1988 OPEL VECTRA jump start terminals

1General information and
precautions
The electrical system is of 12-volt negative
earth type. Power for the lights and all
electrical accessories is supplied by a
lead/acid type battery, which is charged by
the alternator.
This Chapter covers repair and service
procedures for the various electrical
components not associated with engine.
Information on the battery, alternator and
starter motor can be found in Chapter 5.
It should be noted that, before working on
any component in the electrical system, the
battery negative terminal should first be
disconnected, to prevent the possibility of
electrical short-circuits and/or fires.
Whenever the occasion arises, carefully
check the routing of the wiring harness,
ensuring that it is correctly secured by the
clips or ties provided so that it cannot chafe
against other components. Carefully check
points such as the clutch cable bracket,
clutch housing and harness support bracket,
the inlet manifold, the horn mounting bracket,
the starter motor terminals, and the rear
bumper and number plate lamp.
If evidence is found of the harness having
chafed against other components, repair the
damage and ensure that the harness is
secured or protected so that the problem
cannot occur again.
2Electrical fault-finding -
general information
Note:Refer to the precautions given in “Safety
first!” (at the beginning of this manual) and to
Section 1 of this Chapter before starting work.
The following tests relate to testing of the main
electrical circuits, and should not be used to
test delicate electronic circuits (such as anti-
lock braking systems), particularly where an
electronic control module is used.
A typical electrical circuit consists of an
electrical component, any switches, relays,
motors, fuses, fusible links or circuit breakers
related to that component, and the wiring and
connectors that link the component to boththe battery and the chassis. To help to
pinpoint a problem in an electrical circuit,
wiring diagrams are included at the end of this
Chapter.
Before attempting to diagnose an electrical
fault, first study the appropriate wiring
diagram, to obtain a complete understanding
of the components included in the particular
circuit concerned. The possible sources of a
fault can be narrowed down by noting
whether other components related to the
circuit are operating properly. If several
components or circuits fail at one time, the
problem is likely to be related to a shared fuse
or earth connection.
Electrical problems usually stem from
simple causes, such as loose or corroded
connections, a faulty earth connection, a
blown fuse, a melted fusible link, or a faulty
relay (refer to Section 3 for details of testing
relays). Visually inspect the condition of all
fuses, wires and connections in a problem
circuit before testing the components. Use
the wiring diagrams to determine which
terminal connections will need to be checked,
to pinpoint the trouble-spot.
The basic tools required for electrical fault-
finding include the following:
a)a circuit tester or voltmeter (a 12-volt bulb
with a set of test leads can also be used
for certain tests).
b)a self-powered test light (sometimes
known as a continuity tester).
c)an ohmmeter (to measure resistance).
d)a battery.
e)a set of test leads.
f)a jumper wire, preferably with a circuit
breaker or fuse incorporated, which can
be used to bypass suspect wires or
electrical components.
Before attempting to locate a problem with
test instruments, use the wiring diagram to
determine where to make the connections.
To find the source of an intermittent wiring
fault (usually due to a poor or dirty
connection, or damaged wiring insulation), a
“wiggle” test can be performed on the wiring.
This involves wiggling the wiring by hand, to
see if the fault occurs as the wiring is moved.
It should be possible to narrow down the
source of the fault to a particular section of
wiring. This method of testing can be used in
conjunction with any of the tests described in
the following sub-Sections.
Apart from problems due to poor
connections, two basic types of fault can
occur in an electrical circuit - open-circuit, or
short-circuit.
Open-circuit faults are caused by a break
somewhere in the circuit, which prevents
current from flowing. An open-circuit fault will
prevent a component from working, but will
not cause the relevant circuit fuse to blow.
Short-circuit faults are caused by a “short”
somewhere in the circuit, which allows the
current flowing in the circuit to “escape” along
an alternative route, usually to earth. Short-
circuit faults are normally caused by abreakdown in wiring insulation, which allows a
feed wire to touch either another wire, or an
earthed component such as the bodyshell. A
short-circuit fault will normally cause the
relevant circuit fuse to blow.
Finding an open-circuit
To check for an open-circuit, connect one
lead of a circuit tester or voltmeter to either
the negative battery terminal or a known good
earth.
