
2C*2 Diesel engine in-car repair procedures
1 General information
Using this Chapter Chapter 2 is divided Into four Parts; A. 8, C and 0. Repair operations that cart be carried out with the engine in the vehicle are described In Part A, SOHC (B-valve) petrol engines. Part B, DOHC (16-valve) petrol engines and Part C. diesel engines, Part D covers the removal of the engine/transmission as a unit, and describes the engine dismantling and overhaul procedures. In Parts A. 8 and C. the assumption Is made that the engine is installed in Ihe vehicle, with all anciliaries connected If the engine has been removed for overhaul, the preliminary dismantling information which precedes each operation may be ignored.
Engine description Both normally aspirated (non-turbo) and turbocharged diesel engines are fitted to the Punto range. The engines together with their codes are given in the Specifications at the start of lhis Chapter. The engines are water-cooled, single-overhead camshaft. In-line lour cylinder units with cast-iron cylinder blocks and aluminium-alloy cylinder heads. The engine is mounted transversely at the front of 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. It also houses the inlet and exhaust valves which are closed by single coll valve springs and run in valve guides pressed into the cylinder head. The valves are operated by cam followers fitted over each valve, and the clearances are adjusted by shims positioned between the followers and the camshaft lobes. The camshaft is supported by four bearings • the end bearings are machined in the cylinder head and the remaining bearings have caps bolted to the cylinder head. The cylinder head contains integral oiiways which supply and lubricate the camshaft and followers and it also Incorporates renewable swirl chambers. The crankshaft Is supported by five main bearings, and endfloat Is controlled by a thrust bearing fitted on the rear main bearing. All diesel engines are fitted with a brake servo vacuum pump dnven from the left-hBnd end of the camshaft. Engine coolant is circulated by a pump, driven by the auxiliary drivebeit. For details of the cooling system refer to Chapter 3. Lubricant is circulated under pressure by a pump, driven from the 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 il lubncates the camshaft journals and followers, and also to the crankcase, where it lubricates the main bearings, connecting rod big- and small-ends, gudgeon pins and cylinder bores. Oil jets are fitted to the base of each cylinder bore - these spray oil onto the underside of the pistons, lo Improve cooling. An oil cooler is also fitted to reduce the temp-erature of oil before it re-enters the engine.
Repair operations possible with the engine in the car The following work can be carried out with the engine in the can a) Compression pressure - testing b) Auxiliary drivebeit - removal and refitting (refer to Chapter rej c) Valve clearances • checking and adjustment (refer to Chapter 1B) d) Camshaft cover - removal and refitting e) Tim/ng belt and covers • removal and refitting 0 Timing belt tensioner and sprockets -removal and refitting g) Cylinder head - removal and refitting' h) Camshaft and cam followers - removal end refitting' I) Camshaft oil seal - renewal j) Crankshaft oil seals - renewal k) Flywheel • removal, inspection and refitting I) Engine mountings - inspection and renewal m)Sump • removal and refitting n) Oil pump and pick-up tube assembly -removal, inspection and refitting 'Cylinder head dismantling procedures are detalfed In Chapter 2D, with details of camshaft and cam follower removal. Note: It ts possible to remove the pistons and connecting rods (after removing the cylinder nead 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 tho bench as described in Chapter 2D.
2 Location of
TDC
on ^ No
1
cylinder ||
General information 1 The camshaft and fuel Injection pump are driven by the crankshaft, by means of sprockets and a timing belt. All three sprockets rotate in phase with each other and this provides the correct valve and injection pump timing as the engine rotates. When the timing bell is removed during servicing or repair, it is possible for the camshaft, injection pump and crankshaft to rotate independently of each other and the correct timing Is then lost.
