FORD SIERRA 1993 2.G Fuel And Exhaust Systems Carburettor User Guide

Fuel and exhaust systems - carburettor 4A•11
4A
13.4d Exploded view of Weber 2V carburettor - 2.0 litre models from 1985
A Top cover assembly
B Automatic choke assembly
C Automatic choke bi-metal housing
D Secondary idle jet
E Secondary throttle valve vacuum unit
F Stepper motorG Idle mixture screw
H Accelerator pump assembly
J Power valve diaphragm
K Low vacuum enrichment diaphragm
L FloatM Primary emulsion tube
N Primary idle jet
P Needle valve
Q Fuel filter
R Secondary emulsion tube

4A•12Fuel and exhaust systems - carburettor
13.4e Exploded view of Pierburg 2V carburettor
A Automatic choke bi-metal housing
B O-ring
C Automatic choke coolant housing
D Automatic choke vacuum pull-down
unitE Secondary throttle valve vacuum unit
F Idle speed screw
G Accelerator pump diaphragm
H Power valve assembly
K Carburettor bodyL Fuel inlet pipe and filter
M Primary main jet
N Secondary main jet
O Top cover assembly
P Idle jet

Fuel and exhaust systems - carburettor 4A•13
4A
13.4f Exploded view of Weber 2V TLD carburettor
A Anti-dieselling valve
B Emulsion tubes
C Air correction jets
D Choke pull-down diaphragm assembly
E Choke linkage
F Needle valve
G Float
H Fast idle adjustment screw
J Idle speed adjustment screw
K Idle mixture adjustment screw
L Throttle valves
M Power valve assembly
N Accelerator pump assembly
P Low vacuum enrichment device
Q Throttle kicker
R Gasket
S Main jets
Note: A new gasket must be used when
refitting the carburettor. A tachometer and an
exhaust gas analyser will be required to check
the idle speed and mixture on completion.
Removal
1Disconnect the battery negative lead.
2Remove the air cleaner.
3Relieve the pressure in the cooling system
by unscrewing the expansion tank cap. If the
engine is warm, place a thick rag over the cap
and unscrew the cap slowly as a precaution
against scalding. Refit the cap after relieving
the pressure.4Identify the automatic choke coolant hose
locations, as an aid to refitting, then
disconnect the hoses (being prepared for
coolant spillage.) Either plug the hoses or
secure them with their ends facing upwards to
prevent loss of coolant.
5Disconnect the wiring from the anti-dieselling (anti-run-on) valve.
6Disconnect the fuel hose and vacuum pipe
(see illustration). Plug the end of the fuel
hose to minimise petrol spillage.
7Disconnect the throttle cable from the
carburettor throttle lever (see illustration).
8Remove the two securing nuts and
14Carburettor (Ford VV type) -
removal and refitting
14.7 Disconnecting the throttle cable from
the throttle lever - Ford VV carburettor14.6 Disconnecting the fuel hose - Ford VV
carburettor
Caution: Refer to the
precautions in Section 1 before
proceeding.

