compression ratio FORD SIERRA 1990 2.G Reference Workshop Manual

headings denoting various components or systems, such as Engine,
Cooling system, etc. The Chapter and/or Section which deals with the
problem is also shown in brackets. Whatever the fault, certain basic
principles apply. These are as follows:
Verify the fault. This is simply a matter of being sure that you know
what the symptoms are before starting work. This is particularly
important if you are investigating a fault for someone else, who may
not have described it very accurately.
Don’t overlook the obvious. For example, if the vehicle won’t start, is
there fuel in the tank? (Don’t take anyone else’s word on this particular
point, and don’t trust the fuel gauge either!) If an electrical fault is
indicated, look for loose or broken wires before digging out the test
gear.Cure the disease, not the symptom. Substituting a flat battery with a
fully-charged one will get you off the hard shoulder, but if the
underlying cause is not attended to, the new battery will go the same
way. Similarly, changing oil-fouled spark plugs for a new set will get
you moving again, but remember that the reason for the fouling (if it
wasn’t simply an incorrect grade of plug) will have to be established
and corrected.
Don’t take anything for granted. Particularly, don’t forget that a
“new” component may itself be defective (especially if it’s been rattling
around in the boot for months), and don’t leave components out of a
fault diagnosis sequence just because they are new or recently-fitted.
When you do finally diagnose a difficult fault, you’ll probably realise
that all the evidence was there from the start.
Engine fails to rotate when attempting to start
MBattery terminal connections loose or corroded (Chapter 1).
MBattery discharged or faulty (Chapter 5).
MBroken, loose or disconnected wiring in the starting circuit (Chapter 5).
MDefective starter solenoid or switch (Chapter 5).
MDefective starter motor (Chapter 5).
MStarter pinion or flywheel/driveplate ring gear teeth loose or broken
(Chapters 2 or 5).
MEngine earth strap broken or disconnected.
Starter motor turns engine slowly
MPartially-discharged battery (recharge, use jump leads, or push start)
(Chapter 5).
MBattery terminals loose or corroded (Chapter 1).
MBattery earth to body defective (Chapter 5).
MEngine earth strap loose.
MStarter motor (or solenoid) wiring loose (Chapter 5).
MStarter motor internal fault (Chapter 5).
Engine rotates, but will not start
MFuel pump inertia switch tripped (electric pump) (Chapter 4).
MFuel tank empty.
MBattery discharged (engine rotates slowly) (Chapter 5).
MBattery terminal connections loose or corroded (Chapter 1).
MIgnition components damp or damaged (Chapters 1 and 5).
MBroken, loose or disconnected wiring in the ignition circuit (Chapters 1
and 5).
MWorn, faulty or incorrectly-gapped spark plugs (Chapter 1).
MFuel injection system fault (Chapter 4).
MMajor mechanical failure (eg broken timing chain) (Chapter 2).
Engine difficult to start when cold
MBattery discharged (Chapter 5).
MBattery terminal connections loose or corroded (Chapter 1).
MWorn, faulty or incorrectly-gapped spark plugs (Chapter 1).
MFuel injection system fault (Chapter 4).
MOther ignition system fault (Chapters 1 and 5).
MLow cylinder compressions (Chapter 2).
Engine difficult to start when hot
MAir filter element dirty or clogged (Chapter 1).
MFuel injection system fault (Chapter 4).
MLow cylinder compressions (Chapter 2).
Starter motor noisy or excessively-rough in
engagement
MStarter pinion or flywheel/driveplate ring gear teeth loose or broken
(Chapters 2 or 5).
MStarter motor mounting bolts loose or missing (Chapter 5).
MStarter motor internal components worn or damaged (Chapter 5).
Engine starts, but stops immediately
MLoose or faulty electrical connections in the ignition circuit
(Chapters 1 and 5).
MVacuum leak at the throttle body or inlet manifold (Chapter 4).
MFuel injection system fault (Chapter 4).
Engine idles erratically
MIncorrectly-adjusted idle speed (Chapter 4).
MAir filter element clogged (Chapter 1).
MVacuum leak at the throttle body, inlet manifold or associated
hoses (Chapter 4).
MWorn, faulty or incorrectly-gapped spark plugs (Chapter 1).
MUneven or low cylinder compressions (Chapter 2).