Connect the other lead to a connector in
the circuit being tested, preferably nearest to
the battery or fuse.
Switch on the circuit, remembering that
some circuits are live only when the ignition
switch is moved to a particular position.
If voltage is present (indicated either by the
tester bulb lighting or a voltmeter reading, as
applicable), this means that the section of the
circuit between the relevant connector and
the battery is problem-free.
Continue to check the remainder of the
circuit in the same fashion.
When a point is reached at which no
voltage is present, the problem must lie
between that point and the previous test point
with voltage. Most problems can be traced to
a broken, corroded or loose connection.
Finding a short-circuit
To check for a short-circuit, first disconnect
the load(s) from the circuit (loads are the
components that draw current from a circuit,
such as bulbs, motors, heating elements, etc.).
Remove the relevant fuse from the circuit,
and connect a circuit tester or voltmeter to the
fuse connections.
Switch on the circuit, remembering that
some circuits are live only when the ignition
switch is moved to a particular position.
If voltage is present (indicated either by the
tester bulb lighting or a voltmeter reading, as
applicable), this means that there is a short-
circuit.
If no voltage is present, but the fuse still
blows with the load(s) connected, this indicates
an internal fault in the load(s).
Finding an earth fault
The battery negative terminal is connected
to “earth” (the metal of the
engine/transmission and the car body), and
most systems are wired so that they only
receive a positive feed. The current returning
through the metal of the car body. This means
that the component mounting and the body
form part of that circuit. Loose or corroded
mountings can therefore cause a range of
electrical faults, ranging from total failure of a
circuit, to a puzzling partial fault. In particular,
lights may shine dimly (especially when
another circuit sharing the same earth point is
in operation). Motors (e.g. wiper motors or the
radiator cooling fan motor) may run slowly,
and the operation of one circuit may have an
affect on another. Note that on many vehicles,
earth straps are used between certain
components, such as the engine/transmission
and the body, usually where there is no metal-
12•2Body electrical systems
Warning: Before carrying out
any work on the electrical
system, read through the
precautions given in “Safety
first!” at the beginning of this manual, and
in Chapter 5.
Caution:If the radio/cassette player fitted
to the vehicle is one with an anti-theft
security code, as the standard unit is, refer
to “Radio/cassette player anti-theft system
- precaution”in the Reference Section of
this manual before disconnecting the
battery.

Distributor
Direction of rotor arm rotation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Anti-clockwise (viewed from cap)
Firing order . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-3-4-2 (No 1 cylinder at timing belt end of engine)
Dwell angle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Automatically controlled by electronic module (not adjustable)
Ignition timing
14 NV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5°BTDC
16 SV, X 16 SZ, C 16 NZ, C 16 NZ2 and C 18 NZ . . . . . . . . . . . . . . . .10°BTDC *
18 SV and 2.0 litres models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 to 12°BTDC *
* Ignition timing electronically controlled no adjustment possible
Spark plugs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .See Chapter 1 Specifications
Torque wrench settingNmlbf ft
Alternator mounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2518
Camshaft phase sensor disc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .86
Camshaft phase sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1511
‘Compact’ series alternator lower mounting bolt . . . . . . . . . . . . . . . . . .3526
‘Compact’ series alternator upper mounting bolts . . . . . . . . . . . . . . . . .2015
DIS module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .75
Inductive pulse pick-up to block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .86
Spark plugs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2518
Starter motor mounting bracket-to-cylinder block . . . . . . . . . . . . . . . . .2518
Starter motor mounting:
1.4 and 1.6 litre models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2518
1.8 and 2.0 litre models:
Engine side . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4533
Transmission side . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7555
1Electrical system - general
1The electrical system is of the 12 volt
negative earth type, and consists of a 12 volt
battery, alternator with integral voltage
regulator, starter motor, and related electrical
accessories, components and wiring.
2The battery is of the maintenance-free
“sealed for life” type, and is charged by an
alternator, which is belt-driven from the
crankshaft pulley. The starter motor is of the
pre-engaged type, incorporating an integral
solenoid. On starting, the solenoid moves the
drive pinion into engagement with the flywheel
ring gear before the starter motor is
energised. Once the engine has started, a
one-way clutch prevents the motor armature
being driven by the engine until the pinion
disengages from the flywheel.
