1999 FIAT PUNTO Petrol

Every 20 000 miles - petrol models 1A.13
20 Ignition system check
81
21 Engine management system check

A


Warning: Voltages produced by an electronic ignition system are considerably higher than those produced by conventional ignition systems. Extreme care must be taken when working on the system with the Ignition switched on. Persons with surgically-Implanted cardiac pacemaker devices should keep well clear of the ignition circuits, components and test oquipment. 1 The ignition system components should be checked for damage or deterioration as follows.
General component check 2 The spark plug (HT) leads should be checked whenever new spark plugs are fitted. 3 Pull the leads from the plugs by gripping
the end
fitting, not the lead, otherwise the lead connection may be fractured.
Ensure that the leads are i numbered before removing i them, to avoid confusion when refitting
4 Check Inside the end fitting for signs of corrosion, which will look like a white crusty powder. Push the end fitting back onto the spark plug, ensuring that it is a tight fit on the plug. if not, remove the lead again and use pliers to carefully crimp the metal connector inside the end fitting until it fits securely on the
end
of the spark plug. 5 Using a clean rag, wipe Ihe emlre length of the lead to remove any built-up dirt and grease. Once the lead is clean, check for bums, cracks and other damage. Do not bend the lead excessively, nor pull the lead lengthways - the conductor inside might break. 6 Disconnect the other end of the lead from the ignition coll. Again, pull only on the end fitting. Check for corrosion and a tight fit in the
same
manner as the spark plug end. Refit the bad securely on completion. 7 Check the remaining leads one at a time, in
ihe same
way. 8 if new spark plug (HT) leads are required, purchase a set for your specific car and engine. 9 Even with the ignition system In first-class condition, some engines may still occasionally experience poor starting attributable to damp ignition components. To disperse moisture, a water-dispersant aerosol should be liberally
Ignition timing -
check
and adjustment 10 Check the ignition timing as described In Chapter 58.
1 This check is part of the manufacturer's maintenance schedule, and Involves testing Ihe engine management system using special dedicated test equipment. Such testing will allow the test equipment to read any fault codes stored in the electronic control unit memory. 2 Unless a fault is suspected, this test te not essential, although it should be noted that it is recommended by the manufacturers. 3 If access to suitable test equipment is not possible, make a thorough check of all ignition, fuel and emission control system components, hoses, and wiring, for security and obvious signs of damage. Further details of the fuet system, emission control system and ignition system can be .found In the relevant parts of Chapters 4 and 5.
22 Hinge and lock lubrication %
1
1 Lubricate the hinges of the bonnet, doors and tailgate with a light general-purpose oil. Similarly, lubricate ail latches, locks and lock strikers. At the same time, check the security and operation of all the locks, adjusting them If necessary (see Chapter 11). 2 Lightly lubricate the bonnet release mechanism and cable with a suitable grease.
23 Headlight beam adjustment % & ^
1 Accurate adjustment of the headlight beam is only possible using optical beem-setting equipment, and this work should therefore be carried out by a Fiat dealer or service station with the necessary facilities. In an emergency, however, the following procedure will provide an acceptable light pattern. 2 Position the car on a level surface with tyres correctly inflated, approximately 10 metres in front of. and at right-angles to, a wall or garage door, 3 Draw a horizontal line on the wall or door at headlamp centre height. Draw a vertical line corresponding to the centre line of the car, then measure off a point either side of this, on the horizontal line, corresponding with the headlamp centres. 4 Switch on the main beam and check that the areas of maximum illumination coincide with the headlamp centre marfcs on Ihe wall, if not. turn the adjustment screw located on the upper inside edge of the headlight unit to adjust the beam laterally, and the adjustment screw located on the upper outside edge of the headlight unit to adjust the beam
vertically. On models with electric headlight adjustment, make sure that it is set at its basic setting before making the adjustment.
24 Road test
Instruments and electrical equipment 1 Check the operation of all Instruments and electrical equipment. 2 Make sure that all instruments read correctly, and switch on all electrical equipment in turn, to check that it functions properly.
Steering and suspension 3 Check for any abnormalities in the steering, suspension, handling or road feel. 4 Drive the vehicle, and check that there are no unusual vibrations or noises. 5 Check that the steering feels positive, with no excessive sloppiness, or roughness, and check for any suspension noises when cornering and driving over bumps.
Drivetrain 6 Check the performance of the engine, clutch (where applicable), transmission and driveshafts. 7 Listen for any unusual noises from the engine, clutch and gearbox/transmission. 8 Make sure that the engine runs smoothly when Idling, and that there Is no hesitation when accelerating. 9 Check that, where applicable, the clutch action Is smooth and progressive, that the drive is taken up smoothly, and that the pedal travel is not excessive. Also listen for any noises when the clutch pedal is depressed. 10 On manual gearbox models, check that all gears can be engaged smoothly without noise, and that the gear lever action is not abnormally vsgue or notchy. 11 On automatic transmission models, check that all Ihe gear positions can be selected with the vehicle at rest, if any problems are found, they should be referred to a Flat dealer. 12 Listen for a metallic clicking sound from the front of the vehicle, as the vehicle is driven slowly in a circle with the steering on full-lock. Carry out this check in both directions. If a clicking noise is heard, this Indicates wear in a drtveshaft joint, In which case renew the joint if necessary.
Check the braking system 13 Make sure that the vehicle does not pull to one side when braking, and that the wheels do not lock prematurely when braking hard. 14 Check that there is no vibration through the steering when braking. 15 Check that the handbrake operates correctly without excessive movement of the lever, and that It holds the vehicle stationary on a slope.