MCamshaft lobes worn (Chapter 2).
MFuel injection system fault (Chapter 4).
Engine misfires at idle speed
MWorn, faulty or incorrectly-gapped spark plugs (Chapter 1).
MFaulty spark plug HT leads (Chapter 5).
MVacuum leak at the throttle body, inlet manifold or associated
hoses (Chapter 4).
MFuel injection system fault (Chapter 4).
MDistributor cap cracked or tracking internally, where applicable
(Chapter 5).
MUneven or low cylinder compressions (Chapter 2).
MDisconnected, leaking, or perished crankcase ventilation hoses
(Chapter 4).
Engine misfires throughout the driving speed range
MFuel filter choked (Chapter 1).
MFuel pump faulty, or delivery pressure low (Chapter 4).
MFuel tank vent blocked, or fuel pipes restricted (Chapter 4).
MVacuum leak at the throttle body, inlet manifold or associated
hoses (Chapter 4).
MWorn, faulty or incorrectly-gapped spark plugs (Chapter 1).
MFaulty spark plug HT leads (Chapter 5).
MDistributor cap cracked or tracking internally, where applicable
(Chapter 5).
MFaulty ignition coil (Chapter 5).
MUneven or low cylinder compressions (Chapter 2).
MFuel injection system fault (Chapter 4).
Engine hesitates on acceleration
MWorn, faulty or incorrectly-gapped spark plugs (Chapter 1).
MVacuum leak at the throttle body, inlet manifold or associated
hoses (Chapter 4).
MFuel injection system fault (Chapter 4).
Engine stalls
MVacuum leak at the throttle body, inlet manifold or associated
hoses (Chapter 4).
REF•12Fault diagnosis
Engine

MFuel filter choked (Chapter 1).
MFuel pump faulty, or delivery pressure low (Chapter 4).
MFuel tank vent blocked, or fuel pipes restricted (Chapter 4).
MFuel injection system fault (Chapter 4).
Engine lacks power
MFuel filter choked (Chapter 1).
MFuel pump faulty, or delivery pressure low (Chapter 4).
MUneven or low cylinder compressions (Chapter 2).
MWorn, faulty or incorrectly-gapped spark plugs (Chapter 1).
MVacuum leak at the throttle body, inlet manifold or associated
hoses (Chapter 4).
MFuel injection system fault (Chapter 4).
MBrakes binding (Chapters 1 and 10).
MClutch slipping (Chapter 6).
Engine backfires
MVacuum leak at the throttle body, inlet manifold or associated
hoses (Chapter 4).
MFuel injection system fault (Chapter 4).
Oil pressure warning light illuminated with engine
running
MLow oil level, or incorrect oil grade (Chapter 1).
MFaulty oil pressure sensor (Chapter 2).
MWorn engine bearings and/or oil pump (Chapter 2).
MExcessively high engine operating temperature (Chapter 3).
MOil pressure relief valve defective (Chapter 2).
MOil pick-up strainer clogged (Chapter 2).
Note:Low oil pressure in a high-mileage engine at tickover is not
necessarily a cause for concern. Sudden pressure loss at speed is far
more significant. In any event, check the gauge or warning light sender
before condemning the engine.
Engine runs-on after switching off
MExcessive carbon build-up in engine (Chapter 2).
MExcessively high engine operating temperature (Chapter 3).
Engine noises
Pre-ignition (pinking) or knocking during acceleration or
under load
MIgnition timing incorrect/ignition system fault (Chapters 1 and 5).
MIncorrect grade of spark plug (Chapter 1).
MIncorrect grade of fuel (Chapter 1).
MVacuum leak at throttle body, inlet manifold or associated hoses
(Chapter 4).
MExcessive carbon build-up in engine (Chapter 2).
MFuel injection system fault (Chapter 4).
Whistling or wheezing noises
MLeaking inlet manifold or throttle body gasket (Chapter 4).
MLeaking exhaust manifold gasket (Chapter 4).
MLeaking vacuum hose (Chapters 4 and 10).
MBlowing cylinder head gasket (Chapter 2).
Tapping or rattling noises
MWorn valve gear, timing chain, camshaft or hydraulic tappets
(Chapter 2).
MAncillary component fault (water pump, alternator, etc) (Chapters 3, 5)
Knocking or thumping noises
MWorn big-end bearings (regular heavy knocking, perhaps less
under load) (Chapter 2).
