tire size OPEL CALIBRA 1988 Service Repair Manual

4Where applicable, the only test of the
catalytic converter’s efficiency is to check the
level of CO in the exhaust gas. This is
measured at the tailpipe with the engine
running (with no load) at 3000 rpm. If the CO
level exceeds the specified value, the Vauxhall
test equipment must be used to check the
entire fuel injection/ignition system. If the
engine is mechanically sound, once the
system has been eliminated, the fault must lie
in the converter, which must be renewed.
Motronic systems
Checking
5In order to check the idle mixture adjustment,
the following conditions must be met:
a)The engine must be at normal operating
temperature
b)All electrical consumers (cooling fan,
heater blower, headlamps etc.) must be
switched off
c)The spark plug gaps must be correctly
adjusted see Chapter 1
d)The throttle cable free play must be
correctly adjusted - see Section 19
e)The air inlet trunking must be free from
leaks, and the air filter must be clean
Adjustment
6Connect a tachometer and an exhaust gas
analyser to the vehicle in accordance with the
equipment manufacturer’s instructions.
7Start the engine and turn it at 2000 rpm for
approximately 30 seconds, then allow it to
idle. Check that the idle speed is within the
specified limits. No adjustment of idle speed
is possible, and if outside the specified limits,
the problem should be referred to a dealer.
8With the idle speed correct, check the CO
level in the exhaust gas. If it is outside the
specified limits, adjust by means of the idle
mixture adjustment screw in the airflow meter
or air mass meter, as applicable. In
production, the screw is covered by a
tamperproof plug; ensure that no local or
national laws are being broken before
removing the plug.9If the cooling fan cuts in during the
adjustment procedure, stop the adjustments,
and proceed when the cooling fan stops.
10When the idle mixture is correctly set,
stop the engine and disconnect the test
equipment.
Simtec systems
11Adjustment is not possible on these
models.
21Fuel pressure regulator -
removal and refitting
3
Note:Refer to Section 2 before proceeding
Removal
SOHC models (except Multec systems)
1Disconnect the battery negative lead.
2For improved access, remove the idle
speed adjuster as described in Section 22.
Disconnect the wiring harness housing from
the fuel injectors and move it to one side,
taking care not to strain the wiring. Pull up on
the wiring harness housing, and compress the
wiring plug retaining clips to release the
harness housing from the injectors.
3Position a wad of rag beneath the pressure
regulator, to absorb the fuel that will be
released as the regulator is removed.
4Loosen the clamp screws and disconnect
the fuel hoses from the regulator. Be prepared
for fuel spillage, and take adequate fire
precautions.
5Disconnect the vacuum pipe from the top
of the pressure regulator and withdraw the
regulator.
SOHC models (with Multec system)
6Depressurise the fuel system, as described
in Section 8.
7Remove the air box. Refer to Section 5, if
necessary.
8Disconnect the battery earth lead.9Noting the dowels locating the cover,
carefully unscrew the fuel pressure regulator
cover Torx-type screws (size TX 15). Ensure
that the spring does not fly out as the cover is
released. Remove the cover spring seat,
spring and diaphragm, noting how each is
fitted (see illustration).
10The diaphragm must be renewed
whenever the cover is disturbed. If any of the
regulator’s other components are worn or
damaged, they can be renewed only as part
of the throttle body upper section assembly.
DOHC models
11Disconnect the battery negative lead.
12Disconnect the wiring plug from the air
mass meter. Recover the sealing ring.
13Loosen the clamp screw securing the air
trunking to the right-hand end of the air mass
meter.
14Using an Allen key or hexagon bit,
unscrew the four bolts securing the air box to
the throttle body. Lift the air box from the
throttle body and disconnect the hose from
the base of the air box, then withdraw the air
box/air mass meter assembly.
15Disconnect the two breather hoses from
the rear of the camshaft cover, and move
them to one side.
16Disconnect the wiring plug from the
throttle position sensor.
17Disconnect the vacuum pipe from the top
of the pressure regulator (see illustration).
18Position a wad of rag beneath the
regulator, to absorb the fuel that will be
released as the regulator is removed.
19Using a spanner or socket, and working
underneath the regulator, unscrew the four
Torx type securing bolts, then withdraw the
regulator. Be prepared for fuel spillage, and
take adequate fire precautions.
Refitting
20Refitting is a reversal of removal, ensuring
that all wires, pipes and hoses are correctly
reconnected. Note that on DOHC models, the
4B•10Fuel and exhaust systems - fuel injection models
21.17 Fuel pressure regulator (arrowed) - DOHC model21.9 Fuel pressure regulator cover
A Locating dowels B Mounting screws