2 It
Location of TDC on cylinder No
1
6 Remove the air inlet ducting as described ft Chapter 4C, Section 2. 7 Remove the heater glow plugs with reference to Chapter 5C. Due to the high compression ratio of diesel engines this Is necessary to allow the engine to be turned by hand. 8 Unscrew the mounting bolts and move the coolant expansion tank to one side for access to the timing covers. Release the hose from the clips on Ihe camshaft cover. 9 Release the toggle clips and remove the upper timing cover (see illustration),
2.9 Removing the upper timing cover

4A*2 Fuel system - single-point petrol Injection models
2.4a Disconnect the large breather hose... ziecessary when handling it cannot be mrstressed. Note that residual pressure
wttf
remain in the tuei lines long after the wh/cte was last used, When disconnecting any fuel line, first depressurise the fuel
system
(see Section 8).
2 Air cleaner and intet system • removal and refitting
1
Accelerator cable -removal, refitting and adjustment l
Removal 1 Remove the air cleaner element as described in Chapter 1A. 2 Disconnect the outer section from the hot
air
tube and the inlet air duct and remove it
from
the engine compartment. 3II necessary remove the inlet air duct. 4 Disconnect Ihe large and small breather
roses
from the inner section of the air cleaner, tftsn unscrew the retaining nuts and lift the section from the throttle body (see lustrations).
5
Recover the sealing ring. Check the ring for condition and renew it if necessary.
6
Wipe clean the inner surfaces of both the merand outer sections of the air cleaner. Refitting 7 Refitting Is a reversal ol removal but renew
tie
element
H
necessary.
3 Inlet air temperature regulator -removal and refitting
Removal t
The
thermostatically-controlled cold air flap cpener is located in the air cleaner outer ttsrig section. To check the unit, disconnect
ire air
inlet duct with the engine cold and use imrrorto check that the flap Is positioned to aJmit only hot air from the shroud on the utaust manifold. Next, warm up the engine
and
check that the flap moves to admit only sett air from the inlet duct. If the unit is faulty fl must be renewed.
2
Remove the air cleaner element as •senbod in Chapter
1
A.
kickdown cable adjustment as described in Chapter 7B before adjusting the accelerator cable • in its rest position the accelerator pedal should have approximately 8.0 mm free travel.
5 Engine management system components -removal and refitting I
2.4b ... and the small breather hose ...
3 Unscrew the retaining screw and remove the regulator from the air cleaner outer section.
Refitting 4 Refitting is a reversal of removal.
Removal 1 Remove the air cleaner and air inlet ducting as desenbed in Section 2. 2 To release the cable from the throttle body, unscrew the outer cable locknuts, then disengage the inner cable from the throttle cam, and release the outer cable from its mounting bracket. 3 Working under the instrument panel inside the vehicle, unhook the cable from the fork at the top of the pedal arm. 4 Release the bulkhead grommet and withdraw the accelerator cable from Inside the engine compartment.
Refitting and adjustment 5 Refitting is a reverse of the removal process, but adjust the cable (by means of the outer cable locknuts) so that there is only a very small amount of free play present at the throttle body end of the inner cable. Have an assistant depress the accelerator pedal, and check that the throttle cam opens fully and returns to the at-rest position, then secureJy tighten the cable locknuts. On Selecta models, check the
Note: Refer to the warning given in Section 1 before proceeding. Throttle body assembly
Removal 1 Remove the air cleaner and air duct as desenbed in Section 2. 2 Disconnect the wiring connectors from the throttle potentiometer, idle control stepper motor, inlet air temperature sensor and the injector wiring loom connector situated on the front of the throttle body. 3 Depressurise the fuel system with reference to Section 8, then release the retaining clips and disconnect the fuel feed and return hoses from the throttle body assembly, if the original Fiat retaining clips are still fitted, cut the clips and discard them; replace them with standard luel hose clips on refitting. 4 Slacken the accelerator cable locknuts, then disengage the inner cable from the throttle cam and froe tho outer cable from its retaining bracket. Position the cable clear of the throttle body. 5 Disconnect the EVAP purge valve hose, and the MAP sensor hose from the rear of the throttle body. 6 Slacken and remove the four bolts securing the throttle body assembly to tho Inlet manifold, then remove the assembly along with its insulating spacer. Refitting 7 Refitting is a reversal of the removal pro-cedure, bearing in mind the following points: a) Examine the insulating spacer for signs of damage, and renew //necessary, b) Ensure that the throttle body, inlet manifold and insulating spacer ma ting surfaces are clean and dry, then fit the throttle body and spacer, and securely tighten the retaining bolts.