ia.14 Every 20 000 miles - petrol models
16 Test the operation of the brake servo unit as follows. With the engine off, depress the footbrake four or five times to exhaust the vacuum. Hold the brake pedal depressed, then start the engine. As the engine starts.
there should be a noticeable give In the brake pedal as vacuum builds up. Allow the engine to run for at least tsvo minutes, and then switch it off. If the brake pedal is depressed now. it should be possible to detect a hiss
from the servo as the pedal is depressed. After about four or five applications, no further hissing should be heard, and the pedal shouto feel considerably harder.
Every 30 000 miles (45 000 km) or 3 years
. transmission (see illustration). Using an Allen 25 Lambda/oxygen sensor ^ key, unscrew the plug and clean it. check \ 3 The oil level should reach the lower edge of ^ the filler/level hole. A certain amount of oil will have gathered behind the filler/level plug, and If the CO level at the exhaust tailpipe is too w,u tr,cWe out when is 'e™oved; this does high or low, Ihe vehicle should be taken to a «©l necessarily Indicate that the level is Fiat dealer so lhat the complete fuel-injection correct. To ensure that a true level is and ignition systems, including the Lamoda/ established, wait until the Initial trickle has oxygen sensor, can be thoroughly checked stopped, then ado oil as necessary until a using the special diagnostic equipment. Once ,r,ckle o1 new oil can be seen emerging. The these have been checked and are known to 'W wl" be correct when ,he flow ceases-us® be free from faults, the fault must be in the good-quality oil of the specified type, catalytic converter, which must be renewed Make sur®that vehicle Is completely level as described In Chapter 4D, Section 6. checking the level and do not overfill, 4 When the level Is correct refit and tighten the plug and wipe away any spilt oil.
26 Manual transmission oil level check ^ 27 Evaporative loss system ^ check
1 Park Ihe vehicle on a level surface, If possible over an inspection pit or on a ramp as the filler/level plug is best reached from under Ihe engine compartment. The oil level must be checked before the car is driven, or at least 5 minutes after the engine has been switched off. If the oil ts checked Immediately alter driving the car, some of the oil will remain distributed around the transmission components, resulting in an inaccurate level reading. 2 Wipe clean the area around the filler/level plug, which is situated on the front of the
Refer to Chapter 40 Section 2 and check that all wiring and hoses are correctly connected to the evaporative toss system components.
28 Automatic transmission fitter and fluid change
1 Take the vehicle on a short run. to warm the transmission up to operating temperature.
Park the car on level ground, then switch off the Ignition. 2 Firmly apply the handbrake, then jack up the front of the car and support It securely on axle stands (see Jacking and vehicle support]. Note thai, when refilling and checking Uie fluid level, the car must be lowered to the ground, and level, to ensure accuracy. 3 Remove the dipstick, then position a suitable container under the transmission, Unscrew the sump drain plug and allow the fluid to drain for at ieast 10 minutes. Refit and tighten the drain plug when the fluid has completely drained.

