Page 161
Fuel Injection
240-15
CAUTION
Use only a digital voltmeter, an LED test light or an LED injector tester. Use of an analog VOM or incandescent test light
may damage the control unit.
/'
Fig. 16. Fuel rail is common fuel supply and mounting for all four injectors.
gents. If the problem is serious, a Saab dealer or other
qualified repair shop has specialized injector cleaning equipment.
A second problem is old and cracked O-rings. They allow
unmeasured air to enter the engine. Since the air is unmeasured, additional fuel is not injected and the mixture is leaned.
The LH control unit will usually adapt itself to this extra air, but
a symptom of this problem is increased fuel consumption. The
injectors must be removed as later described under Component Replacement.
NOTE
Damaged injector O-rings are just one of many possible causes of increased fuel consumption. For more infonnation see
200 Engine-General.
To test injectors
NOTE
The infonnation below is an electrical test only. The test does
not check the spray patterns or fuel supply to the injectors. A
Saab dealer or other qualified repair shop can perfonn such a
test as part of the injector cleaning procedure.
1. Disconnect a harness connector from an injector and
connect to it an LED test light, an injector tester, or a
digital voltmeter across the connector. See Fig. 17.
When the engine is cranked, the LED should flash or
the following voltage should be present:
Injector cranking voltage (approximate VDC)
• engine temp. 32°F
• engine temp. 68°F
• engine temp. 176°F
1 volt
0.6 volt
0.3 volt
_________.
B~_______.i
Fig. 17. Special LED test light connected across fuel injector connector for voltage test. Simple LED test light or digital VOM can
also be used.
NOTE
If the engine runs but you think one injector is bad, place a
screwdriver or an automotive stethoscope on the injector.
There should be a buzzing or vibration as the engine runs. If
the injector is not buzzing, check for voltage to the injector and
check its resistance as described below. If the injector is buzzing, very briefly unplug the hamess connector from the injector with the engine running. If the injector is working correctly,
there should be a noticeable rpm drop.
2. If the light doesn't flash or there is no voltage, check for
power to the injector. There should be battery voltage
(+) at the blue/red wire of each injector connector with
the ignition key on. See Fig. 18. If not, check the wiring
to the injector using the wiring diagrams listed in 371
Wiring Diagrams, Fuses and Relays.
NOTE
If there is positive (+) battery voltage as described in step 2,
but there was no response through the LED or voltmeter in
step 1, check the wire from the control unit to the injectors. If
no wiring faults can be found, the ground signal from the control unit is missing. See Electrical Checks and Component
Testing for additional electrical tests.
3. If power is present as described in the above step, unplug the injector connectors and check the injector resistance. Replace the injector if the resistance is incorrect.
Injectors
• resistance
16 ohms at 68°F (20°C)
ELECTRICAL CHECKS AND COMPONENT TESTING
Page 162
240-16
Fuel Injection
pared to the oxygen outside the exhaust pipe. The bigger the
differential, the greater the output voltage. When the mixture
is rich, there is very little oxygen in the exhaust (high output
voltage). When the mixture is lean, there is an excess of oxygen in the exhaust (low output voltage).
Fig. 18. Checking power to injector with ignition on. Check at red-blue
wire of connector.
NOTE
Injector resistance will vary slightly depending on temperature. In general, the range should be between 10 and 20
ohms.
4. If no faults are found up to this point, check the pulsetime regulation function of the control unit. Peel back
the rubber boot from the injector connector and connect a voltmeter to the wires in the connector. Start the
engine. Check that the voltage decreases as the engine warms up. The values given below are approximate.
The oxygen sensor must be at a temperature of at least
600°F to generate voltage, so it is electrically heated to help it
reach operating temperature more quickly. The oxygen sensor is checked by seeing if it generates a voltage when the engine is idling at normal operating temperature.
To test oxygen sensor
Injector warm-up enrichment voltage (VDC)
• engine temp. 32°F
• engine temp. 68°F
• engine temp. 176°F
Fig. 19. Location of oxygen sensor (arrow) on turbo model (in exhaust
manifold). On non-turbo model, the oxygen sensor is mounted in the front exhaust pipe, near the steering rack.