2.4c ... then remove the retaining nuts. 2.4d ... and remove the air cleaner inner section

4A*2 Fuel system - single-point petrol Injection models
1 The luel system referred to In this Section is defined as the tank-mounted fuel pump, the fuel litter, the throttle body and pressure regulator components, and the metal pipes and flexible hoses of the fuel lines between these components. All ihese contain fuel which will be under pressure while the engine Is running and/or while tha Ignition is switched on. The pressure will remain for some time after tho ignition has been switched off, and must be relieved before any of these components are disturbed (or servicing work. 2 Disconnect the battery negative terminal (refer to D/sconnecf/ngr the battery in the Reference Section of this manual), 3 Place a container beneath the relevant connection/union to be disconnected, and have a large rag ready to soak up any escaping fuel not being caught by the container. 4 Slowly loosen the connection or union nut (as applicable) to avoid a sudden release of pressure, and wrap tho rag around the connection to catch any fuel spray which may be expelled. Once the pressure is released, disconnect the fuel line, and Insert plugs to minimise fuel loss and prevent the entry of dirt Into the fuel system.
9 Inlet manifold -removal and refitting ^
Note: Refer to the warning given In Section 1 before proceeding.
Removal 1 Remove the throttle body assembly as described in Section 5. 2 Drain the cooling system as described in Chapter 1A. 3 Disconnect the winng connector from the coolanl temperature sensor (situated on the left-hand sidB of the manifold). 4 Undo the bolt securing the accelerator cable mounting bracket to the manifold, and position it clear of the manifold. 5 Slacken the retaining clip and disconnect tha coolant hose from the rear of the manifold. 6 Disconnect the brake vacuum hose. 7 Undo the seven manifold retaining nuts and
10.2 The diagnostic connector la located behind the ECU bolts, and remove (he manifold from the engine. Remove the gasket and discard It; a new one should be used on refitting.
Refitting 8 Refitting is a reverse of the removal procedure, noting the following points: a) Ensure that the manifold and cylinder head mating surfaces are clean and dry, and fit a nev/ manifold gasket. Refit the manifold and securely tighten Its retaining nuts. b) Ensure that all relevant hoses are reconnected fo their original positions and are securely held (where necessary) by the retaining clips. c) Refit the throttle body assembly with reference to Section S. d) On completion, refill the cooling system as described In Chapter 1A.
correctly adjusted, and that the engine breather hoses are clear and undamaged. 2 If these checks fall to reveal the cause of the problem, the vehicle should be taken to a suitably-equipped Fiat dealer for testing. A wiring block connector Is Incorporated In the engine management circuit, into which a special electronic diagnostic tester can be plugged; the connector is situated behind the ECU (see Illustration). The tester will locate the fault quickly and simply, alleviating the need to test all the system components Individually, which is a time-consuming operation that carries a high risk of damaging the ECU.
Adjustments 3 As mentioned above, the idle speed and mixture adjustment are all monitored and controlled by the ECU, and are not adjustable Experienced home mechanics with a considerable amount of skill and equipment (including a good-quality tachometer and a good-quality, carefully calibrated exhaust gas analyser) may be able to check the exhaust CO level and ihe idle speed. However, If thes* are found lo be in need of adjustment, the car must be taken to a suitably-equipped Flat dealer for testing using the special test equipment which is plugged into the diagnostic connector.