MWorn main bearings (rumbling and knocking, perhaps worsening
under load) (Chapter 2).
MPiston slap (most noticeable when cold) (Chapter 2).
MAncillary component fault (water pump, alternator, etc) (Chapters 3, 5)
Overheating
MAuxiliary drivebelt broken or incorrectly adjusted (Chapter 1).
MInsufficient coolant in system (Chapter 1).
MThermostat faulty (Chapter 3).
MRadiator core blocked, or grille restricted (Chapter 3).
MElectric cooling fan or thermostatic switch faulty (Chapter 3).
MViscous-coupled fan faulty (Chapter 3).
MIgnition timing incorrect, or ignition system fault (Chapters 1 and 5).
MInaccurate temperature gauge sender unit (Chapter 3).
MAirlock in cooling system (Chapter 3).
Overcooling
MThermostat faulty (Chapter 3).
MInaccurate temperature gauge sender unit (Chapter 3).
External coolant leakage
MDeteriorated or damaged hoses or hose clips (Chapter 1).
MRadiator core or heater matrix leaking (Chapter 3).
MPressure cap faulty (Chapter 3).
MWater pump internal seal leaking (Chapter 3).
MWater pump-to-block seal leaking (Chapter 3).
MBoiling due to overheating (Chapter 3).
MCore plug leaking (Chapter 2).
Internal coolant leakage
MLeaking cylinder head gasket (Chapter 2).
MCracked cylinder head or cylinder block (Chapter 2).
Corrosion
MInfrequent draining and flushing (Chapter 1).
MIncorrect coolant mixture or inappropriate coolant type (Chapter 1).
Fault diagnosisREF•13
REF
Cooling system
Excessive fuel consumption
MAir filter element dirty or clogged (Chapter 1).
MFuel injection system fault (Chapter 4).
MIgnition timing incorrect or ignition system fault (Chapters 1 and 5).
MBrakes binding (Chapter 10).
MTyres under-inflated (Chapter 1).
Fuel leakage and/or fuel odour
MDamaged fuel tank, pipes or connections (Chapters 1 and 4).
Excessive noise or fumes from exhaust system
MLeaking exhaust system or manifold joints (Chapters 1 and 4).
MLeaking, corroded or damaged silencers or pipe (Chapters 1 and 4).
MBroken mountings causing body or suspension contact (Chapter 4).
Fuel and exhaust systems

Glossary of Technical termsREF•19
REF
CamshaftA rotating shaft on which a series
of cam lobes operate the valve mechanisms.
The camshaft may be driven by gears, by
sprockets and chain or by sprockets and a
belt.
CanisterA container in an evaporative
emission control system; contains activated
charcoal granules to trap vapours from the
fuel system.
CarburettorA device which mixes fuel with
air in the proper proportions to provide a
desired power output from a spark ignition
internal combustion engine.
CastellatedResembling the parapets along
the top of a castle wall. For example, a
castellated balljoint stud nut.
CastorIn wheel alignment, the backward or
forward tilt of the steering axis. Castor is
positive when the steering axis is inclined
rearward at the top.Catalytic converterA silencer-like device in
the exhaust system which converts certain
pollutants in the exhaust gases into less
harmful substances.
CirclipA ring-shaped clip used to prevent
endwise movement of cylindrical parts and
shafts. An internal circlip is installed in a
groove in a housing; an external circlip fits into
a groove on the outside of a cylindrical piece
such as a shaft.
ClearanceThe amount of space between
two parts. For example, between a piston and
a cylinder, between a bearing and a journal,
etc.
Coil springA spiral of elastic steel found in
various sizes throughout a vehicle, for
example as a springing medium in the
suspension and in the valve train.
CompressionReduction in volume, and
increase in pressure and temperature, of a
gas, caused by squeezing it into a smaller
space.
Compression ratioThe relationship between
cylinder volume when the piston is at top
dead centre and cylinder volume when the
piston is at bottom dead centre.
Constant velocity (CV) jointA type of
universal joint that cancels out vibrations
caused by driving power being transmitted
through an angle.
Core plugA disc or cup-shaped metal device
inserted in a hole in a casting through which
core was removed when the casting was
formed. Also known as a freeze plug or
expansion plug.