1 volt
0.6 volt
0.3 volt
1. Disconnect the sensor's single black wire (sensor signal wire). See Fig. 20.
If the voltage readings are incorrect, check the temperature
sensor as described above. Also check the CO reading and
the air mass meter burn off function. If these are OK, then either the wiring to the control unit or the control unit itself is
faulty. Check the control unit inputs and wiring by making the
electrical checks described below under LH Control Unit.
Oxygen Sensor
The oxygen sensor monitors the exhaust gas and provides
the LH control unit with feedback about the air-fuel ratio and
combustion efficiency. Using this information, the control unit
continuously adjusts the air-fuel mixture to ensure optimum
driveability and exhaust emissions.
The oxygen sensor is mounted in the exhaust system. See
Fig. 19. The oxygen sensor produces a small voltage (0-1
volt) based on the oxygen content in the exhaust gas as com-
ELECTRICAL CHECKS AND COMPONENT TESTING
Fig. 20. Oxygen sensor wiring connectors are located on right (passenger) inner fender well, just above battery.
Page 163
Fuel Injection
240-17
2. Connect the positive lead of a voltmeter to the black
wire corning 'from the sensor and connect the negative
meter lead to chassis ground. See Fig. 21. Start the car
and let it idle. The oxygen sensor should start to produce a fluctuating voltage within a short period.
Fig. 22. Oxygen sensor heating coil resistance being measured
(shown schematically).
87672
If the oxygen sensor doesn't produce voltage, and the preheater circuit is OK, replace the sensor.
Fig. 21. Oxygen sensor output voltage being checked (shown schematically). Sensor should be installed and the engine should
be running.
Tightening Torque
• Oxygen sensor
40 Nm (29 ft-Ib)
Oxygen sensor
• voltage at idle
0.4 to 1 volt
NOTE
To further check sensor response to lean and rich mixtures,
slightly open the oil filler cap to create an air leak, or pull the
vacuum hose off of the fuel pressure regulator to increase fuel
pressure.
3. If the sensor does not emit a fluctuating voltage, turn
the engine off and check the sensor's preheater circuit.
Disconnect the two-wire connector and check for battery voltage at the connector with the engine running. If
voltage is not present, check the wiring to the preheater
and check the preheater fuse. If voltage is present,
check the preheater coil resistance. See Fig. 22. If any
faults are found, replace the sensor.
NOTE
Coat the oxygen sensor threads with an anti-seize compound
before installation. Do not get the compound on the sensor tip.
This can damage the sensor.
Automatic Idle Control (AIC) System
The AIC system maintains idle speed through the AIC idle
control valve. See Fig. 23. The system compensates for engine load and engine operating conditions, so periodic adjustment of the idle speed is unnecessary. The AIC valve is
controlled by the LH control unit.
NOTE
On 1986 through 1988 models, the preheater fuse is in-line, in
the engine compartment on the right-hand side fender. On
1989 and later cars, the fuse is in the main fuse/relay panel
(position no. 1). On 1985 models, the preheater is not fuse
protected.
L
Oxygen sensor
• preheater resistance
_
---_..- -
87674-$ 1/138
- - - - - - - - - -
Fig. 23. Ale valve.
approx. 4 ohms
ELECTRICAL CHECKS AND COMPONENT TESTING
Page 164
240-18
Fuel Injection
The LH control unit monitors engine rpm and other operating conditions such as air conditioning and automatic transmission loads, and then sends an electrical signal to open or
close the valve. This changes the amount of air that bypasses
the closed throttle valve.
NOTE
If you suspect an intermittent fault, lightly tap the valve while
you are testing resistance.
LH 2.4
NOTE
There are three different idle control valves used on the cars
covered by this manual, depending on the fuel system. These
valves operate differently and are not interchangeable between fuel systems.
On LH 2.4 and LH 2.4.2 fuel injection, the AIC function is
completely adaptive. The control unit remembers how far the
valve was open the last time the engine was at idle and reverts
to this as a base setting. In addition, the valves used on these
models have a limp-home feature that maintains a fixed idle
speed in the event of an AIC valve failure. This idle speed is
approximately 1,200 rpm on cars with LH 2.4 and 850 rpm on
cars with LH 2.4.2.