11 Unleaded petrol -general Information and usage
10 Fuel injection system - & testing and adjustment S
Testing 1 If a fault appears in the fuel injection system, first ensure that all the system winng connectors are securely connected and free of corrosion. Then ensure that the fault Is not due to poor maintenance; ie, check that the air cleanor fitter element is clean, the spark plugs are In good condition and correctly gapped, that tho valve clearances are
Note: The information given in this Chapter
is
correct at the time of writing. If updated Information is thought to be required, check with a Fiat dealer. If travelling abroad, consult one of the motonng organisations (or a similar authority) for advice on the fuel available. 1 All petrol models are fitted with a catalytic converter and must be run on unleaded fuel only - the fuel recommended by Flat is given In the Specifications of this Chapter. Under no circumstances should leaded fuei (UK 4-slar) be used, as this may damage the converter. 2 Super unleaded petrol (98 octane) can also be used in all models if wished, though there is no advantage in doing so.

4B*1
Chapter 4 Part B:
Fuel system - multi-point petrol injection models
Contents
Accelerator cable - removal, refitting and adjustment 4 Air cleaner and Inlet system • removal and refitting 2 Air cleaner filter element renewal See Chapter 1A Engine management system components (1242 cc, 8-valve engines) -removal and refitting 5 Engine management system components (1242 cc, 16-valve engines) - removal and refitting 6 Fuel filter renewal See Chapter 1A Fuel Injection system - depressurisation 9
Degrees of difficulty
Fuel injection system - testing and adjustment 11 Fuel pump and fuel gauge sender unit - removal and refitting 7 Fuel tank - removal and refitting 8 General Information and precautions 1 Idle speed and mixture adjustment See Chapter 1A Inlet air temperature regulator - removal and refitting 3 Inlet manifold - removal and refitting 10 Unleaded petrol • general Information and usage 12
Easy, suitable
for ^
novice with
Ittie experience ^
Fairly
easy,
suitable Jk for beginner
with
® someexperiencs ^
FaMycSffiait, J^ suitable
for
competent ^
DIY mechanic
^
Difficult
suitable
for experienced BY SJ mechanic ^
Very difficult,
^
suitable
for expert
DIY
jR or professional ^
Specifications
System type
Fuel system data Fuel pump type Fuel pump delivery rate: 1242 cc (8-vatve) engine 1242 cc (16-valve) engine Regulated fuel pressure: 1242 cc (8-vaive) engine: Pre-1998 models 1998 models onward 1242 cc (16*valve) engine Crankshaft TDC sensor resistance al 20°C Injector electrical resistance: Pre-1998 models 1998 models onward Injector duration (at Idle)
Recommended fuel Minimum octane rating
Torque wrench settings Coolant temperature sensor
Idle
control stepper motor Inlet manifold brake servo union Inlet manifold upper section-to-lower section (16-valve engines) Inlet manifold-to-cylinder head (16-valve engines) Inlet manlfold-to-cylinder head (8-valve engines) Throttle body to manifold Throttle potentiometer
Weber-Marelli integrated multi-point fuel injection/ignition system
Electric, immersed In fuel tank
120 Hires/hour minimum 110 litres/hour minimum
2.5 bars 3.5 bars 3.0 bars 650 to 720 ohms
16.2 ohms 13.8 to 15.2 ohms 2.0 ms
95 RON unleaded
Nm Ibfft a 2 4 3 35 26 9 7 15 11 27 20 7 5 3 2

4A*2 Fuel system -
single-point
petrol Injection models
2.8 Undo tho two bolts securing the resonator to the camshaft cover
8 Undo the two bolts securing the resonator to the camshaft cover (see illustration) 9 Release ihe wiring loom support clip from the slot on the side of the resonator lower extension, then lift the resonator off the camshaft cover (see illustrations). Disconnect Ihe crankcase breather hose from the underside of tho resonator and remove the resonator from the engine. 10 Undo the nuts secunng the sides of the air cleaner to the mounting brackets at the front of the engino. 11 Release the hose clip and disconnect the inlet air duct from the throttle body. 12 Release the crankcase ventifation hose from the pipe stub on the camshaft cover then remove the air cleaner and inlet air duct assembly from the engine (see illustration).
Refitting 13 Refitting is a reversal of removal but renew the air cleaner element as described In Chapter
1 A,
if necessary.
