28Fuel injectors (except Multec
system) - removal and refitting
3
Note:Refer to Section 2 before proceeding.
New O-rings must be used when refitting the
injectors. Where applicable, a tachometer and
an exhaust gas analyser will be required to
check the idle mixture on completion
Removal
SOHC models
1Disconnect the battery negative lead.
2Unscrew the union nut, and disconnect the
brake servo vacuum hose from the inlet
manifold.
3Remove the idle speed adjuster, complete
with hoses, referring to Section 22 if
necessary.4Disconnect the vacuum pipe from the top
of the fuel pressure regulator.
5Disconnect the wiring harness housing from
the fuel injectors, and move it to one side,
taking care not to strain the wiring. Pull up on
the wiring harness housing, and compress the
wiring plug retaining clips to release the
harness housing from the injectors.
6Remove the four bolts from the brackets
securing the fuel rail to the inlet manifold, then
lift the fuel rail complete with fuel injectors
sufficiently to enable the injector(s) to be
removed (see illustrations). Take care not to
strain the fuel hoses.
7To remove an injector from the fuel rail,
prise out the metal securing clip using a
screwdriver, then pull the injector from the fuel
rail (see illustrations).
Refitting
8Overhaul of the fuel injectors is notpossible, as no spares are available. If faulty,
an injector must be renewed.
9Begin refitting by fitting new seals to both
ends of each fuel injector (see illustration).
Even if only one injector has been removed,
new seals should be fitted to all four injectors.
10Refitting is a reversal of removal, ensuring
that all hoses, pipes and wires are correctly
reconnected.
11On completion, where applicable, check
and if necessary adjust the idle mixture, as
described in Section 20.
DOHC models
Removal
12Disconnect the battery negative lead.
13Loosen the clamp screw securing the air
trunking to the left-hand end of the air mass
meter.
14Using an Allen key or hexagon bit, unscrew
the four bolts securing the air box to the throttle
body. Lift the air box from the throttle body,
and disconnect the hose from the base of the
air box, then withdraw the air box.
15Position a wad of rag beneath one of the
fuel hose unions on the fuel rail, to absorb the
fuel that will be released as the union is
disconnected.
16Slowly loosen the fuel hose union to
relieve the pressure in the fuel line, then
disconnect the hose from the fuel rail. Be
prepared for fuel spillage, and take adequate
fire precautions. Plug the end of the fuel hose,
to prevent dirt ingress and further fuel leakage.
17Repeat paragraphs 15 and 16 for the
remaining fuel hose-to-fuel rail union.
18Disconnect the two breather hoses from
the rear of the camshaft cover. Disconnect the
larger hose from the throttle body, and
remove the hose completely.
19Disconnect the vacuum pipe from the top
of the fuel pressure regulator.
20Disconnect the wiring plug from the air
mass meter. Recover the sealing ring.
21Disconnect the wiring plug from the
throttle position sensor.
22Slide the end of the throttle cable from the
throttle valve lever on the throttle body, then
unbolt the cable bracket from the inlet
manifold, and move it to one side (see
illustration).
Fuel and exhaust systems - fuel injection models 4B•13
28.6C . . . and lift the fuel rail from the inlet
manifold (inlet manifold removed for
clarity) - SOHC model
28.22 Throttle cable bracket securing
bolts (arrowed) - DOHC model28.9 Fit new seals to the injectors
28.7B . . . then pull the injector from the
fuel rail - SOHC model28.7A Withdraw the securing clip . . .
28.6B . . . and inner fuel rail securing
bolts . . .28.6A Remove the outer . . .
4B
23Disconnect the wiring harness housing
from the fuel injectors, and move it to one
side, taking care not to strain the wiring. Pull
up on the wiring harness housing, and
compress the wiring plug retaining clips to
release the housing from the injectors.
24Unscrew and remove the two fuel rail
securing nuts, and withdraw the fuel rail
complete with fuel injectors from the inlet
manifold. Note the position of the earth leads
on the fuel rail securing studs (see
illustration).
25To remove an injector from the fuel rail,
prise out the metal securing clip using a
screwdriver, then pull the injector from the fuel
rail
Refitting
26Refitting is as described in paragraphs 8
to 11 inclusive.
29Fuel injector (Multec system)
- removal and refitting
3
Removal
1Depressurise the fuel system (see Sec
tion 8).