Before proceeding with troubleshooting an idle problem,
check that the throttle position sensor is working correctly as
described earlier under Throttle Position Sensor. On cars
with high mileage, enough residue and dirt may collect on the
throttle valve plate and bore to restrict air flow and affect the
AIC system. remove the AIC valve and the air intake duct from
the throttle housing. Clean both the AIC valve and the throttle
plate and bore. Reinstall the valve and duct and run the engine to check idle.
_ _ _ _ _8_7_675
Fig. 24. Idle control valve terminals.
Table j. Ale Valve Resistance
Fuel System
Test terminals
LH 2.2
1and2
2 and 3
1 and 3
I
Resistance (ohms)
~
_I 20±2
. ---_.~--_.----
I 40±4
- ---t
LH 2.4
LH 2.4.2
1 and 2
1 and 2
2 and 3
!
8±2
-r-I
I
10-15
10-15
I
NOTE
On models with LH 2.2 fuel injection, the base idle may need
to be reset after this procedure. See LH Fuel Injection Adjustments as described below.
I
3. With the valve's harness connector disconnected,
check for voltage at the blue/red wire in the connector.
When the ignition is turned on there should be approximately battery voltage.
To test Ale system
1. With the engine running, check that the idle control
valve is buzzing. On cars with air conditioning (AlC) or
automatic transmission, turn on the AlC or shift the car
into drive. Idle should remain steady or increase slightly.
2. If the valve is not buzzing, or if idle decreases, stop the
engine and disconnect the harness connector from the
valve. Check the resistance of the valve across its terminals. Fig. 24 shows the valve terminals. Table j lists
the test terminals and results. If resistance is incorrect,
replace the valve. If resistance is OK, test for power to
the valve as described below.
NOTE
On models with LH 2.2 fuel injection, the voltage will be momentary-only for as long as the fuel pump relay is closed. To
get a constant voltage supply, run the engine.
4. If there is no voltage at the connector, check the wiring
to the valve's connector. See 371 Wiring Diagrams,
Fuses and Relays.
NOTE
On LH 2.2, the Ale valve receives positive (+) battery voltage
from the fuel pump relay. On LH 2.4 and LH 2.4.2, the valve
receives voltage from the system relay.
ELECTRICAL CHECKS AND COMPONENT TESTING
Page 165
Fuel Injection
5. If voltage is present as described in step 3, check the
wiring between the control unit and the valve and fix
any breaks. If no wiring faults are found, check the LH
control unit signal to the AIC valve. If the signal to the
valve is as specified, the AIC valve is probably faulty
and should be replaced.
240-19
earlier. Remove the control unit, unplug the connector, and
make tests from the back of the connector to avoid damaging
connector terminals. See Fig. 25. Control unit connector terminals are shown in Fig. 26. Table k and Table I list the tests
and correct test results.
NOTE
• On cars with LH 2.2, the AIC valve control signal can be
checked using a duty cycle meter (or dwell meter) as described below under LH Fuel Injection Adjustments.
• On cars with LH 2.4 and LH 2.4.2, the AIC valve control signal can be checked by making the electrical tests outline below under LH Control Unit.
There are some additional inputs to the control unit that affect idle speed (i.e. throttle position, AlC-on signals, and AlT
Drive position). To check these signals, make the electrical
tests described below under LH Control Unit.
Fig. 25. For access to back of connector terminals when testing, disconnect connector and remove rubber gasket.
LH Control Unit
LH 2.2
13 12 11 10 9
The following voltage and continuity tests will help determine whether there are faults in the wiring or components that
provide information to the LH control unit. If all inputs and wiring are OK but operational problems still exist, the control unit
itself may be faulty.
Generally, a complete absence of voltage or continuity
means there is a wiring or connector problem. See 371 Wiring Diagrams, Fuses and Relays for help in diagnosis. Test
results with different values than those specified do not necessarily mean that a component is faulty. Check for loose connections or connections that are inadequate due to corrosion
or contamination. If the results are still incorrect, test the component itself.