A


Warning: The transmission fluid may be very hot and precautions must be taken to avoid scalding.
4 Clean around the transmission sump mating flange. Unboll and remove the sump and remove the gasket. 5 Remove the two bolts and withdraw the transmission fluid filter {see illustration). 6 Fit the new filter, and secure It with the two bolts. 7 Refit the sump using a new gasket, then
_
lower the vehicle to the ground, 8 Fill the transmission with the specified quantity of fluid via Ihe dipstick tube, using a funnel with a fine mesh filter. 9 Run the engine to normal operating temperature, then check the fluid level as described In Weekly checks. 10 Dispose of the old fluid safely.
26.2 Transmission filler/level plug location 28.5 Automatic transmission fluid filter retaining bolts

Maintenance procedures - petrol models 1A.15
Every 40 000 miles (60 000 km) or 4 years
29 Rear brake shoe check
1 Chock the front wheels then Jack up the rear of Ihe car and support it on axle stands (see Jacking and Vehicle Support). Remove the rear roadwheels. 2 Using the inspection hole at the edge of the brake drum, check that the linings are not worn below Ihe minimum thickness given in the Specifications (see illustration). If necessary use a torch. 3 If the friction material on any shoe is worn down to the specified minimum thickness or
less,
all four shoes must be renewed as a set. 4 At the same time check for signs of brake
Kutti
leakage. 5 For a comprehensive check, the brake drum should be removed and cleaned. This
will allow the wheel cylinders to be checked, and the condition of the brake drum itself to be fully examined (see Chapter 9). 6 Refit the lubber plugs then lower the car to the ground.
30 Timing belt renewal
Refer to Chapter 2A or 2B. Note: Although the norma/ interval for timing belt renewal is 70 000 miles (105 000 km), it is strongly recommended that the interval Is reduced on vehicles which are subjected to intensive use. ie, mainly short journeys or a lot of stop-start driving. The actual belt renewal interval is therefore very much up to the individuaf owner. That being said, it is highly recommended to err on the side of safety, and
29.2 Check the thickness of the shoe friction material through the hole on the edge of the drum (arrowed)
renew the belt at 40 000 miles (60 000 km), bearing in mind the drastic consequences resulting from belt failure.
Every 60 000 miles (90 000 km) or 6 years
31 Emission control system check
Refer to Chapter 4D. A full check of the emissions control systems must be made by a Fiat dealer.
Every 80 000 miles (120 000 km)
32 Manual transmission all renewal S
1 Park the vehicle on a level surface, if possible over an inspection pit or on a ramp as the filler/level and drain plugs are accessed from order
the
engine compartment. If necessary
Jack
ip the vehicle and support on axle stands (see
Jacking and vehicle
support). 2 Wipe clean the area around the filler/leval And drain plugs, which are on the front and bottom of the transmission (see illustration).
3 Using an Allen key. unscrew the filler/level plug and clean it. 4 Position a suitable container beneath the transmission, then use the Allen key to unscrew the drain plug. Allow the oil to completely drain. 5 Wipe clean the drain plug then refit and tighten It. 6 Fill the transmission with ihe correct grade and quantity of oil, referring to Section 26 when checking the level. Refit and lighten the filler/level plug. 7 Where applicable lower the vehicle to the ground. 32.2 Transmission drain plug location (viewed from under the vehicle)
Every 2 years (regardless of mileage)
33 Coolant renewal
I
Cooling system draining