washers, and lift the carburettor from the inlet
manifold studs (see illustrations). Recover
the gasket.
Refitting
9Refitting is a reversal of removal, bearing in
mind the following points.
10Ensure that the mating faces of the inlet
manifold and carburettor are clean, and use a
new gasket.
11Ensure that the coolant hoses, fuel hose,
and vacuum pipe are correctly routed and free
from restrictions. If any of the hoses were
originally secured with crimped type clips,
discard these and use new worm drive clips
on refitting.
12On completion, check and if necessary
top-up the coolant level. Check and if
necessary adjust the idle speed and mixture.
Refer to Chapter 1, Sections 15 and 16.
1Proceed as described for the Ford VV
carburettor but note the following.
2On models with an electrically-heated
automatic choke, ignore all references to the
cooling system and coolant hoses.3Not all Weber carburettors are fitted with an
anti-dieselling valve.
4Disconnect all relevant wiring plugs and
vacuum pipes, if necessary noting their
locations for use when refitting.
5Disconnect the link arm from the throttle
linkage instead of disconnecting the throttle
cable.
6The carburettor is secured to the inlet
manifold by four nuts and washers.
Refer to Chapter 1, Sections 15 and 16.
1This procedure does not apply to models
fitted with a carburettor stepper motor, for
which no adjustment is possible.
2Check the idle speed and mixture. The idle
speed must be correct before attempting to
check or adjust the fast idle speed.
3With the engine at normal operating
temperature, and a tachometer connected in
accordance with the manufacturer’s
instructions, proceed as follows.
4Remove the air cleaner.
5Partially open the throttle, hold the choke
plate(s) fully closed, then release the throttle
so that on 1.6 litre models the fast idle
adjustment screw rests on the third (middle)
step of the fast idle cam (see illustration)and
on 2.0 litre models the fast idle adjustment
screw rests on the highest step of the fast idle
cam (see illustration).
6Release the choke plate(s), checking that
it/they remain(s) fully open; if not, the
automatic choke mechanism is faulty, or the
engine is not at normal operating temperature.
7Without touching the throttle pedal, start
the engine and check that the fast idle speed
is as specified. If adjustment is necessary,
turn the fast idle adjustment screw until the
correct speed is obtained.
8On completion of adjustment, stop the
engine and disconnect the tachometer, then
refit the air cleaner.1Proceed as described for the Ford VV
carburettor but note the following.
2The Pierburg carburettor is not fitted with
an anti-dieselling valve.
3Disconnect all relevant wiring plugs and
vacuum pipes, if necessary noting their
locations as an aid to refitting.
4Disconnect the throttle arm from the throttle
lever by removing the retaining clip instead of
disconnecting the cable (see illustration).
5The carburettor is secured to the inlet
manifold by three Torx type screws (see
illustration).
6On CVH models an insulator block is fitted
between the carburettor and the inlet manifold
in place of a gasket. There is no need to
renew the insulator block on refitting.
19Carburettor (Pierburg 2V
type) - removal and refitting
18Carburettor (Weber 2V type) -
fast idle speed adjustment
17Carburettor (Weber 2V type) -
idle speed and mixture adjustment16Carburettor (Weber 2V type) -
removal and refitting
15Carburettor (Ford VV type) - idle
speed and mixture adjustment
4A•14Fuel and exhaust systems - carburettor
14.8a Remove the securing nuts and
washers . . .
19.4 Throttle arm retaining clip (arrowed) -
Pierburg 2V carburettor
19.5 Removing the carburettor securing
screws (arrowed) - Pierburg 2V carburettor18.5b Fast idle speed adjustment - Weber
2V carburettor (2.0 litre models)
18.5a Fast idle speed adjustment - Weber
2V carburettor (1.6 litre models)
A Screw on third (middle) step of cam
B Fast idle screw
14.8b . . . and lift the carburettor from the
inlet manifold - Ford VV carburettor