8
7
6
5
4
3
2
1
DDDDDDDDDDDCID
DDDODDDDDDOJ
0
25 24 23 22 21 20 19 18 17 16 15 14
LH 2.4, LH 2.4.2
18 17 16 15 14 13 12 11 10 9
8
7
6
5
4
3
2
1
DDDDDDODODDDDOOCIDD 0
DODDDDDDDDODDDODD
35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19
Terminals viewed from back of connector
87677
Make these tests at the LH control unit connector using a
digital VOM. The control unit is mounted in the passenger
compartment, in the passenger-side footwell. See Fig. 8 given
Fig. 26. Terminal identification for LH fuel injection control unit connectors. Take care not to damage connector terminals with
test probes.
ELECTRICAL CHECKS AND COMPONENT TESTING
Page 166
240-20
Fuel Injection
CAUTION
NOTE
• On cars with LH 2.4 and LH 2.4.2 fuel injection, disconnecting the control unit connector will erase the control unit's
adaptive and diagnostic memory. When the engine is restarted it may operate erratically. The engine must be driven for at
least 30 minutes for the adaptive memory to be reset.
• Always connect or disconnect the control unit connector and
meter probes with the ignition off to avoid damage to electronic components.
• On models with LH 2.4 and LH 2.4.2, always wait at least 40
seconds after turning off the ignition before removing the control unit connector. If the connector is removed before this
time, residual power in the system relay may damage the control unit.
• The electrical tests below call for measuring voltage, current
or resistance using a digital volt-ohm meter (DVOM) or a multimeter. Using an analog meter may damage the control unit
or other solid state components
Table k. LH 2.2 Electrical Tests
Component or circuit
Test terminals (Test conditions at LH connector
unless otherwise noted)
Test conditions
I
I
-L-------
.--
Control unit power (switched), fuse 22
Test value
'I
18 and ground
Ignition on
Approximately 12 volts
(battery voltage)
-
Control unit grounds
Ignition on
18 and 5,18 and 11,
18 and 25
I
I
I
-------
--
System relay
Approximately 12 volts
(battery voltage)
I
I
-
-
~
I
----._-----
-
----------~---._.
System relay closes, power
to pin 9, power to pin 2 of air
mass meter
Jumper terminals 5 and 21
---+-
Fuel pump relay
(see 234 Fuel Pump and Fuel Tank)
Fuel pump runs, power to
oxygen sensor preheater
(blue/red wire), power to
fuel injectors (blue/red wire)
Jumper tenninals 5 and 17,
and 21 and 25
I
I
i
I
I
Ignition pulse signal
~ 1 and 25
Coolant temperature sensor
/---
-
-
i
~engine
I
2 and 25
I
-I ~hrottle
-
.-
3 and ground
Throttle position sensor
Continuity
closed
Throttle wide open
I
No continuity
Continuity
--
--
Ignition on, transmission in
Drive
4 and 25
Automatic transmission switch
(see 444 Automatic Transmission
Controls)
Resistance according to
~able g shown earlier
Throttle 1/2 open
12 and ground
2-3 volts (VAC)
I
- -
Approximately 12 volts
(battery voltage)
-----
AIC valve
/---
Fuel injectors
~
I
I
I
1----------
Air conditioning ON signal
i
40±4 ohms
10 and 23
I
13 and socket 87 of fuel
pump relay
4 ohms
I
I
12 and 16
Jumper sockets 16 and TK
of AlC compressor relay
Continuity
20 and 25
Oxygen sensor connected
No continuity
Separate connector and
connect green wire to
ground
Continuity
Disconnect EZK control unit
connector, bridge terminals
7 and 8 of connector
Continuity
I
I
I
Oxygen sensor
I
- -
Signal to EZK ignition system (ex. turbo
models) (see 340 Ignition System)
3 and 24
ELECTRICAL CHECKS AND COMPONENT TESTING
--
Page 167
Fuel Injection
240-21
Table I. LH 2.4 and LH 2.4.2 Electrical Tests
Component or circuit
Test terminals (at disconnected LH connector unless otherwise noted)
Test conditions
I
Test value
I
- -~~~--~------+_~~--~~~~~~~ -----t-~~~----------- ---
Control unit power (switched), fuse 22
35 and ground
Ignition on
Approximately 12 volts
(battery voltage)
~~Control unit power(con-s-ta-n-t-)~~~~~~~4~a-n-d-g-~~u-n-d~~-~--~---~~~~~~-~~'~~~-~~~-~-~ro~mate~~2vo~-~--~
.