A


Warning: Walt until the engine Is cold before starting this pro-cedure. Do not allow antifreeze to come In contact with your skin, or with the painted surfaces of the vehicle. Rinse off spills immediately with plenty of water.
Ndver
leave antifreeze lying around In an open container, or fn a puddle In the
driveway or on the garage floor. Children and pets are attracted by its sweet smell, but ant/freeze can be fatal if ingested. 1 With the engine completely cold, cover the expansion tank cap with a wad of rag. and slowly turn the cap anticlockwise to relieve the pressure in the cooling system (a hissing sound will normally be heard). Wait until any pressure remaining in the system is released, then continue to tum the cap until it can be removed. 2 Position a suitable container beneath the radiator bottom hose connection, then release the retaining clip and ease the hose from the radiator stub (see illustration). If the hose 33.2 Disconnecting the radiator bottom hose to drain tho coolant

ia.16 Every 2 years - petrol models
joint has not been disturbed for some time, if will bo necessary to gently manipulate the hose to break the joint. Do not use excessive force, or the radiator stub could be damaged. Allow the coolant to drain Into the container. 3 Certain models are fitted with cooling system bleed plugs, which should be opened to aid the draining process and help prevent airlocks. These are located on the top right hand edge of the radiator, on the heater Inlet hose and additionally, on 16-valve engines, on the heater outlet hose (see illustrations). If the coolant has been drained for a reason other than renewal, then provided It is ciean and less than two years old, it can be re-used, though this is not recommended. 4 Once ail the coofant has drained, reconnect the hose to the radiator and secure it in position with the retaining clip.
Cooling system flushing 5 If coolant renewal has been neglected, or If the antifreeze mixture has become diluted, then in time, Ihe cooling system may gradually lose efficiency, as the coolant passages become restricted due to rust, scale deposits, and other sediment. The cooling system efficiency can be restored by flushing the system clean. 6 The radiator should be flushed Independently of the engine, to avoid contamination. Radiator flushing 7 To flush the radiator disconnect the top and bottom hoses and any other relevant hoses from the radiator, with reference to Chapter 3. 8 Insert a garden hose into the radiator top inlet. Direct a flow of clean v/ater through the radiator, and continue flushing until clean water emerges from the radiator bottom outlet. 9 If after a reasonable period, the water still does not run clear, the radiator can be flushed wilh a good propnetary cooling system
cleaning agent. It is important that their manufacturer's Instructions are followed carefully. If the contamination is particularly bad, insert the hose in the radiator bottom outlet, and reverse-flush the radiator. Engine flushing 10 To flush the engine, remove the thermostat as described In Chapter 3 then temporarily refit the thermostat cover. 11 With the top and bottom hoses disconnected from the radiator, insert a garden hose into the radiator top hose. Direct a clean flow of water through the engine, and continue flushing until clean water emerges from the radiator bottom hose. 12 On complotion of flushing, refit the thermostat and reconnect the hoses with reference to Chapter 3,
Cooling system filling 13 Before attempting to fill the cooling system, make sure that all hoses and clips are in good condition, and that the clips are tight. Note that an antifreezo mixture must be used all year round, to prevent corrosion of the engine components (see below). 14 Remove the expansion tank filler cap. and fill the system by slowly pouring the coolant Into the oxpansion lank to prevent airlocks from forming. Ensure that all bleed plugs/screws are open. 15 If the coolant Is being renewed, begin by pouring in a couple of litres of v/ater, followed by the correct quantity of antifreeze, then top-up with more water. 16 Once the level in the expansion tank starts to rise, squeeze the radiator top and bottom hoses to help expel any trapped air In the system. Once all the air is expelled, top-up the coolant level to the MAX mark and refit the expansion tank cap. Close all bleed plugs. Continue the filling procedure as follows according to engine type.
1108 cc and 1242 cc (8-vaive) engines 17 Start the engine and run it until tt reaches normal operating temperature, then stop the engine and allow it to cool. 18 Chock for teaks, particularly around disturbed components. Check the coolant level in the expansion tank, and top-up H necessary. Note that the system must be coW before an accurate level Is indicated in the oxpansion tank. If the expansion tank cap is removed while the engine Is still warm, cover Ihe cap with a thick cloth, and unscrew the cap slowly to gradually relieve the system pressure (a hissing sound will normally be heard). Wall until any pressure remaining In the system is released, then continue to turn the cap until It can be removed. 1242 cc (16-valve) engines 19 Remove the expansion tank filler cap. start the engine and run it at Idling speed for two to three minutes. Allow the engine to continue running until the electric cooling fan operates, but during this time, briefly in-crease the engine speed to 2000 to 3000 rpm every 30 seconds. Maintain the coolant level in the expansion tank to the MAX mark during tliis procedure, adding more coolant as necessary. 20 On models without air conditfoning, wilh the engine still idling, carefully unscrew the bleed plug on the top of the radiator. Increase the engine speed until fluid emerges from the bleed plug, then close the plug and return the engine to idle.