Inlet air temperature regulator -liWfii' I
2.9o Release the wiring support clip (arrowed) from the slot on the resonator lower extension ...
the shroud on the exhaust manifold. Next, warm up tho engine and check that the flap moves to admit only cold air from the Inlet duct. If the unit is faulty it must be renewed. 2 Remove the air cleaner element as described in Chapter
1
A. 3 Unscrew tha retaining screw and remove tho regulator from the air cleaner outer section.
Refitting 4 Rofitting is a reversal of removal.
I
Removal 1 The thermostatically-controlled cold air flop opener, fitted to 8-valve engines, is located in the air cleaner outer cos>ng section. To check lha unit, disconnect the atr inlet duct with the engine cold and use a mirror to check that the flap Is positioned to admit only not air from
2.12 Removing the air cleaner and Inlet air duct assembly
4 Accelerator cable -removal, refitting and adjustment
1242 cc (8-valve) engines
Removal 1 Remove Ihe air cleaner as described In Section 2. 2 To release the cable from the throttle body, unscrew the outer cable locknuls, then disengage the inner cable from the throttle cam, and release the outer cable from its mounting bracket, 3 Wording under the instrument panel inside the vehicle, unhook the cable from tho fork at the top of the pedal arm. 4 Release the bulkhead grommel and withdraw tho accelerator cable from inside Ihe engine compartment. Refitting and adjustment 5 Refitting is a reverse of the removal process, but ad|ust the cable (by means of the outer cable locknuts} so that there Is only a very small amount of free play present at the throttle body end of the inner cablo. Have an assistant depress the accelerator pedal and check that the throttlo cam opens fully and returns to the at-rest position, then securely tighten the cable locknuts.
1242 cc (16-valve) engines
Removal 6 Dlsconnoel the battery negative terminal (refer to Disconnecting the battery in the Reference Section of this manual), 7 Remove the resonator, air cleaner and Inlet air duct as described in Section 2.
camshaft cover
8 Undo the engine management ECU mounting bracket bolts, release the ECU wiring loom from Ihe support clips and move tho ECU and wiring loom to one side for access to the accelerator cable. 9 Free the accelerator inner cable from the throttle cam, remove the outer cable spring clip, then pull the outer cable out from its mounting bracket rubber grommet (see illustration). 10 Trace the cable back to its entry point in the engine compartment bulkhead and undo the bulkhead support bracket mounting bolt. 11 Working back along the length of the cable, free It from any retaining clips or ties, noting its correct routing. 12 Working under the instrument panel Inside the vehicle, unhook the cable from the fork at the top of the pedal arm. 13 Release the bulkhead support bracket and withdraw the accelerator cable from inside the engino compartment. Refitting end adjustment
14 Refitting is a reverse of the removal process, but adjust the cable as follows before refitting the outer cable spring clip. 16 Ensuring that the throttle cam is fully against its stop, gently pull the cable out of its grommet until all free play Is removed from the inner cable. 16 With the cable held in this position, lit the spring clip to tho first outer cable groove visible in front of the mounting brackot rubber grommet. This should leave a small amount of freeplay in tho inner cable which is necessary to ensure correct throttle operation.
4.9 Accelerator outer cable spring clip (arrowed)

4A*2 Fuel system -
single-point
petrol Injection models
17 Have an assistant depress the accelerator pedal and check that the throttle cam opens luily and returns smoothly to its stop. If necessary, reposition the spring clip In the next outer cable groove and recheck the throttle operation. 18 Refit the remainder of the disturbed components.
5 Engine management
system
^ components
(1242
cc, 8-vatve § engines) -
removal and refitting
^
Note: Refer to the warning given In Section T
before
proceeding.