3It is necessary to take extra care when
working on the electrical system, to avoid
damage to semi-conductor devices (diodes
and transistors), and to avoid the risk of
personal injury. Along with the precautions
given in the “Safety first!” Section at the
beginning of this manual, take note of the
following points when working on the system.4Always remove rings, watches, etc. before
working on the electrical system. Even with
the battery disconnected, discharge could
occur if a component live terminal is earthed
through a metal object. This could cause a
shock or nasty burn.
5Do not reverse the battery connections.
Components such as the alternator, or any
other component having semi-conductor
circuitry, could be irreparably damaged.
6If the engine is being started using jump
leads and a slave battery, connect the
batteries positive to positive and negative to
negative. This also applies when connecting a
battery charger.
7Never disconnect the battery terminals, or
alternator multi-plug connector, when the
engine is running.
8The battery leads and alternator wiring
must be disconnected before carrying out any
electric welding on the vehicle.
9Never use an ohmmeter of the type
incorporating a hand-cranked generator for
circuit or continuity testing.
2Ignition system - general
1The ignition system is responsible for
igniting the air/fuel mixture in each cylinder at
the correct moment, in relation to engine
speed and load. A number of different types
of ignition systems are fitted to models within
the range. Ranging from a basic breakerless
electronic system, to a fully integrated engine
management system controlling both ignition
and fuel injection systems. Each system isdescribed in further detail later in this Section.
2The ignition system is based on feeding low
tension voltage from the battery to the coil,
where it is converted to high tension voltage.
The high tension voltage is powerful enough
to jump the spark plug gap in the cylinders
many times a second under high compression
pressures, providing that the system is in
good condition. The low tension (or primary)
circuit consists of the battery, the lead to the
ignition switch. The lead from the ignition
switch to the low tension coil windings and
the supply terminal on the electronic module.
The lead from the low tension coil windings to
the control terminal on the electronic module.
The high tension (or secondary) circuit
consists of the high tension coil windings, the
HT (high tension) lead from the coil to the
distributor cap, the rotor arm, the HT leads to
the spark plugs, and the spark plugs.
3The system functions in the following
manner. Current flowing through the low
tension coil windings produces a magnetic
field around the high tension windings. As the
engine rotates, a sensor produces an
electrical impulse that is amplified in the
electronic module and used to switch off the
low tension circuit.
4The subsequent collapse of the magnetic
field over the high tension windings produces
a high tension voltage, which is then fed to the
relevant spark plug through the distributor
cap and rotor arm. The low tension circuit is
automatically switched on again by the
electronic module, to allow the magnetic field
to build up again before the firing of the next
spark plug. The ignition is advanced and
retarded automatically, to ensure that the
spark occurs at the correct instant with the
engine speed and load.
5•2Engine electrical systems
Caution: Before carrying out
any work on the vehicle
electrical system, read through
the precautions given in the
“Safety first!” Section at the beginning of
this manual, and in Section 3 of this
Chapter.

28The system also incorporates a separate
ignition amplifier module that transmits
amplified signals from the main system
module to trigger the HT pulse from the
ignition coil. The module is mounted on the
ignition coil’s bracket/baseplate.
29Additionally, the Motronic module
receives information from a cylinder
block-mounted knock sensor, which senses
“knocking” (or pre-ignition) just as it begins to
occur, enabling the module to retard the
ignition timing, thus preventing engine
damage.
Simtec 56.1
30This system uses increased amount of
electronic components instead of mechanical
parts as sensors and actuators with the
Simtec engine management system. This
provides more precise operating data as well
as greater problem free motoring.
31The control unit is equipped with
electronic ignition control. Called ‘Micropro-
cessor Spark Timing System, inductive
triggered’, (or MSTS-i), and means that the
mechanical high voltage distributor is no
longer needed. It is located behind the trim
panel, on the right-hand side footwell (door
pillar).
32The ignition coil is replaced by a dual
spark ignition coil, which is switched directly
by the output stages in the control unit.
33A camshaft sensor will maintain
emergency operation, should the crankshaft
inductive pulse pick-up, malfunction. These
sense TDC (‘Top Dead Centre’), crankshaft
angle and engine speed. The signals are used
by the control unit to calculate ignition point
and for fuel injection.