Refer to Chapter 1, Sections 15 and 16.
1Check the idle speed and mixture
adjustment. The idle speed must be correct
before attempting to check or adjust the fast
idle speed.
2With the engine at normal operating
temperature, and a tachometer connected in
accordance with the manufacturer’s
instructions proceed as follows.
3Remove the air cleaner.
4Position the fast idle speed adjustment
screw on the lowest (6th) step of the fast idle
cam (see illustration).
5Check that the fast idle speed is as
specified. If adjustment is required, stop the
engine and proceed as follows.
6Remove the tamperproof cap from the fast
idle speed adjustment screw.
7Ensure that the adjustment screw is still
resting on the lowest step of the fast idle cam,
then open the throttle so that a small
screwdriver can be used to adjust the screw
from below the carburettor.
8Start the engine and recheck the fast idle
speed.
9If necessary, repeat the procedure given in
paragraphs 7 and 8 until the correct fast idle
speed is obtained.
10On completion of adjustment, stop the
engine and disconnect the tachometer, then
refit the tamperproof cap to the adjustment
screw, and refit the air cleaner.Note: A new gasket must be used when
refitting the carburettor. A tachometer and an
exhaust gas analyser will be required to check
the idle speed and mixture on completion.Removal
1Disconnect the battery negative lead.
2Remove the air cleaner.
3Disconnect the wiring from the anti-
dieselling (anti-run-on) valve.
4Disconnect the wiring from the automatic
choke heater.
5Disconnect the fuel supply and return
hoses, noting their locations to aid refitting.
Plug the ends of the hoses to minimise petrol
spillage.
6Disconnect the link arm from the throttle
linkage.
7Disconnect the vacuum pipe.
8Release the coolant hose from the bracket
under the automatic choke housing.
9Unscrew the four Torx screws, and lift the
carburettor from the inlet manifold. Recover
the gasket.
Refitting
11Refitting is a reversal of removal, bearing
in mind the following points.
12Ensure that the mating faces of the inlet
manifold and the carburettor are clean, and
use a new gasket.
13Ensure that all hoses, pipes and wiring are
correctly routed, and free from restrictions. If
any of the hoses were originally secured with
crimped-type clips, discard these, and use
new worm-drive clips on refitting.
14Make sure that the coolant hose is
correctly positioned in the bracket under the
automatic choke housing.
15On completion, check and if necessary
adjust the idle speed and mixture.
Refer to Chapter 1, Sections 15 and 16.1Proceed as described for the Weber 2V
carburettor, noting the following.
2The fast idle adjustment screw should be
positioned on the third (middle) step of the
fast idle cam (see illustration).
3Refer to the Specifications at the beginning
of this Chapter for the correct fast idle speed.
SOHC models
Removal
1Disconnect the battery negative lead.
2Partially drain the cooling system.
3Remove the air cleaner.
4Disconnect the coolant hoses from the
automatic choke (where applicable), and the
inlet manifold. Identify the hose locations for
use when refitting.
5Disconnect the fuel supply hose at the
carburettor and plug the end to minimise
petrol spillage.
6Disconnect all relevant wiring and vacuum
pipes from the carburettor, if necessary noting
the locations for use when refitting.
7Disconnect the throttle cable from the
throttle linkage.
8Disconnect the crankcase ventilation and
brake servo vacuum hoses from the inlet
manifold. The brake servo vacuum hose is
secured with a union nut (see illustrations).
9Disconnect any remaining wiring and
vacuum pipes from the inlet manifold, if
necessary noting the locations as an aid to
refitting.
10Where necessary, unbolt the throttle cable
bracket from the top of the inlet manifold for
improved access, and unbolt the dipstick tube
bracket.
11Unscrew the two nuts and four bolts
securing the manifold to the cylinder head,
noting the location of the rear engine lifting
25Inlet manifold - removal and
refitting
24Carburettor (Weber 2V TLD) -
fast idle speed adjustment
23Carburettor (Weber 2V TLD) -
idle speed and mixture adjustment
22Carburettor (Weber 2V TLD) -
removal and refitting
21Carburettor (Pierburg 2V type)
- fast idle speed adjustment
20Carburettor (Pierburg 2V type) -
idle speed and mixture adjustment
Fuel and exhaust systems - carburettor 4A•15
4A
25.8a Disconnecting the crankcase
ventilation . . .
24.2 Fast idle speed adjustment - Weber
2V TLD carburettor
A Fast idle cam
B Adjustment screw on middle step of cam21.4 Fast idle speed adjustment - Pierburg
2V carburettor
Screw (arrowed) should rest on lowest (6th)
step of cam
Caution: Refer to the
precautions in Section 1 before
proceeding.

bracket (see illustration).
12Lift the inlet manifold from the cylinder
head, and recover the gasket (see
illustration).
13If desired, the carburettor can be removed
from the inlet manifold by unscrewing the
securing nuts or screws. Refer to the relevant
Section describing carburettor removal and
refitting. Recover the gasket.
Refitting
14Refitting is a reversal of removal bearing
in mind the following points.
15Ensure that all mating faces are clean.
16Renew the gasket(s), and apply a bead of
sealant at least 5.0 mm (0.2 in) wide around
the central coolant aperture on both sides of
the manifold-to-cylinder head gasket.
17Tighten the manifold securing nuts and
bolts progressively to the specified torque,
ensuring that the engine lifting bracket is in
place.
18Make sure that all hoses, pipes and wires
are correctly reconnected, and if the fuel
supply hose was originally secured with a
crimped type clip, discard this and use a new
worm drive clip on refitting.
19On completion, refill the cooling system,
adjust the throttle cable and check and if
necessary adjust the idle speed and mixture.
DOHC models
Removal
20Disconnect the battery negative lead.
21Partially drain the cooling system.
22Remove the air cleaner.
23Disconnect the coolant hoses from the
thermostat housing and the inlet manifold,
noting their locations to assist with refitting.
24Disconnect the fuel supply and return
hoses from the carburettor. Plug their ends to
minimise petrol spillage.
25Release the coolant hose from the bracket
under the automatic choke housing.
26Disconnect the HT leads from the spark
plugs, and move them to one side.
27Disconnect all relevant wiring and vacuum
pipes from the carburettor, thermostat
housing and inlet manifold, noting the
locations as an aid to refitting.
28Disconnect the crankcase breather hose
from the inlet manifold. 29Disconnect the throttle cable from the
throttle linkage.
30Make a final check to ensure that all
relevant wires, pipes and hoses have been
disconnected to facilitate removal of the
manifold.
31Unscrew the ten bolts and two nuts
securing the manifold to the cylinder head.
32Lift the manifold clear of the cylinder
head. Recover the gasket.
33Recover the two plastic spark plug
spacers from the recesses in the cylinder
head.
34If desired, the carburettor can be removed
from the manifold by unscrewing the securing
screws. Refer to the carburettor removal and
refitting Sections as necessary.
Refitting
35Refitting is a reversal of removal, bearing
in mind the following points.
36Ensure that all mating faces are clean.
37Ensure that the spark plug spacers are in
position in the cylinder head recesses before
refitting the manifold.
38Renew all gaskets.
39Tighten all manifold securing nuts and
bolts progressively to the specified torque.
40Make sure that all hoses, pipes and wires
are securely reconnected in their original
positions.
41On completion, refill the cooling system.
Check the adjustment of the throttle cable.
Check, and if necessary adjust, the idle speed
and mixture.
CVH models
Removal
42Proceed as described in paragraphs 1 to
3 inclusive.
43Disconnect the coolant hoses from the
automatic choke, thermostat housing and
inlet manifold, noting their locations for use
when refitting.
44Disconnect the fuel supply hose at the
carburettor and plug the end to minimise
petrol spillage.
45Disconnect all relevant wiring and vacuum
pipes from the carburettor, thermostat
housing and inlet manifold, noting the
locations as an aid to refitting.
46Disconnect the throttle cable from the
throttle linkage.
47Unbolt the dipstick tube from the inlet
manifold and withdraw the dipstick and
dipstick tube from the cylinder block.
48Unscrew the seven nuts securing the
manifold to the cylinder head, then lift the
manifold from the cylinder head, and recover
the gasket.
49If desired, the carburettor can be removed
from the manifold by removing the securing
screws. Recover the insulator block (see
illustrations).
50The carburettor intermediate plate can be
removed from the manifold by unscrewing the
three securing screws. Recover the gasket.
51If necessary, the thermostat and housing
can be removed from the manifold.
4A•16Fuel and exhaust systems - carburettor
25.8b . . . and brake servo vacuum hoses
from the inlet manifold - SOHC models25.12 Lifting the inlet manifold from the
cylinder head - SOHC models
25.49b . . . and the insulator block from the
inlet manifold - CVH models25.49a Removing the carburettor . . .
25.11 Rear engine lifting bracket location -
SOHC models