2Remove the air box (see Section 5).
3Disconnect the battery earth lead.
4Disconnect the wiring plug from the fuel
injector (see illustration).
5Undo the Torx-type screw (size TX 20)
securing the fuel injector retainer to the top ofthe throttle body, remove the retainer and lift
out the injector (see illustration). Remove
and discard the injector sealing rings.
Refitting
6Refitting is the reverse of the removal
procedure, noting the following points.
a)Always renew both sealing rings; apply a
smear of grease to each to ease injector
refitting (see illustration).
b)Refit the injector so that its wiring
terminals point to the rear of the vehicle;
locate the edge of the retainer securely in
the groove at the top of the injector.
c)Apply a few drops of a thread-locking
compound to the screw threads, then
tighten it carefully to the specified torque
wrench setting.
d)Switch on the ignition and check carefully
for signs of fuel leaks; if any signs of
leakage are detected, the problem must
be rectified before the engine is started.
30Fuel injector (Multec system)
- testing
3
1A simple test of the injector’s windings is
possible for those who have a multi-meter of
sufficient sensitivity. First disconnect the
injector wiring plug as described in Section 29,
then connect the meter (set to the appropriate
resistance scale) across the injector’s
terminals and note the reading obtained.
2On C18 NZ engines, the reading should be
within the specified tolerance; similar results
can be expected on C16NZ, C16NZ2, and
X16 SZ engines.
3If the reading differs significantly from the
specified value, indicating either shorted or
open circuit windings, the injector must be
renewed.
4Note that this is only a test of the injector’s
electrical condition; it does not test its spray
pattern or performance. If the injector is
thought to be faulty it is always worth trying a
well known injector-cleaning treatment. If this
fails, the vehicle must be taken to a Vauxhall
dealer for full testing on the special test
equipment.
31Throttle body (except Multec
system) - removal and refitting
3
Note:Refer to Section 2 before proceeding. A
new throttle body gasket must be used on
refitting
SOHC
Removal
1Disconnect the battery negative lead.
2Loosen the clamp screws securing the air
trunking to the throttle body and the airflow
meter, then withdraw the air trunking.
3Loosen the clamp screw, and disconnect
the idle speed adjuster hose from the throttle
body.
4Disconnect the camshaft cover breather
hose from the throttle body.
5Disconnect the coolant hoses from the
throttle body. Be prepared for coolant
spillage, and clamp or plug the open ends of
the hoses, to prevent further coolant loss.
6Disconnect the wiring plug from the throttle
position sensor.
7Release the securing clip, then disconnect
the throttle cable end balljoint from the throttle
valve lever.
8Slide the throttle cable grommet from the
bracket on the inlet manifold, then unhook the
throttle return spring from the bracket (see
illustration).
9Make a final check to ensure that all relevant
hoses and wires have been disconnected and
moved clear of the throttle body.
4B•14Fuel and exhaust systems - fuel injection models
28.24 Earth leads secured to fuel rail stud
(arrowed) - DOHC model29.5 Unscrewing the injector retainer Torx
screw
31.8 Unhook the throttle return spring
from the bracket on the inlet manifold
(inlet manifold removed for clarity)29.6 Renew injector sealing rings
(arrowed)
29.4 Disconnecting the fuel injector wiring
plug - Multec systems
Refitting
5Refitting is a reversal of the removal
procedure, ensuring that the wiring plugs are
correctly reconnected and that the unit is
located securely.
36Knock sensor and module
(X16 SZ models) - removal
and refitting
3
Removal
1The knock sensor fitted to the X16 SZ
engine is located on the cylinder block below
the inlet manifold, between cylinders 2 and 3.
2Disconnect the battery negative lead.
3Remove the wiring and unscrew the unit
from the block.
4The module and control unit are located on
the left-hand side of the engine compartment
behind the battery. To remove, disconnect the
wiring multiplug and remove the retaining
bolts (see illustration).
5There is no provision for testing the knock
sensor or module without dedicated Vauxhall
test equipment. Check for external damage
and replace if necessary.
Refitting
6Refitting is a reversal of the removal
procedure, ensuring that the wiring plugs are
correctly reconnected and that the units are
located securely.
37Knock sensor (Simtec
system) - removal and refitting
3
Removal
1Disconnect the battery negative lead.
