Controls engine RPM by adjusting
the engine manifold vacuum to the mixer. Con-
sists of a housing shaft, throttle liner and butter
fl y
valve.
TLEV:
Transitional Low Emission Vehicle.
TMAP
: Combined Air Inlet and Manifold Pressure
Sensor.
Toluene:
A liquid aromatic hydrocarbon C
7
H
8
.
TPS:
Throttle Position Sensor.
TSB:
Technical Service Bulletin.
ULEV:
Ultra Low Emission Vehicle.
USB:
Universal Serial Bus. A plug or interface sup-
plied on most personal computers.
Vaporization
: A process in which liquid changes
states into gas.
Venturi Air Valve Vacuum (VAVV):
An ampli fi ed
air valve vacuum signal coming from the venturi
area of the mixer, directly exposed to air
fl ow be-
fore the addition of vaporized LPG.
Volt/ohmmeter
(VOM): A combination meter used
to measure voltage and resistance in an electrical
circuit. Available in both analog and digital types.
May also referred to as AVOM and DVOM.
Voltage:
The electrical pressure that causes cur-
rent to fl ow in a circuit. Measured in volts.
Voltage Drop:
A lowering of the voltage in a circuit
when resistance or electrical load is added.
Voltmeter:
A meter that uses a needle to point to a
value on a scale of numbers usually of the low
impedance type; used
to measure voltage and
resistance.
VSS:
Vehicle Speed Sensor
Xylene
: C
6
H
4
(CH
3
)
2
. Any of three toxic, fl ammable,
and oily isomeric aromatic hydrocarbons that are
dimethyl homologues of benzene and usually ob-
tained from petroleum or natural gas distillates.
ZEV:
Zero Emission Vehicle.