CO:~~'t~g~rOU_n_ds_~_~~ ~~~~~-----t-+-4Juamndp~e5r'4tear-mndln1a7IS
__
System relay
and
~I
~
-17 and 21
,
I
-
I
I
--.. - - - - - . - - - - - - - - - - - -
Fuel pump relay (see 234 Fuel Pump and
Fuel Tank), power from system relay,
__~g_x:_j~:~ :::s::i:::~~~:O=:;
f----C-oo-I-a-nt-t-e-m-p-e-ra-t-u~re-s-e-n-s-o--r--
Jumper terminals 5 and 20,
and 17 and 21
11
11
Ignition pulse signal (LH 2.4.2)
1-
- - -
------~--I
I
Relay closes, power to pin
9, power to pin 5 of air mass
meter, power to fuel
injectors (blue/red wire)
r ---------1
I
I
Fuel pump runs, power to
blue-red wire at oxygen
_·_:~:7~~~o_~_:_:_~_;o_r ~~
a~17---- ---~c;;;;;kengi~~
and 17-~~-- ------~- I"Crank engine
2 and ground
volts
I
I
----+~d17---------~ - I~~-----------------
Throttle position sensor (LH 2.4)
t:~[~~~~~~~~)2
(battery voltage)
. - 6.5-;~lts (VAC)- - - - - - - Resistance according to
Table 9 shown earlier
Th rottle closed
Continuity
Throttle 1/2 open
No continuity
Throttle wide open
Continuity
i
I
3 and ground
Throttle potentiomete-r-(-L-H~2-.4-.-2-)~~~~~l-2-a-n-dl-0~
~---
---1--
--~~-~
I'
-~--
---
---------------------
-
Automatic transmission switch. (see 444
Automatic Transmission Controls)
---~------
-----------~--~
-----+-----~----~-
I ~g~nition on, transmission in
30 and 17
Approximately 12 volts
(battery voltage)
Drive
----------- --- - - -
-~~---------------+-----~-----~~~~
AIC valve (LH 2.4)
33 and 17
LH control unit connector
connected, engine running,
probe terminals from rear of
connector
- ~-~-
f----~~~~~~-
-~-~
Approximately 8 volts at
idle. Voltage should drop as
load increases
----- - - ~ ~ ~ ~ ~ ~ ~ - - -
~-----~--~~~~-
LH control unit connector
connected, engine running,
probe terminals from rear of
connector
AIC valve (LH 2.4.2)
Approximately 7 volts at
idle. Voltage should drop as
load increases
~-~~- -----~~~--~~-
----~--~-~----
4 ohms
18 and socket 87 of system
relay
Fuel injectors
Resistance according to
Table i shown earlier
I
I
---'--~~-~~~
14 and ground
Air conditioning ON signal (LH 2.4)
I
I
-~
--~---~-----~~--
-----~-~~~~t--~----~--~~~~
LH control unit connector
connected, engine running,
probe terminals from rear of
connector
---~~
~--~~~~~--
-
~-------~~--- - ~ - - - - ~ -
---f--~~--~~~~-
EGR modulating valve (where applicable~
see 254 Exhaust Emission Control)
19 and 17
--
less than 0.1 volt with AlC
off and battery voltage with
AlC on.
--~~-+-~~~~----------~-
Oxygen sensor connected
24 and 17
Oxygen sensor
I
less than 0.1 volt with AlC
off and battery voltage with
AlC on.