34The ‘hot film airflow meter’ determines the
mass of air taken in by the engine. The system
uses this information to calculate the correct
amount of fuel needed for injection in the
engine.
35The air inlet temperature sensor (NTC), is
fitted in the air inlet duct between the air
cleaner and the hot mass air flow meter.
36A controlled canister purge valve is
actuated by the system. The tank ventilation is
monitored closely with the Lambda control (or
oxygen sensor) and adaptation by the
computer within the control unit.
37A knock control system is also fitted. This
eliminates the need for octane number
adjustment, as it is performed automatically
through the control unit.
3Electrical system -
precautions
1It is necessary to take extra care when
working on the electrical system, to avoid
damage to semi-conductor devices (diodes
and transistors), and to avoid the risk of
personal injury. Along with the precautions
given in the “Safety first!” Section at the
beginning of this manual, take note of the
following points when working on the system.
2Always remove rings, watches, etc. before
working on the electrical system. Even with
the battery disconnected, discharge could
occur if a component live terminal is earthed
through a metal object. This could cause a
shock or nasty burn.
3Do not reverse the battery connections.
Components such as the alternator, or any
other component having semi-conductor
circuitry, could be irreparably damaged.
4If the engine is being started using jump
leads and a slave battery, connect the
batteries positive to positive and negative to
negative. This also applies when connecting a
battery charger.
5Never disconnect the battery terminals, or
alternator multi-plug connector, when the
engine is running.
6The battery leads and alternator wiring
must be disconnected before carrying out any
electric welding on the vehicle.
7Never use an ohmmeter of the type
incorporating a hand-cranked generator for
circuit or continuity testing.
8Engine management modules are very
sensitive components, and certain
precautions must be taken, to avoid damage
to the module when working on a vehicle
equipped with an engine management
system, as follows.
9When carrying out welding operations on
the vehicle using electric welding equipment,
the battery and alternator should be
disconnected.
10Although underbonnet-mounted modules
will tolerate normal underbonnet conditions,
they can be adversely affected by excess heat
or moisture. If using welding equipment or
pressure washing equipment near the
module, take care not to direct heat, or jets of
water or steam, at the module. If this cannot
be avoided, remove the module from the
vehicle, and protect its wiring plug with a
plastic bag.
11Before disconnecting any wiring, or
removing components, always ensure that the
ignition is switched off.
12Do not attempt to improvise fault
diagnosis procedures using a test lamp or
multimeter, as irreparable damage could be
caused to the module.13After working on ignition/engine
management system components, ensure
that all wiring is correctly reconnected before
reconnecting the battery or switching on the
ignition.
14Any ignition system that uses a
“Hall-effect” generator in the distributor,
cannot be tested. Test equipment that uses
its own power source (e.g. an ohmmeter),
when connected to the distributor or the
“Hall-effect” generator, will be damaged.
4Ignition system testing -
general
3
Note: Refer to Section 3 before proceeding.
Always switch off the ignition before
disconnecting or connecting any component
and when using a multi-meter to check
resistances. Any voltmeter or multi-meter
used to test ignition system components must
have an impedance of 10 meg ohms or
greater
1Electronic ignition system components are
normally very reliable. Most faults are far more
likely to be due to loose or dirty connections,
or to “tracking” of HT voltage due to dirt,
dampness or damaged insulation than to
component failure. Always check all wiring
thoroughly before condemning an electrical
component and work methodically to
eliminate all other possibilities before deciding
that a particular component is faulty.
2The old practice of checking for a spark by
holding the live end of a HT lead a short
distance away from the engine is not
recommended. Not only is there a high risk of
a powerful electric shock, but the ignition coil
or amplifier module will be damaged.
Similarly, never try to “diagnose” misfires by
pulling off one HT lead at a time. Note also
that the ECU is at risk if the system is
triggered with an open (i.e., not properly
earthed) HT circuit; ECU’s are very expensive
to replace, so take care!
3If you are in any doubt as to your skill and
ability to test an ignition system component or
if you do not have the required equipment,
take the vehicle to a suitably equipped
Vauxhall dealer. It is better to pay the labour
charges involved in having the vehicle
checked by an expert than to risk damage to
the system or to yourself.