A


Warning: Take suitable pre-cautions against scalding when opening the bleed plug as the coolant will be very hot. 21 On all models, allow the engine to continue running at idle for a further five minutes. After this time, switch the engine ofl, allow it 1o cool completely and when cool

Every 2 years - petrol models ia.i?
check, and if necessary top-up, the level in the expansion tank. Refit the cap on completion. Antifreeze mixture 22 The antifreeze should always be renewed at the specified Intervals. This is necessary not only to maintain the antifreeze properties, but also to prevent corrosion which would otherwise occur as the corrosion inhibitors
beoome
progressively less effective. 23 Always use an ethylene-glycol based antifreeze which Is suitable for use In mixed-metal cooling systems, The quantity of antifreeze and levels of protection are
Indicated In
the Specifications. 24 8efore adding antifreeze, the cooling system should be completely drained, preferably flushed, and all hoses checked for condition and security. 25 After filling with antifreeze, a label should
be attached
to the expansion tank, stating the type and concentration of antifreeze used, and the date installed. Any subsequent lopping-up should be made with the same
type and
concentration of antifreeze. 26 Do not use engine antifreeze In the windscreen/tailgate washer system, as it will
cause damage to the vehicle paintwork. A screenwash additive should be added to the washer system in the quantities stated on the bottle.
34 Brake fluid renewal | I

A


Warning: Brake hydraulic fluid can harm your eyes and damage painted surfaces, so use extreme caution when handling and pouring H. Do not use fluid that has been standing open for some t/me, as it absorbs moisture from the air. excess moisture can cause a dangerous ioss of braking effectiveness. 1 The procedure is similar to that for the bleeding of the hydraulic system as described in Chapter 9, except that the brake fluid reservoir should be emptied by siphoning, using a clean poultry baster or similar before starting, and allowance should be made for the old fluid to be expelled when bleeding a section of the circuit. 2 Working as described In Chapter 9, open the first bleed screw in the sequence, and
pump the brake pedal gently until nearly all the old fluid has bsen emptied from the master cylinder reservoir.
Old hydraulic fluid Is Invariably much darker In colour than the new, making It easy to distinguish the two.
3 Top-up to the MAX level with new fluid, and continue pumping until onty the new fluid remans in the reservoir, and new fluid can be seen emerging from the bleed screw. Tighten the screw, and top the reservoir level up to the MAX level line. 4 Work through all the remaining bleed screws in the sequence until new fluid can be seen at all of them. Be careful to keep the master cylinder reservoir topped-up to above the MIN level et all times, or air may enter the system and greatly increase the length of the task. 5 When the operation Is complete, check that all bleed screws are securely tightened, and that their dust caps are refitted. Wash off all traces of spilt fluid, and recheck the master cylinder reservoir fluid level. 6 Check the operation of the brakes before taking the car on the road.
1A