--+~~~~~-----~---j-~~--~--~~~-~---
14 and ground11 and
ground
Air conditioning ON signal (LH 2.4)
LH control unit connector
connected, engine running,
probe terminals from rear of
connector
Separate connector and
connect green wi re to
I ground
No continuity
Continuity
j-----~-------- -----------------~-Ignition on
Approximately 12 volts
(battery voltage)
i
continued on next page
ELECTRICAL CHECKS AND COMPONENT TESTING
Page 168
240-22
Fuel Injection
Table I. LH 2.4 and LH 2.4.2 Electrical Tests (continued)
Component or circuit
Test terminals (at disconnected LH connector unless otherwise noted)
Test conditions
Test value
1---
EGR valve temperature sensor (where
applicable-see 254 Exhaust Emission
Control)
23 and 17
Run engine at operating
temperature. Tum off
engine and disconnect
control unit connector (after
waiting 45 seconds)
Resistance should measure
several megohms
Charcoal canister purge vaive(ELCD) (see
254 Exhaust Emission Control)
27 and 17
Ignition on
Approximately 12 volts
(battery voltage)
Vehicle speed sensor
34 and ground
Ignition on, raise front of car
and rotate front left wheel
slowly
Voltage altemates between
0.5 and 5.0 volts
Upshift light
Jumper26 and 17
I Ignition on
Light illuminates
Ignition on
Light illuminates
i
Check Engine light
Jumper22 and 17
COMPONENT REPLACEMENT
To remove LH control unit
1. Disconnect the negative (-) battery cable.
2. Remove the door sill plate from the passenger side of
the car. Peel up the lower front edge of the door weather stripping.
3. Remove the trim plate holding the carpet to the front
side panel and peel the carpet until the control unit and
relays are visible.
3. Drain approximately 4 quarts of coolant from the cooling system. This is so that coolant will not leak out
when the sensor is removed. See 261 Radiator and
Cooling System.
4. Disconnect the sensor wiring and remove the sensor
using a 3/4 in. deep-well socket.
5. Before installing the new sensor, check the mating surface on the intake manifold. Use a new copper sealing
washer.
Tightening torque
• Coolant temperature sensor
4. Unplug the control unit harness connector by releasing
the fastener and then pivoting the connector up and off
of the unit.
5. Remove the mounting screws holding the control unit
to the body.
20 Nm (15 ft-Ib)
Installation is the reverse of removal. Refit the pressure regulator and crankcase ventilation hose. Make sure the LH system grounds are properly replaced on the pressure regulator
mounting.
Installation is the reverse of removal.
To remove throttle position sensor
To remove coolant temperature sensor
1. Detach the crankcase ventilation hose from the valve
cover.
2. Unbolt the fuel pressure regulator and its mounting
bracket from the cylinder head and push it to one side.
NOTE
On some models, it may be necessary to remove the regulator
completely for access to the temperature sensor.
1. Unplug the harness connector from the sensor. See
Fig. 12 given earlier.
2. Remove the mounting screws holding the sensor to the
side of the throttle housing.
Installation is the reverse of removal. On LH 2.2 and LH 2.4,
the switch must be adjusted as described below under LH
Fuel Injection Adjustments.
To remove air mass meter
1. Loosen the large hose clamp securing the rubber duct
to the air mass meter.
COMPONENT REPLACEMENT
Page 169
Fuel Injection
2. Disconnect the harness connector from the meter.
3. Release the two spring clip fasteners 'from the air
cleaner housing cover. See Fig. 27. Remove the air
240-23
WARNING
Wrap a clean shop towel around the banjo bolts before loosening them.
mass meter from the duct and cover.
CAUTION
To prevent damaging the fuel rail assembly, use an open-end
wrench on the flats on the rail to hold it steady while loosening
the fuel lines.
Fig. 27. Air mass meter and spring clip,
Installation is the reverse of removal. Where applicable,
make sure the ridge in the air mass meter and the recess in
the air cleaner cover are aligned before fastening the spring
clips.
To remove fuel injectors
WARNING
Fuel will be expelled when fuel lines are disconnected. Do not
smoke or work near heaters or other fire hazards. Keep a fire
extinguisher handy.