4If the engine either will not turn over at all,
or only turns very slowly, check the battery
and starter motor. Connect a voltmeter across
the battery terminals (meter positive probe to
battery positive terminal) and disconnect the
ignition coil HT lead from the distributor cap
and earth. Note the voltage reading obtained
while turning over the engine on the starter for
(no more than) ten seconds. If the reading
obtained is less than approximately 9.5 volts,
check the battery, battery connections, starter
motor and charging system.
5•4Engine electrical systems
Warning: The HT voltage
generated by an electronic
ignition system is extremely
high and, in certain
circumstances, could prove fatal. Take
care to avoid receiving electric shocks
from the HT side of the ignition system.
Do not handle HT leads, or touch the
distributor or coil, when the engine is
running. If tracing faults in the HT circuit,
use well-insulated tools to manipulate live
leads

5If the engine turns over at normal speed but
will not start, check the HT circuit by
connecting a timing light and turning the
engine over on the starter motor. If the light
flashes, voltage is reaching the spark plugs,
so these should be checked first. If the light
does not flash, check the HT leads
themselves followed by the distributor cap,
carbon brush and rotor arm.
6If there is a spark, check the fuel system for
faults as far as possible (Chapters 4A or 4B).
7If there is still no spark, check the voltage at
the ignition coil “+” or “15” terminal; it should
be the same as the battery voltage (i.e., at
least 11.7 volts). If the voltage at the coil is
more than 1 volt less than that at the battery,
check the connections back through the
ignition switch to the battery and its earth until
the fault is found. Note, however, that the
ECU controls the coil’s feed; do not attempt
to “test” the ECU with anything other than the
correct test equipment, which will be available
only to a Vauxhall dealer. If any of the wires
are to be checked which lead to the ECU,
always first unplug the relevant connector
from the ECU so that there is no risk of the
ECU being damaged by the application of
incorrect voltages from test equipment.
8If the feed to the ignition coil is sound,
check the coil’s primary and secondary
windings (refer to Section 16). Renew the coil
if faulty, but check the condition of the LT
connections themselves before doing so, to
ensure that the fault is not due to dirty or
poorly fastened connectors.
9If the ignition coil is in good condition, the
fault may be within the amplifier module or the
distributor on the C16 NZ and C16 NZ2
engines, or the amplifier or the crankshaft
speed/position sensor on the C18 NZ engine.
A quick check of these components can be
made by connecting a low-wattage bulb
across the ignition coil’s (disconnected) LT
terminals. If the bulb flickers or flashes when
the engine is turned over, the amplifier and
distributor (C16 NZ and C16 NZ2 engines), or
amplifier and crankshaft speed/position
sensor (C18 NZ engine), are sound.
10If this is the case, the entire LT circuit is in
good condition; the fault, if it lies in the
ignition system, must be in the HT circuit
components. These should be checked
carefully, as outlined above.
11If the indicator or bulb does not flash, the
fault is in either the amplifier or the distributor
(C16 NZ and C16 NZ2 engines), or the
amplifier or crankshaft speed/position sensor
(C18 NZ engine). Owners should note,
however, that by far the commonest cause of
“failure” of either of these is a poor
connection, either between the components
themselves or in the LT circuit wiring
connections. If such a fault is suspected, the
vehicle must be taken to a suitably equipped
Vauxhall dealer for testing; no information is
available to eliminate these components by
other means.12An irregular misfire suggests either a
loose connection or intermittent fault on the
primary circuit, or a HT fault on the coil side of
the rotor arm.
13With the ignition switched off, check
carefully through the system ensuring that all
connections are clean and securely fastened.
If the equipment is available, check the LT
circuit as described in paragraphs 7 to 11
above.
14Check that the HT coil, the distributor cap
and the HT leads are clean and dry. Check the
leads and the spark plugs (by substitution, if
necessary), then check the distributor cap,
carbon brush and rotor arm.
15Regular misfiring is almost certainly due to
a fault in the distributor cap, HT leads or spark
plugs. Use a timing light (paragraph 5, above)
to check whether HT voltage is present at all
leads.