Throttle body assembly
Removal 1 Remove the air cleaner and inlet air duct as described in Section 2. 2 Disconnect the wiring connectors from the throttle potentiometer, the idle control stepper motor and the inlet air temperature sensor. 3 Slacken the accelerator cable locknuts, then disengage the inner cable from the throttle cam and free the outer cable from its retaining bracket. Position the cable clear of the throttle body. 4 Unclip and disconnect the EVAP purge valve hose, and Ihe MAP sensor hose from the rear of the throttle body then, where applicable, disconnect the fuel pressure regulator vacuum hose from the front of the throttle body. 5 Slacken and remove the four bolts securing the throttle body assembly to the inlet manifold, then remove the assembly along with its insulating spacer. Refitting 6 Refitting is a reversal of the removal pro-cedure. bearing in mind the following points: 4! Examine the Insulating spacer for signs of damage, and renew If necessary. b) Ensure the throttle body, inlet manifold and insulating spacer mating surfaces are clean and dry, then fit the throttle body and spacer, and securely tighten the retaining bolts. c) Ensure ail hoses are correctly reconnected and, where necessary, /her their retaining clips are securely tightened. d) Adjust the accelerator cable as described in Section 4.
Fuel
rail and injectors
Removal 7 Disconnect the battery negative terminal (refer to Disconnecting tho battery in the Reference Section of this manual). 6 Remove the throttle body assembly as described earlier in this Section, however it is only necessary to move the unit to one side for access to the fuel rail and therefore it Is unnecessary to disconnect the accelerator caWe and hoses etc.
9 Depressurise Ihe fuel system as described in Section 9. 10 Loosen the clips or release the quick-release couplings and disconnect the fuel inlet and, on pre-1998 models, outlet hoses from the fuel rail. Note the fitted positions of the hoses to aid refitting later. 11 Unplug the ln}ector wiring harness connectors, labelling them to aid correct refitting later. 12 Unscrew the bolts securing the fuel rail assembly to the Inlet manifold, then carefully pull the Injectors from the Inlet manifold. Remove the assembly from the engine and remove the injector lower O-ring seals. 13 The injectors can be removed Individually from the fuel rail by extracting the relevant metal clip and easing Ihe injector out of the rail. Remove the injector upper O-ring seals (see illustration).
14 On pre-1998 models, if necessary remove the retaining clip and remove the fuel pressure regulator from the fuel rail. 15 Check the electrical resistance of the injector using a multimeter and compare It with the Specifications. Note: If a faulty Injector is suspected, before condemning the injector, It is worth trying the effect of one of the proprietary injector-cleaning treatments. Refitting 16 Refit the injectors and fuel rail by following the removal procedure, in reverse, noting the following points: a) Renew the injector O-rlng seals, and smear them with a little Vaseline before assembling. Take care when fitting the injectors to the fuel rail and do not press them in further than required to fit the retaining clip otherwise the O-ring seal may be damaged.
1 Fuel rail 2 Fuel pressure regulator 3 Injectors
5.13 Fuel rail and Injector removal 4 Vacuum stub connect/on 5 Fuel inlet hose 6 Fuel return hose
7 Mounting bolts 8 Injector mounting dip 9 Injector mounting dip

4A*2 Fuel system -
single-point
petrol Injection models
17 Unscrew the two bolts securing the fuel fell assembly to the Inlet manifold lower section, then carefully pull the injectors from Ihe manifold. Lift the fuel rail and injector assembly, with fuel hoses still connected, and position it to one side (see Illustration). 18 Disconnect the heater hose from the manifold stub. 19 Undo the engine oil dipstick tube bracket retaining bolt and the two bolts securing the *
one should be used on refitting. Refitting
21 Refitting is a reverse of the removal
procedure, noting the following points: a) Ensure that tha manifold and cylinder head mating surfaces are clean and dry. and fit
a
new manifold
gasf
f) On completion, refill the cooling system as described in Chapter 1A.
11 Fuel injection system testing and adjustment
Refer to Chapter 4A.
12 Unleaded petrol -general information and usage
Refer to Chapter 4A.