Refitting
52Refitting is a reversal of removal, bearing
in mind the following points.
53Ensure that all mating faces are clean and
renew the gasket(s).
54Tighten the manifold securing nuts
progressively to the specified torque.
55Make sure that all hoses, pipes and wires
are correctly reconnected, and if the fuel
supply hose was originally secured with a
crimped type clip, discard this and use a new
worm drive clip on refitting.
56On completion, refill the cooling system,
adjust the throttle cable and check and if
necessary adjust the idle speed and mixture.
Removal
1Disconnect the battery negative lead.
2Remove the air cleaner and pull the hot air
pick-up pipe from the exhaust manifold hot air
shroud.
3Remove the securing screws (1 screw on
DOHC models, 2 screws on SOHC models, 3
screws on CVH models) and lift the hot air
shroud from the manifold. Note the position of
the coolant hose bracket which is secured by
the front hot air shroud securing screw on
SOHC models (see illustration).
4Unscrew the securing nuts, and disconnect
the exhaust downpipe from the manifold (see
illustration). Recover the gasket. Support the
exhaust downpipe from underneath thevehicle, with an axle stand for example, to
avoid placing unnecessary strain on the
exhaust system.
5Disconnect the HT leads from the spark
plugs, if necessary identifying them for
locations, and place them to one side out of
the way.
6Unscrew the eight securing nuts, noting the
location of the front engine lifting bracket
secured by the front two nuts on SOHC
models, and lift the manifold from the cylinder
head. Recover the gasket(s) where applicable
(see illustrations).
Refitting
7Refitting is a reversal of removal, bearing in
mind the following.
8Ensure that all mating faces are clean, and
renew all gaskets. Note that on CVH models,
no gasket is fitted between the manifold andcylinder head in production, but a gasket
must be used when refitting. Where
applicable, remove the plastic spacer from the
rear manifold stud before fitting the gasket
(see illustrations).
26Exhaust manifold - removal
and refitting
Fuel and exhaust systems - carburettor 4A•17
4A
26.6a Unscrew the exhaust manifold
securing nuts . . .
26.8c Fitting the exhaust manifold -
DOHC models26.8b Remove the plastic spacer (arrowed)
before fitting exhaust manifold gasket -
CVH models26.8a Exhaust manifold gaskets in position
on cylinder head - DOHC models
26.6d SOHC models have separate
manifold gaskets for each exhaust port26.6c . . . and lift off the exhaust manifold -
SOHC models26.6b . . . noting the location of the front
engine bracket . . .
26.4 Unscrewing an exhaust downpipe
securing nut26.3 Exhaust manifold hot air shroud
showing securing screws (1 and 3) and
coolant hose clip (2) - SOHC models