2A«1
Chapter 2 Part A:
SOHC (8-valve) petrol
engine in-car repair procedures
Contents
Auxiliary drivebelts • removal and refitting See Chapter 1A Gamstaft cover - removal and refitting 6 Camshaft oil seal - renewal 7 Camshaft • removal and refitting See Chapter 20 Crankshaft oil seals - renewal 8 Cylinder compression test 3 Cylinder head - dismantling and overhaul See Chapter 20 Cylinder head - remove] and refitting 9 Engine mountings - Inspection and renewal 11 Engine oil and filter • renewal See Chapter 1A
Degrees of difficulty
Engine oil level check See Weekiy checks Flywheel/driveplate • removal, inspection and refitting 10 General Information 1 Location of TOC on No 1 cylinder 2 Oil pump and pick-up tube - removal, inspection and refitting 13 Sump • removal and refitting 12 Timing belt and covers • removal and refitting .. 4 Timing belt tensioner and sprockets - removal, inspection and refitting 5 Vafve clearance check and adjustment See Chapter 1A
Easy, suitable (or twics with little |g experience ^
Fairty easy, suitable jk for beginner with & some experience ^
Fatrty difficult, ^ suitable for competent ^ CKYmechanic ^
Difficult, suitable for ^ experienced DIY « mechanic ^
Veiy difficult, ^ aiitabte for expert DIY « or professional
Specifications
General Engine code:' 1108 cc engine (55 models): Up to May 1997 176.A6.000 May 1d97 onwards • . 176.B2.000 1242 cc engine (60 models): Up to May 1997 176.B1.000 May 1997 onward 176.B4.000 1242 cc engine (75 modete) 176.A8.000
•Note:
See Vehicle Identification for the location of code marking on the engine. 8cre: 11O0OC engine 70.0 mm 1242 cc engine 70.8 mm Stroke: 1108 cc engine 72.0 mm 1242 cc engine 78.86 mm Compression ratio: 1108 cc engine 9.6:1 1242 cc engine with single-point injection 9.6:1 1242 cc engine with multi-point injection 9.8:1 Rrlng order 1-3-4-2
No 1
cylinder location Timing belt end of engine
TnUng
belt tension See text
Lubrication system
Oil
pump type By-rotor driven from front of crankshaft Outer rotor-to-housing clearance 0.080to0.186mm
Axial
clearance 0.025 to 0.056 mm