10.16 Disconnect the wiring connectors and hoses from the fuel rail and manifold 1 Fuel injector harness wiring connector 2 Intake air temperature/pressure sensor wiring connector 3 Fuel pressure regulator vacuum hose 4
EVAP
purge valve hose
10.17 Lift off the fuel rail and injector assembly, with fuel hoses still connected, and position it to one side

Fuel system - diesel models 4C*3
Torque wrench settings Nm Ibfft Fuel injection pump roar bracket .. . 29 21 Fuel Injection pump .... 25 18 Fuel Injectors 41 Fuel pipe union nuts .... 30 22 Inlet manifold .... 24 18 Lower oil tiller mounting and injection pump mounting nut ..... .... 71 S2 Turbocnarger to exhaust manifold .... <10 30 Upper Dtl filter mounting end injection pump mounting nut 98 72
1 General information and precautions
General information The fuel system consists of a rear-mounted fust tank, a fuel filter with integral water separator, a fuel injection pump, in|eciors and associated components. A turbocharger is fitted to TDS, TD and TDSX models. Fuel Is drawn from the fuel tank to the fuel Injection pump by a vane-type transfer pump Incorporated in the fuel injection pump. Before reaching tho pump, the fuel passes through a fuel filter, where foreign matter and water aro removed. Excess fuel lubricates the moving components of the pump, and Is then returned to the tank. On turbo models with the Bosch fuel Injection systom, an eiectncally operated heater is incorporated In the fuel filter housing. The fuel injection pump is driven at half-crankshaft speed by the timing belt. The nigh pressure required to inject tho fuel into the compressed air in the swirl chambers Is achlovod by a cam plate acting on a single piston on the Bosch pumo, or by two opposed pistons forced together by rollers running in a cam ring on the Lucas (CAV) pump. Tlie fuel passes through acentral rotor with a single outlet drilling which aligns With ports leading to the Injector pipes. Fuel metering is controlled by a centrifugal governor, which reacts to accelerator pedal
position end engine speed. The governor is linked lo a metering valve, which increases or decreases the amount of fuel delivered at each pumping stroke. On turbocharged models, a separate device also Increases luel delivery with increasing boost pressure. Basic injection timing is determined when the pump is fitted. When the engine is running, it Is varied automatically to suit the prevailing engine speed by a mechanism which turns the cam plate or ring, Tho four fuel injectors proouco a homogeneous spray of fuel Into the swirl chambers located In the cylinder head. The Injectors are calibrated to open end close at critical pressures lo provide efficient and even combustion. Each injector needle is lubricated by fuel, which accumulates In the spring chamber and is channelled to the injection pump return hose by loak-off pipes Bosch or Lucas fuel system components mBy be fitted, depending on the model. Components from the latter manufacturer are marked either CAV. Roto-dlesel or Con-diesel. depending on their date and place of manufacture. With the exception of the fuel filter assembly, replacement components must be of tho same make as those originally fitted. Cold starting is assisted by preheater or glow plugs fitted to each swirl chamber. On the Bosch injection pump, an automatic cold Injection advance device operated through a thermal switch, advances the injection timing by Increasing the fuel pressure. The device operates at coolant temperatures below 55° C,
A stop solenoid cuts the fuel supply to V* Injection pump rotor when the ignition i switched off (see illustration) Provided that the specified maintenance* earned out. the fuel injection equipment #» give long and trouble-free service, ft* j injection pump itself may well outlast tlx ' engine, The main potential cause of damage j to the injection pump and injectors is dirt e water in the fuel. 1 Servicing of the injection pump and injectwi: j, is very limited for tho home mechanic, antf dismantling or adjustment other than thtf described In this Chapter must be entrusted to ' a Rat dealer or fuel Injection specialist.
Precautions
A
Warning: It Is necessary to takt I certain precautions when woriong , on the fuel system component^ particularly the fuel Injectors. Befon carrying out any operations on tho fuel system, refer to the precautions given* Safety first! at the beginning of Mis manual, and to any additional wamlrq notes at the start of the relevant
Sections.
2 Air cleaner and inlet system ^ • removal and refitting S
Removal 1 Remove the air cleaner element u described In Chapter 1B (see illustration).
1.9 Stop solenoid on the injection pump 2.1 Releasing the air cleaner cover clips