MOTTest Checks REF•11
MExamine the handbrake mechanism,
checking for frayed or broken cables,
excessive corrosion, or wear or insecurity of
the linkage. Check that the mechanism works
on each relevant wheel, and releases fully,
without binding.
MIt is not possible to test brake efficiency
without special equipment, but a road test can
be carried out later to check that the vehicle
pulls up in a straight line.
Fuel and exhaust systems
MInspect the fuel tank (including the filler
cap), fuel pipes, hoses and unions. All
components must be secure and free from
leaks.
MExamine the exhaust system over its entire
length, checking for any damaged, broken or
missing mountings, security of the retaining
clamps and rust or corrosion.
Wheels and tyres
MExamine the sidewalls and tread area of
each tyre in turn. Check for cuts, tears, lumps,
bulges, separation of the tread, and exposure
of the ply or cord due to wear or damage.
Check that the tyre bead is correctly seated
on the wheel rim, that the valve is sound andproperly seated, and that the wheel is not
distorted or damaged.
MCheck that the tyres are of the correct size
for the vehicle, that they are of the same size
and type on each axle, and that the pressures
are correct.
MCheck the tyre tread depth. The legal
minimum at the time of writing is 1.6 mm over
at least three-quarters of the tread width.
Abnormal tread wear may indicate incorrect
front wheel alignment.
Body corrosion
MCheck the condition of the entire vehicle
structure for signs of corrosion in load-bearing
areas. (These include chassis box sections,
side sills, cross-members, pillars, and all
suspension, steering, braking system and
seat belt mountings and anchorages.) Any
corrosion which has seriously reduced the
thickness of a load-bearing area is likely to
cause the vehicle to fail. In this case
professional repairs are likely to be needed.
MDamage or corrosion which causes sharp
or otherwise dangerous edges to be exposed
will also cause the vehicle to fail.
Petrol models
MHave the engine at normal operating
temperature, and make sure that it is in good
tune (ignition system in good order, air filter
element clean, etc).
MBefore any measurements are carried out,
raise the engine speed to around 2500 rpm,
and hold it at this speed for 20 seconds. Allowthe engine speed to return to idle, and watch
for smoke emissions from the exhaust
tailpipe. If the idle speed is obviously much
too high, or if dense blue or clearly-visible
black smoke comes from the tailpipe for more
than 5 seconds, the vehicle will fail. As a rule
of thumb, blue smoke signifies oil being burnt
(engine wear) while black smoke signifies
unburnt fuel (dirty air cleaner element, or other
carburettor or fuel system fault).
MAn exhaust gas analyser capable of
measuring carbon monoxide (CO) and
hydrocarbons (HC) is now needed. If such an
instrument cannot be hired or borrowed, a
local garage may agree to perform the check
for a small fee.
CO emissions (mixture)
MAt the time of writing, the maximum CO
level at idle is 3.5% for vehicles first used after
August 1986 and 4.5% for older vehicles.
From January 1996 a much tighter limit
(around 0.5%) applies to catalyst-equipped
vehicles first used from August 1992. If the
CO level cannot be reduced far enough to
pass the test (and the fuel and ignition
systems are otherwise in good condition) then
the carburettor is badly worn, or there is some
problem in the fuel injection system or
catalytic converter (as applicable).
HC emissionsMWith the CO emissions within limits, HC
emissions must be no more than 1200 ppm
(parts per million). If the vehicle fails this test
at idle, it can be re-tested at around 2000 rpm;
if the HC level is then 1200 ppm or less, this
counts as a pass.
MExcessive HC emissions can be caused by
oil being burnt, but they are more likely to be
due to unburnt fuel.
Diesel models
MThe only emission test applicable to Diesel
engines is the measuring of exhaust smoke
density. The test involves accelerating the
engine several times to its maximum
unloaded speed.
Note: It is of the utmost importance that the
engine timing belt is in good condition before
the test is carried out.
M
Excessive smoke can be caused by a dirty
air cleaner element. Otherwise, professional
advice may be needed to find the cause.
4Checks carried out on
YOUR VEHICLE’S EXHAUST
EMISSION SYSTEM
REF

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