CrankcaseThe lower part of the engine
block in which the crankshaft rotates.
CrankshaftThe main rotating member, or
shaft, running the length of the crankcase,
with offset “throws” to which the connecting
rods are attached.Crocodile clipSee Alligator clip
DDiagnostic codeCode numbers obtained by
accessing the diagnostic mode of an engine
management computer. This code can be
used to determine the area in the system
where a malfunction may be located.
Disc brakeA brake design incorporating a
rotating disc onto which brake pads are
squeezed. The resulting friction converts the
energy of a moving vehicle into heat.
Double-overhead cam (DOHC)An engine
that uses two overhead camshafts, usually
one for the intake valves and one for the
exhaust valves.
Drivebelt(s)The belt(s) used to drive
accessories such as the alternator, water
pump, power steering pump, air conditioning
compressor, etc. off the crankshaft pulley.
DriveshaftAny shaft used to transmit
motion. Commonly used when referring to the
axleshafts on a front wheel drive vehicle.
Drum brakeA type of brake using a drum-
shaped metal cylinder attached to the inner
surface of the wheel. When the brake pedal is
pressed, curved brake shoes with friction
linings press against the inside of the drum to
slow or stop the vehicle.
Castellated nut
Catalytic converter
Crankshaft assembly
Carburettor
Canister
Drum brake assembly
Accessory drivebelts
Driveshaft

AAccelerator cable- 4A•8
Accelerator pedal- 4A•8
Acknowledgements- 0•4
Aerial- 13•20
Air cleaner- 1•18, 1•19, 4A•4, 4B•4
Air conditioning systems- 1•16, 3•1 et seq
Airflow meter- 4B•8
Alarm system- 13•19
Alternator- 5•6
Anti-roll bars- 11•6, 11•13
Anti-theft alarm- 13•19
Antifreeze- 0•17, 1•21, 3•3
ATF- 0•17, 1•3
Automatic transmission- 7B•1 et seq
extension housing oil seal - 7B•5
fault diagnosis - REF•11, REF•14
fluid - 0•17, 1•3
fluid checks - 1•13
gear selector mechanism - 7B•5
kickdown cable - 7B•3
removal and refitting - 7B•2
reversing lamp switch - 7B•6
selector rod - 7B•5
starter inhibitor switch - 7B•6
vacuum diaphragm unit - 7B•6
Auxiliary drivebelts- 1•14, 1•21
Auxiliary shaft- 2A•18
BBattery- 0•15, 1•15, 5•5
Bearings (engine) - 2A•23, 2B•17, 2C•23
Bleeding the power steering- 11•18
Bleeding the brakes- 10•2
Body damage- 12•2, 12•4
Body electrical systems - 13•1 et seq
Bodywork and fittings- 12•1 et seq
Bonnet release cable- 12•4
Bonnet lock- 12•4, 12•5
Boot lid lock- 12•5
Brake checks- 1•10
Brake fluid- 0•13, 0•1, 1•21
Braking system- 10•1 et seq
backplate - 10•12
bleeding the brakes - 10•2
brake caliper - 10•8, 10•10
brake disc - 10•3, 10•11
brake drum - 10•12
brake fluid pipes and hoses - 10•19
brake fluid reservoir - 10•15
brake lamp switch - 13•6
brake pads - 10•3
brake pedal - 10•22
brake shoes - 10•6
computer module (ABS) - 10•17
deceleration valve - 10•18
fault diagnosis - REF•11, REF•15
handbrake adjustment - 1•16, 10•20, 10•21
handbrake cables - 1•16, 10•20, 10•21
handbrake lever - 10•22
hoses brake - 10•19
hydraulic unit pressure switch - 10•17
hydraulic unit/pump/motor (ABS) - 10•15, 10•16
load apportioning valve - 10•19master cylinder (brake) - 10•13
pressure switch - 10•17
vacuum servo unit - 10•14