2A*10 SOHC (8-valve) petrol engine in-car repair procedures
Torque wrench settings Nm
IM
ft Camshaft cover 8 6 Camshaft sprocket 70 52 Cylinder head; Stage 1 30 22 Stage 2 Angle-lighten a further 90° Siege 3 Angle-tighten a further 90B Crankshaft sprocket centre bott 100 74 Engine mounting bolt: M10X1.25 69 44 MB 25 18 Engine mounting nut (M10x 1.25) 60 44 Flywheet/driveplate 44 32 Sump 10 7 Timing belt tensJoner 28 21
1 General information
Using this Chapter Chapter 2 is divided Into four Parts: A. 8. C and D. Repair operations that can be carried out with the engine in the vehicle are described in Part A. SOHC (8-valve) petrol engines, Part B. DOHC (18-valve) petrol engines and Part C, diesel engines. Part 0 covers the removal of the engine/transmission as a unit, and describes the engine dismantling and overhaul procedures. In Parts A, 9 and C, the assumption Is made lhat the engine is Installed in the vehicle, with sll ancillaries connected. If the engine has been removed for overhaul, the preliminary dismantling Information which precedes each operation may be ignored.
Engine description Throughout this Chapter, engines are identified by their capacities. A listing of all engines covered, together with their code letters, is given in the Specifications. The engines covered In this Part of Chapter 2 are water-cooled, single overhead camshaft, in-line four-cylinder units, with cast Iron cylinder Mocks and aluminium-alloy cylinder heads. All are mounted transversely at the front ot the vehicle, with the transmission bolted to the left-hand side of the engine, The cylinder head carries the camshaft which is driven by a toothed timing belt and runs In three bearings. It also houses the inlet and exhaust valves, which are closed by single coil springs, and which run in guides pressed Into the cylinder head. The camshaft actuates the vatves directly via cam followers mounted in the cylinder head. Adjustment of the valve clearances is by means of shims located on top of the followers. The cylinder head contains Integral oitways which supply and lubricate the tappets. The crankshafl Is supported by five main bearings, and endftoat is controlled by a thrust bearing fitted to the upper section of the centre main bearing.
Engine coolant is circulated by 8 pump, driven by the timing belt. For details of the cooling system, refer to Chapter 3. Lubricant is circulated under pressure by a pump, driven from ihe front of the crankshaft. Oil Is drawn from the sump through a strainer, and then forced through an externally-mounted, replaceable screw-on filter. From there, It is distributed to the cylinder head, where It lubricates the camshaft journals and tappets, and also to the crankcase, where il lubricates the main bearings, connecting rod big and smell-ends, gudgeon pins and cylinder bores. On 1242 cc engines, oil jets are fitted lo the base of each cylinder bore -these spray oil onto the underside of the pistons, to Improve cooling.
Repair operations possible with the engine in the car The following work can be carried out with the engine in the car a) Compression pressure - testing b) Auxiliary drivebelt - removal and refitting (refer to Chapter 1A) c) Vatve clearances - checking and adjustment (refer to Chapter I A) d) Camshaft cover - removal and refitting e) Timing belt and covens - removal and refitting f) Timing belt tensioner and sprockets -removal and refitting g) Cylinder head - removal and refitting' h) Camshaft and cam followers • removal and refitting' t) Camshaft oil seal - renews/ j) Crankshaft oil seals - renewal k) Flywheel/dnvepfate • removal, inspection and refitting l) Engine mountings - inspection and renewal m)Sump - removal and refitting n) Oil pump and pick-up tube assembly
•
removai. inspection and refitting *Cylinder head dismantling procedures are detailed In Chapter SO, with details of camshaft and cam follower removal. Note: It is possible to remove the pistons and connecting rods (after removing the cylinder head and sump) without removing the engine. However, this is not recommended. Work of
this nature is more easily and thoroughly completed with the engine on the bench, as described In Chapter 2D.
2 Location of
TDC
on % No
1
cylinder
General Information 1 The camshaft Is driven by the crankshaft, by means of sprockets and a timing belt. Both sprockets rotate In phase with each other and this provides the correct valve timing as the engine rotates. When (he liming belt is removed during servioing or repair, it Is possible for the camshaft and crankshaft to rotate Independently of each other and the correct valve timing Is then lost. 2 The design of the engines covered In this Chapter are such lhat potentially damaging piston-to-valve contact may occur if the camshaft is rotated when any of the pistons are stationary at, or near, the top of their stroke. 3 For this reason it is important lhat Ihe correct phasing between the camshaft and crankshaft is preserved whilst the timing belt Is off the engine. This is achieved by setting the engine In a reference position (known as Top Dead Centre or TDC) before the timing belt Is removed and then preventing the camshaft and crankshaft from rotating until the belt is refitted. Similarly, if ths engine has been dismantled for overhaul, the engine can be set to TOC during reassembly to ensure that Ihe correct shaft phasing is restored. 4 TDC is the highest point In the cylinder that each piston reaches as the crankshaft turns. Each piston reaches TDC at Ihe end of the compression stroke and again at the end of the exhaust stroke. However, for the purpose of timing the ongine. TDC refers to the position of No 1 piston at the end of Its compression stroke. On ail engines In this manual, No 1 piston (and cylinder) Is at the timing belt end of the engine. 5 The camshaft sprocket Is equipped with a marking which, when aligned with a reference marking on the cylinder head, indicates that the camshaft is correctly positioned for cyl-inder No 1 al TDC on its compression stroke.

2A*10 SOHC (8-valve) petrol engine in-car repair procedures
2.11 Unscrewing the crankshaft pulley bolts
6 Itae crankshaft sprocket Is also equipped •nth a timing mark - when this is aligned with 3relarence marking on the oil pump cover.
Hie
engine is set with cylinders No 1 and 4 at
TDC.
Note that it is the camshaft positioning that determines whether a cylinder is on its comcression or exhaust stroke.