2Disconnect wiring harness plug, from inlet
air temperature sensor and wiring harness
plug, from hot mass air flow meter.
3Remove crankcase ventilation hoses.
4Remove coolant hoses from air inlet hoses,
hot film mass air flow meter complete with air
inlet hoses, from upper part of air cleaner and
throttle body.5Press retaining clip for 1st and 4th cylinder
injectors in plug strip (with screwdriver)
towards fuel distributor pipe - lifting plug strip
at the same time. On the underside of the plug
strip there are a total of 6 plug connections, 4
of which are for the injectors.
6Disconnect wiring harness plug for knock
sensor from the plug strip.
7Connect a 1 metre length of separate cable
to knock sensor wiring harness plug (note
routing).
8Remove knock sensor from cylinder block
(see illustration).
9Disconnect knock sensor cable from
separately attached cable, separate cable
remains in engine compartment.
Refitting
10Refitting is a reversal of removal, but note
the following.
11Before refitting ensure that the sensor is
spotlessly clean. Clean the entire contact
surface of the sensor must lie directly on the
cylinder block. Do not use any form of
washers.
12Carefully refit sensor into the block.
Tighten to the correct torque.
13Guide knock sensor cable between ridges
on inlet manifold using separate cable -
ensure correct routing.
14Remove the cable.
15Insert the wiring harness plug for the
knock sensor, into the plug strip.
16Correctly align the spring clips for theinjectors as they may prevent engagement of
the plug strip. Correct contact between the
plug strip and the injector is essential.
17When connecting plug strip, an audible
‘click’ should be heard.
18Ensure that hoses are in good condition
and installed securely with the two clamps.
38Inlet manifold (SOHC without
Multec) - removal and refitting
3
Note:Refer to warning in Section 2, before
proceeding. Use a new gaskets when refitting.
Removal
1Disconnect the battery negative lead.
2Remove the idle speed adjuster and its
hoses, referring to Section 22, if necessary.
3Release the securing clip, then disconnect
the throttle cable and balljoint from the throttle
valve lever. Slide the throttle cable grommet
from the bracket on the inlet manifold, and
move the throttle cable to one side out of the
way.
4Loosen the clamp screw and disconnect
the air trunking from the throttle body.
5Unscrew the union nut and disconnect the
brake servo vacuum hose from the inlet
manifold(see illustration).
6Disconnect the camshaft cover breather
hose from the throttle body.
7Disconnect the coolant hoses from the
throttle body. Be prepared for coolant
spillage, and clamp or plug the open ends of
the hoses, to prevent further coolant loss.
8Disconnect the wiring plug from the throttle
position sensor.
9Disconnect the vacuum pipe from the top
of the fuel pressure regulator.
10Disconnect the wiring harness housing
from the fuel injectors and move it to one side,
taking care not to strain the wiring. Pull up on
the wiring harness housing, and compress the
wiring plug retaining clips to release the
harness housing from the injectors.
11Disconnect the fuel hoses from the fuel
rail. Be prepared for fuel spillage, and take
adequate fire precautions. Clamp or plug the
open ends of the hoses, to prevent dirt
ingress and further fuel leakage.
Fuel and exhaust systems - fuel injection models 4B•17
38.5 Disconnecting the brake servo
vacuum hose -
SOHC models37.8 Knock sensor and wiring
(Simtec system)
1 Sensor2 Securing bolt
36.4 Knock sensor and module (X16 SZ models)
1 Sensor2 Module3 Sensor securing bolt
4B
12Unscrew and remove the top alternator
mounting nut and bolt.
13Make a final check to ensure that all
relevant hoses, pipes and wires have been
disconnected.
14Unscrew the securing nuts, and withdraw
the manifold from the cylinder head. Recover
the gasket (see illustrations).
15It is possible that some of the manifold
studs may be unscrewed from the cylinder
head when the manifold securing nuts are
unscrewed. In this event, the studs should be
screwed back into the cylinder head once the
manifold has been removed, using two
manifold nuts locked together.
16If desired, the ancillary components can
be removed from the manifold, referring to the
relevant Chapter.
Refitting
17Refitting is a reversal of removal,
remembering the following points.
18Where applicable refit any ancillary
components to the manifold, with reference to
relevant Sections of Chapters 4A or 4B.
19If the alternator mounting bracket has
been unbolted from the manifold, refit it
before refitting the manifold, as access to the
securing bolt is extremely limited once the
manifold is in place.