valve block (ABS) - 10•17
wheel cylinder - 10•12
wheel sensor - 10•18
Bulbs exterior- 13•16
Bulbs interior- 13•10
Bulbs ratings- 13•2
Bumpers- 12•13
Buying spare parts - REF•3
CCables:
accelerator - 4A•8
bonnet release - 12•4
clutch - 6•2
handbrake - 10•20, 10•21
kickdown - 7B•3
speedometer - 13•11
tailgate/boot lid/filler cap - 12•6
Caliper (brake) front/rear- 10•8, 10•10
Camshaft and followers- 2A•17, 2B•14, 2C•16
Capacities- 1•3
Carburettor:
Ford VV type - 1•12, 4A•8, 4A•13
Pierburg 2V type - 1•12, 4A•8, 4A•14
Weber 2V type - 1•12, 4A•8, 4A•14
Weber 2V TLD type - 1•12, 4A•8, 4A•15
Cargo area- 12•10
Carpets- 12•2
Catalytic converter- 4B•3, 4B•14
Central locking system- 13•18
Centre/overhead console- 12•18, 12•19
CFI unit- 4B•10
Charging system- 5•5
Cigarette lighter- 13•6
Clock- 13•6
Clutch- 6•1 et seq
assembly - 6•3
cable - 6•2
fault diagnosis - REF•11, REF•14
pedal - 6•2
release bearing - 6•5
Coil- 5•13
Coil spring (rear) - 11•10
Compression test- 2A•7
Computer module (ABS)- 10•17
Connecting rods- 2A•22, 2B•17, 2C•21
Contents- 0•2
Coolant- 0•12, 0•17, 1•21, 3•3
Coolant level- 0•12
Cooling, heating and air conditioning
systems- 3•1 et seq
antifreeze - 0•12, 0•17, 1•21, 3•3
coolant pump - 3•5
coolant temperature sender and sensor - 3•8
cooling fan - 3•7
draining - 1•21
drivebelt tensioner - 3•7
expansion tank/coolant sensor - 3•8
fan (radiator) - 3•7
fault diagnosis - REF•11, REF•13
filling - 1•21
flushing - 1•21heater - 3•9
radiator - 3•3
switches - 3•8
temperature gauge and sender unit - 3•8
thermostat - 3•4
Courtesy lamp switch- 13•5
Crankshaft oil seals- 2A•19, 2B•15, 2C•19
Crankshaft bearings- 2A•23, 2B•17, 2C•23
Cylinder bores- 2A•24
Cylinder head- 2A•14, 2B•10, 2C•13
DDents- 12•2
Depressurising fuel injection system- 4B•4
Dimensions and weights- REF•1
Disc brake - 10•3, 10•11
Distributor- 5•14, 5•15, 5•16
Door- 12•6
Door inner trim panel- 12•7
Door mirror switch- 13•5
Drivebelts check- 1•14, 1•21, 3•7
Driveplate- 2A•18, 2B•15, 2C•19
Driveshafts:
check - 1•17
fault diagnosis - REF•11, REF•15
overhaul - 9•5
removal and refitting - 9•4
Drum (brake)- 10•12
EEarth fault finding- 13•3
Electric windows- 13•18
Electrical fault finding- 13•2
Electrical system (body)- 13•1 et seq
Electrical system:
weekly checks - 0•14
fault diagnosis - REF•11, REF•16
Electronic vacuum regulator- 4B•11
Engine:
auxiliary shaft - 2A•18
bearings - 2A•23, 2B•17, 2C•23
bores - 2A•24
camshaft followers - 2A•17, 2B•14, 2C•16
codes - 2A•1, 2B•1, 2C•1
compartment views - 0•10, 1•5
compression test - 2A•7
connecting rods - 2A•22, 2B•17, 2C•21
crankshaft bearings - 2A•23, 2B•17, 2C•23
crankshaft oil seals - 2A•19, 2B•15, 2C•19
cylinder bores - 2A•24
cylinder head - 2A•14, 2B•10, 2C•13
dismantling - 2A•11, 2B•8, 2C•10
DOHC engines- 2B•1 et seq
driveplate - 2A•18, 2B•15, 2C•19
fault diagnosis - REF•11, REF•12
flywheel - 2A•18, 2B•15, 2C•19
main bearings - 2A•23, 2B•17, 2C•23
mountings - 2A•11, 2B•7, 2C•9
oils - 0•17, 1•3
oil and filter renewal - 1•9
oil level - 0•12
oil pump - 2A•21, 2B•16, 2C•20
oil seals crankshaft - 2A•19, 2B•15, 2C•19
piston - 2A•22, 2B•17, 2C•21
IndexREF•23
REF
Note: References throughout this index are in the form - “Chapter number” • “page number”