Location
of TDC on cylinder No 1 7 Remove the air cleaner and ducting as descnbed in Chapter 4A or 4B. Remove the
spark
plug from No 1 cylinder as described in Chapter 1A. 8 Firmly apply the handbrake, then |ack up
the
front of the car and support it securely on iiia stands (see Jacking end vehicle support). 9 Remove the auxiliary drivebelt(s) as described in Chapter 1A. 10 Unbolt and remove the timing belt cover. Mole the bolt located at the bottom of the
coven
this can be easily overlooked. 11 Undo the three bolts and remove the crankshaft pulley from the sprocket (see {lustration). 12 Turn Ihe engine in its normal direction of rotation (using a socket or spanner on Ihe crankshaft sprocket centre bolt) until pressure an be felt at No
1
cylinder spark plug hole.
1 flfliyflg^ Remove all four spark plugs; "••"•1 this will make the engine HlNTl easier to turn; refer to Chapter 1A for details.
13 Continue turning the engine until the crahaft sprocket TDC timing mark is aligned with the mark on the cylinder head and the crankshaft sprocket timing mark is aligned with the mark on the oil pump cover (see ilustrations). 14 The engine is now set at TDC for No 1 cylinder on compression.
3 Cylinder compression test t ^
1 When engine performance Is down, or if misfiring occurs which cannot be attributed to tne ignition or fuei systems, a compression isst can provide diagnostic clues as to the
2.13a Camshaft sprocket and cylinder head TDC timing marks (arrowed) aligned -shown with timing belt removed engine's condition. II the test is performed regularly, it can give warning of trouble any other symptoms become apparent. 2 The engine must be fully warmed-up to normal operating temperature, the battery must be fufly charged, and all the spark plugs must be removed (Chapter 1A). The aid of an assistant will also be required. 3 Disable the ignition system by dis-connecting the LT wiring plug to the ignition coils. 4 Fit a compression tester to the No 1 cyl-inder spark plug hole - the type of tester which screws into the plug thread is to be preferred, 5 Have the assistant hold the throttle wide open, and crank the engine on the starter motor; after one or two revolutions, the compression pressure should build up to a maximum figure, and then stabilise. Record the highest reading obtained. 6 Repeat the lest on the remaining cylinders, recording the pressure in each. 7 All cylinders should produce very similar pressures; any excessive difference indicates the existence of a fault. Note that the compression should build up quickly in a healthy engine; low compression on the first stroke, followed by gradually increasing pressure on successive strokes, indicates worn piston rings. A low compression reading on the first stroke, which does not build up during successive strokes, indicates leaking valves or a blown head gasket (a cracked head could also be the cause). 8 If the pressure in any cylinder is very low. carry out the following test to isolate the cause. Introduce a teaspoonful of clean oil into that cylinder through its spark plug hole and repeat the test. 9 If the addition of oil temporarily improves the compression pressure, this indicates that bore or piston wear Is responsible for the pressure loss. No improvement suggests that leaking or burnt valves, or a biown head gasket, may be to blame. 10 A low reading from two adjacent cylinders is almost certainly due to the head gasket having blown between them; the presence of coolant in the engine oil will confirm this. 11 If one cylinder is about 20 percent lower
2.13b Crankshaft sprocket and oil pump cover TDC timing marks (arrowed) aligned
than the others and Ihe engine has a slightly rough idle, a worn camshaft lobe could be the cause. 12 On completion of the test, refit the spark plugs and reconnect the ignition LT wiring plug.
4 Timing belt and covers -removal and refitting ^
Note: Fiat specify the use of a special timing belt fens/on measuring toot to correctly set tho timing belt tension. If access to this equipment cannot be obtained, an approximate setting can be achieved using the method described below. It the method described is used, the tension must be checked using the special tool at the earliest possible opportunity. Do not drive the vehicle over large distances, or use high engine speeds, until the belt tension is known fo be correct. Refer to a Fiat dealer foradvSce.
General information 1 The function of the timing belt is to drive Ihe camshaft and coolant pump. Should the belt slip or break In service, the valve timing will be disturbed and piston-to-valvo contact will occur, resulting in serious engine damage, 2 The timing belt should be renewed ai the specified intervals (see Chapter 1A), or earlier if it is contaminated with oil. or if it is at all noisy in operation (a scraping noise due to uneven wear). 3 If the timing belt is being removed, it Is a wise precaution to check the condition of the coolant pump at the same time (check for signs of coolant leakage). This may avoid the need to remove the timing belt again at a later stage, should the coolant pump fall.
Removal 4 Firmly apply the handbrake, then jack up the front of the car and support it securely on axle stands (see Jacking and vehicle support). Remove the right-hand front road wheel. 5 Remove the air cleaner and air ducting as described in Chapter 4A or 46. 6 Remove the auxiliary drivebelt(s) and the spark plugs as described in Chapter 1A.
2A