16If HT voltage is not present on any
particular lead, the fault will be in that lead or
in the distributor cap. If HT is present on all
leads, the fault will be in the spark plugs;
check and renew them if there is any doubt
about their condition.
17If no HT voltage is present, check the
ignition coil; its secondary windings may be
breaking down under load.
18If all components have been checked for
signs of obvious faults but the system is still
thought to be faulty, take the vehicle to a
Vauxhall dealer for testing on special
equipment.
5Battery - testing and charging
2
Note: Refer to Section 3 before proceeding.
Testing
1Topping-up and testing of the electrolyte in
each cell is not possible. The condition of the
battery can therefore only be tested by
observing the battery condition indicator.
2The battery condition indicator is fitted in
the top of the battery casing, and indicates
the condition of the battery from its colour. If
the indicator shows green, then the battery is
in a good state of charge. If the indicator turns
darker, eventually to black, then the battery
requires charging, as described later in this
Section. If the indicator shows clear/yellow,
then the electrolyte level in the battery is too
low to allow further use, and the battery
should be renewed.
Charging
3Do not attempt to charge, load or jump start
a battery when the indicator shows
clear/yellow. If the battery is to be charged,
remove it from the vehicle and charge it as
follows.
4The maintenance-free type battery takes
considerably longer to fully recharge than the
standard type, the time taken being
dependent on the extent of discharge.5A constant-voltage type charger is required,
to be set, when connected, to 13.9 to 14.9
volts with a charger current below 25 amps.
6If the battery is to be charged from a fully
discharged state (less than 12.2 volts output),
have it recharged by a Vauxhall dealer or
battery specialist, as the charge rate will be
high and constant supervision during charging
is necessary.
6Battery - removal and refitting
2
Note: Refer to Section 3 before proceeding.
Removal
1The battery is located at the left-hand front
corner of the engine compartment.
2Disconnect the lead(s) at the negative
(earth) terminal by unscrewing the retaining
nut and removing the terminal clamp.
3Disconnect the positive terminal lead(s) in
the same way.
4Unscrew the clamp bolt sufficiently to
enable the battery to be lifted from its
location. Keep the battery in an upright
position, to avoid spilling electrolyte on the
bodywork.
Refitting
5Refitting is a reversal of removal, but smear
petroleum jelly on the terminals when
reconnecting the leads, and always connect
the positive lead first and the negative lead
last.
7Alternator - description
1A Delco-Remy or Bosch alternator may be
fitted, depending on model and engine
capacity. The maximum output of the
alternator varies accordingly.
2The alternator is belt-driven from the
crankshaft pulley. Cooling is provided by a
fan, mounted outside the casing on the end of
the rotor shaft. An integral voltage regulator is
incorporated, to control the output voltage.
3The alternator provides a charge to the
battery even at very low engine speed, and
consists of a coil-wound stator in which a
rotor rotates. The rotor shaft is supported in
ball-bearings, and slip rings are used to
conduct current to and from the field coils
through the carbon brushes.
4The alternator generates ac (alternating
current), which is rectified by an internal diode
circuit to dc (direct current) for supply to the
battery.
5Later models are fitted with a Delco-Remy,
‘compact’ series alternators (see illustration).
They use a ribbed V-belt type drivebelt with
automatic tensioner. They are rigidly mounted
to the engine.
Engine electrical systems 5•5
5

Glossary of Technical Terms REF•23
JJump startStarting the engine of a vehicle
with a discharged or weak battery by
attaching jump leads from the weak battery to
a charged or helper battery.
LLoad Sensing Proportioning Valve (LSPV)A
brake hydraulic system control valve that
works like a proportioning valve, but also
takes into consideration the amount of weight
carried by the rear axle.
LocknutA nut used to lock an adjustment
nut, or other threaded component, in place.
For example, a locknut is employed to keep
the adjusting nut on the rocker arm in
position.
LockwasherA form of washer designed to
prevent an attaching nut from working loose.
MMacPherson strutA type of front
suspension system devised by Earle
MacPherson at Ford of England. In its original
form, a simple lateral link with the anti-roll bar
creates the lower control arm. A long strut - an
integral coil spring and shock absorber - is
mounted between the body and the steering
knuckle. Many modern so-called MacPherson
strut systems use a conventional lower A-arm
and don’t rely on the anti-roll bar for location.