20Refit the manifold using a new gasket,
and tighten the securing nuts to the specified
torque.
21Ensure that all relevant hoses, pipes and
wires are correctly reconnected.
22On completion, check and if necessary
top-up the coolant level, (Chapter 3).
23Check and if necessary adjust the throttle
cable free play, as described in Chapters 4A
or 4B, as applicable.
24If any of the fuel system components have
been disturbed or renewed, check and if
necessary adjust the idle mixture, as
described in Chapters 4A or 4B, as applicable.
39Inlet manifold (SOHCwith
Multec) - removal and refitting
3
Removal
1Depressurise the fuel system Section 8).
2Remove the air box (see Section 5).
3Disconnect the battery negative lead.
4Either remove the throttle body assembly
(see Section 32), or disconnect the throttle
cable, wiring, fuel and vacuum hoses and
pipes to allow the manifold to be removed
with the throttle body.
5Drain the cooling system (see Chapter 3).
6Continue as described in Chapter 4A,
Section 26, paragraph 4 onwards.
Refitting
7Refitting is the reverse of the removal
procedure; renew all gaskets and seals
disturbed.
40Inlet manifold (DOHC
models) - removal and
refitting
3
Removal
1Disconnect the battery negative lead.
2Disconnect the wiring plug from the air
mass meter. Recover the sealing ring.
3Loosen the clamp screw securing the air
trunking to the right-hand end of the air mass
meter.
4Using an Allen key or hexagon bit, unscrew
the four bolts securing the air box to the
throttle body. Lift the air box from the throttle
body, and disconnect the hose from the base
of the air box then withdraw the air box/air
mass meter assembly.
5Disconnect the wiring plug from the throttle
position sensor.
6Slide the throttle cable end from the throttle
valve lever. Then pull the cable end grommet
from the bracket on the inlet manifold and
move the throttle cable to one side out of the
way.
7Disconnect the two breather hoses from the
rear of the camshaft cover. Disconnect the
larger hose from the throttle body, and
remove the hose completely.
8Position a wad of rag beneath one of the
fuel hose unions on the fuel rail, to absorb the
fuel that will be released as the union is
disconnected.
9Slowly loosen the fuel hose union, to
gradually relieve the pressure in the fuel feed
line, then disconnect the hose from the fuel
rail. Be prepared for fuel spillage, and take
adequate fire precautions. Plug the end of the
fuel hose, to prevent dirt ingress and further
fuel leakage.
10Repeat paragraphs 9 and 10 for the
remaining fuel hose-to-fuel rail union.
11Disconnect the vacuum pipe from the top
of the fuel pressure regulator.
12Disconnect the wiring harness housing
from the fuel injectors and move it to one side,
taking care not to strain the wiring. Pull up on
the wiring harness housing, and compress the
wiring plug retaining clips to release the
housing from the injectors.
13Unscrew the union nut, and disconnectthe brake servo vacuum hose from the left-
hand side of the inlet manifold (see
illustration).
14Unscrew the retaining nut, and remove
the fuel hose bracket from the left-hand side
of the throttle body.
15Unscrew the securing nuts, and
disconnect the earth leads from the fuel rail
securing studs at either end of the fuel rail.
16Unscrew the securing bolt, and remove
the cable/hose bracket from the left-hand end
of the inlet manifold.
17Remove the idle speed adjuster, as
described in Section 22.
18Unscrew and remove the top alternator
mounting nut and bolt.
19Make a final check to ensure that all
relevant hoses, pipes and wires have been
disconnected.
20Unscrew the securing nuts, and withdraw
the manifold from the cylinder head. Recover
the gasket.
21It is possible that some of the manifold
studs may be unscrewed from the cylinder
head when the manifold securing nuts are
unscrewed. In this event, the studs should be
screwed back into the cylinder head once the
manifold has been removed, using two
manifold nuts locked together.
22If desired, the ancillary components can
be removed from the manifold, with reference
to the relevant Sections of Chapters 4A or 4B.
Refitting
23Refitting is a reversal of the removal
procedure.
4B•18Fuel and exhaust systems - fuel injection models
38.14A Unscrew the securing nuts
40.13 Brake servo vacuum hose
connection at inlet manifold (arrowed) -
DOHC models
38.14B ...and withdraw the inlet manifold -
SOHC models