CAUTION
Absolute cleanliness is essential when working with fuel circuit components. Even a minute particle of dirt can cause
trouble if it reaches an injector. Thoroughly clean the unions
before disconnecting any fuel lines. Use clean tools.
Fig. 28. Fuel rail assembly and fuel lines (arrows).
4. Remove the bolts that hold the fuel rail to the intake
manifold and pull the fuel rail away complete with injectors.
5. To remove the injectors from the fuel rail, pry off the retaining clips, then twist the injectors slightly and pull
them off.
When installing the injectors, 'fit new O-rings to the injectors.
For ease of installation, lightly lubricate the O-rings with petroleum jelly. Install the injectors to the fuel rail but do not install
the retaining clips. Position the fuel rail and injectors on the intake manifold. Make sure that injectors and the fuel rail are fully seated and then install the retaining clips and mounting
bolts. Reconnect the fuel hoses to the fuel rail. Reconnect the
crankcase ventilation hose.
To remove fuel pressure regulator
1. Detach the crankcase ventilation hose from the valve
cover.
2. Unplug the wiring harness connectors from the injectors. Free the wiring harness from the fuel rail by undoing the clips. Carefully pull the harness to the side.
WARNING
Fuel under pressure will be expelled when fuel lines are disconnected. Do not smoke or work near heaters or other fire
hazards. Keep a fire extinguisher handy.
3. Disconnect the fuel inlet and outlet hoses on the fuel
rail by removing the banjo bolts. See Fig. 28.
1. Disconnect the vacuum hose from the regulator.
COMPONENT REPLACEMENT
Page 170
240-24
Fuel Injection
2. Disconnect from the regulator the fuel hose coming
from the fuel rail.
3. Remove the fuel pressure regulator mounting bolts and
lift out the regulator and its bracket. Disconnect the fuel
return hose from the regulator. Remove the regulator
from the bracket.
Installation is the reverse of removal. Remember to reconnect the ground wires to the fuel pressure regulator mounting
bolt.
To remove AIC valve
Base idle speed is set by reading the control unit signal to
the valve. This signal is known as the duty cycle. It is the ratio
of on-time to off-time of voltage and is expressed as a percentage. It is measured using a duty cycle or dwell meter.
NOTE
• Rememberthat 100% on a duty cycle meter corresponds to
90° on a dwell meter.
• The test meter must be a quality digital dwell meter, with an
accuracy of at least 0.5%. Using an inexpensive analog meter
that has an error of 2° would result in a selling 25% out of calibration.
1. Disconnect the harness connector from the AIC valve.
2. Loosen the valve's hose clamps and disconnect the
hoses from the valve. See Fig. 29.
To adjust AIC valve and basic idle speed
(LH 2.2)
NOTE
For the most accu rate adjustment, the engine should be at operating temperature, the ignition timing and idle mixture
should be checked and adjusted if necessary.
1. Back off the dashpot so that the plunger no longer contacts the throttle lever. See Fig. 30, Check that there is
slack in the accelerator cable. If necessary, loosen the
cable.
Fig. 29. AIC valve hose clamp being loosened,
3. Remove the valve bracket mounting bolt and remove
the valve from the bracket.
Installation is reverse of removal. On models with LH 2.2,
adjust the base setting of the valve as described below.
LH FUEL INJECTION ADJUSTMENTS
Except for the adjustment of the throttle position sensor, all
of the adjustment described below are for cars with LH 2,2
only, Cars with LH 2.4 and LH 2.4.2 are fully adaptive and do
not require any adjustments.
Setting the base idle speed ensures that the AIC idle control
valve is operating in about the middl,e of its range under normal conditions. Base idle speed is set at the factory and does
not normally need to be checked or adjusted, unless repairs
are made to the throttle valve or housing.
LH FUEL INJECTION ADJUSTMENTS
Fig. 30. Dashpot plunger should be backed off throttle lever (arrow),
2. Loosen the screws for the throttle position sensor so
that it doesn't affect the throttle valve. Disconnect the
sensor harness connector and connect a jumper wire
as shown in Fig. 31. This will simUlate a closed-throttle
signal.