MultimeterAn electrical test instrument with
the capability to measure voltage, current and
resistance.
NNOxOxides of Nitrogen. A common toxic
pollutant emitted by petrol and diesel engines
at higher temperatures.
OOhmThe unit of electrical resistance. One
volt applied to a resistance of one ohm will
produce a current of one amp.
OhmmeterAn instrument for measuring
electrical resistance.
O-ringA type of sealing ring made of a
special rubber-like material; in use, the O-ring
is compressed into a groove to provide the
sealing action.Overhead cam (ohc) engineAn engine with
the camshaft(s) located on top of the cylinder
head(s).
Overhead valve (ohv) engineAn engine with
the valves located in the cylinder head, but
with the camshaft located in the engine block.
Oxygen sensorA device installed in the
engine exhaust manifold, which senses the
oxygen content in the exhaust and converts
this information into an electric current. Also
called a Lambda sensor.
PPhillips screwA type of screw head having a
cross instead of a slot for a corresponding
type of screwdriver.
PlastigageA thin strip of plastic thread,
available in different sizes, used for measuring
clearances. For example, a strip of Plastigage
is laid across a bearing journal. The parts are
assembled and dismantled; the width of the
crushed strip indicates the clearance between
journal and bearing.
Propeller shaftThe long hollow tube with
universal joints at both ends that carries
power from the transmission to the differential
on front-engined rear wheel drive vehicles.
Proportioning valveA hydraulic control
valve which limits the amount of pressure to
the rear brakes during panic stops to prevent
wheel lock-up.
RRack-and-pinion steeringA steering system
with a pinion gear on the end of the steering
shaft that mates with a rack (think of a geared
wheel opened up and laid flat). When the
steering wheel is turned, the pinion turns,
moving the rack to the left or right. This
movement is transmitted through the track
rods to the steering arms at the wheels.
RadiatorA liquid-to-air heat transfer device
designed to reduce the temperature of the
coolant in an internal combustion engine
cooling system.
RefrigerantAny substance used as a heat
transfer agent in an air-conditioning system.
R-12 has been the principle refrigerant for
many years; recently, however, manufacturers
have begun using R-134a, a non-CFC
substance that is considered less harmful tothe ozone in the upper atmosphere.
Rocker armA lever arm that rocks on a shaft
or pivots on a stud. In an overhead valve
engine, the rocker arm converts the upward
movement of the pushrod into a downward
movement to open a valve.
RotorIn a distributor, the rotating device
inside the cap that connects the centre
electrode and the outer terminals as it turns,
distributing the high voltage from the coil
secondary winding to the proper spark plug.
Also, that part of an alternator which rotates
inside the stator. Also, the rotating assembly
of a turbocharger, including the compressor
wheel, shaft and turbine wheel.
RunoutThe amount of wobble (in-and-out
movement) of a gear or wheel as it’s rotated.
The amount a shaft rotates “out-of-true.” The
out-of-round condition of a rotating part.
SSealantA liquid or paste used to prevent
leakage at a joint. Sometimes used in
conjunction with a gasket.
Sealed beam lampAn older headlight design
which integrates the reflector, lens and
filaments into a hermetically-sealed one-piece
unit. When a filament burns out or the lens
cracks, the entire unit is simply replaced.
Serpentine drivebeltA single, long, wide
accessory drivebelt that’s used on some
newer vehicles to drive all the accessories,
instead of a series of smaller, shorter belts.
Serpentine drivebelts are usually tensioned by
an automatic tensioner.
ShimThin spacer, commonly used to adjust
the clearance or relative positions between
two parts. For example, shims inserted into or
under bucket tappets control valve
clearances. Clearance is adjusted by
changing the thickness of the shim.
Slide hammerA special puller that screws
into or hooks onto a component such as a
shaft or bearing; a heavy sliding handle on the
shaft bottoms against the end of the shaft to
knock the component free.
SprocketA tooth or projection on the
periphery of a wheel, shaped to engage with a
chain or drivebelt. Commonly used to refer to
the sprocket wheel itself.
Starter inhibitor switchOn vehicles with an
O-ring
Serpentine drivebelt
Plastigage
REF