9Tighten the manifold securing nuts
progressively to the specified torque, and
similarly tighten the exhaust downpipe
securing nuts. Do not forget to fit the engine
lifting bracket on SOHC models.
10Ensure that the HT leads are reconnected
to their correct cylinders.
Inspection
1The exhaust system should be examined for
leaks, damage, and security at regular
intervals. To do this, apply the handbrake, then
start the engine and allow it to idle. Lie down on
each side of the vehicle in turn and check the
full length of the exhaust system for leaks,
while an assistant temporarily places a wad of
cloth over the tailpipe. If a leak is evident, stop
the engine and use a proprietary repair kit to
seal it. If an excessive leak or damage is
evident, renew the relevant section of the
exhaust system. Check the rubber mountings
for deterioration and renew if necessary.
Removal
2To remove the exhaust system, jack up the
front and rear of the vehicle and support on
axle stands (see “Jacking and Vehicle
Support”).
3If desired, the exhaust downpipe can be
removed independently of the remainder of
the system, and similarly the main part of the
system can be removed, leaving the
downpipe in place.
4To remove the downpipe, unscrew the
securing nuts and disconnect the downpipe
from the manifold. Recover the gasket.
Unscrew the two nuts and bolts, and separate
the downpipe flanged joint from the remainder
of the system. Withdraw the downpipe (see
illustrations).
5To remove the main section of the exhaust
system leaving the downpipe in place,
unscrew the two securing nuts and bolts and
separate the flanged joint from the downpipe.
Unhook the rubber mountings and withdraw
the system from underneath the vehicle. The
number and type of rubber mountings variesaccording to model (see illustrations). If
necessary to avoid confusion, note how the
mountings are fitted to enable correct
refitting. Note that on P100 models the
system must be manipulated to pass over the
rear axle.
Refitting
6Refitting is a reversal of removal, but ensure
that all mating faces are clean, and fit a new
gasket between the downpipe and manifold
(see illustration). Do not fully tighten the joint
27Exhaust system - inspection,
removal and refitting
4A•18Fuel and exhaust systems - carburettor
27.4a Exhaust downpipe-to-manifold
flanged joint viewed from underneath
vehicle27.5a Rear exhaust section mounting -
Hatchback model
27.9a Cutting point when fitting a service replacement exhaust system section - Saloon,
Hatchback and Estate models
X = 1639 mm for all models up to 1987 except 1.3 and 1.6 litre Hatchback
X = 1681 mm for 1.3 and 1.6 litre Hatchback models up to 1987
X = 2063 mm for all models from 1987
27.6 Fit a new downpipe-to-manifold
gasket27.5b Rear exhaust mounting - P100 model
27.4b Exhaust downpipe-to-main system
flanged joint

fittings until the system is in position and
correctly aligned in its mountings under the
vehicle. Ensure that no part of the exhaust
system is closer than 25.0 mm (1.0 in) to the
underbody.
7Service replacement exhaust systems are
available in three sections; downpipe, centre
section and rear section. The service replace-
ment sections fit together using socket joints,
therefore the centre section of a production
exhaust system cannot be renewed without
also renewing the rear section.
8To renew the centre and/or rear section(s)
of the exhaust system, first remove the main
system as described in paragraph 5.9To fit a service replacement rear section to
a production system, use a hacksaw to cut
through the pipe at the applicable point
shown (see illustrations). Apply exhaust
sealant to the mating surfaces of the two
sections, then push the two sections together
and fit a U-bolt clamp to the centre of the
joint. Do not fully tighten the U-bolt clamp
nuts until the system is in position and
correctly aligned in its mountings under the
vehicle.
10To renew a service replacement section,
unscrew the nuts and remove the U-bolt
clamp from the joint. Tap around the joint to
break the seal, and separate the centre andrear sections. Ensure that the joint mating
surfaces are clean, then apply exhaust
sealant, push the new section onto the
remaining section, and fit the U-bolt clamp to
the centre of the joint. Do not fully tighten the
U-bolt clamp nuts until the system is in
position and correctly aligned in its mountings
under the vehicle.
Refer to Chapter 5, Section 22 (see
illustration).
28Vacuum valves, ported vacuum
switches and fuel traps -
removal and refitting
Fuel and exhaust systems - carburettor 4A•19
4A
28.1 Low vacuum enrichment ported vacuum switch location in
inlet manifold - model with Weber 2V carburettor27.9b Cutting point when fitting a service replacement exhaust
system section - P100 models
X = 226 mm

4A•20Notes