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Engine-General
200-9
B 7091
Fig. 10. Oxygen sensor reacts to oxygen content in exhaust gas to
constantly monitor air-fuel mixture,
I
Fig. 11. Common places to check for intake air leaks (shaded areas),
Intake air leaks can cause rough running, especially at idle.
As the sensor ages, it loses its ability to react quickly to
changing conditions. It may eventually cease to produce any
signal at all. When this happens, idle speed may fluctuate and
fuel consumption may increase. The oxygen sensor should
be replaced at the specified mileage interval as described in
1 LUBRICATION AND MAINTENANCE.
Air Flow Measurement and Vacuum Leaks
The Bosch LH fuel injection system uses an air mass meter
to precisely measure incoming air. The air mass meter sends
an electrical signal to the LH control unit proportional to the
amount of air passing through the meter. This is the main input
used to determine the amount of fuel delivered to the engine.
Because proper fuel metering depends on accurately metering the intake air, any unmeasured air entering the system
will cause a lean fuel mixture and poor running. To see how air
leaks can affect engine running, remove the oil filler cap while
the engine is running.
There are many possible places for unmeasured airto enter
the engine. Carefully inspect for cracks or looseness all hoses, fittings, duct work, and seals and gaskets. See Fig. 11. For
a thorough inspection, it may be necessary to remove hoses
and ducts that cannot be completely checked in their installed
positions. Check that the throttle mounting nuts are tight and
that the throttle plate is closed.
Use a vacuum gauge connected downstream of the throttle
plate to check engine vacuum. Start the engine and let it idle.
If the system is operating correctly, engine vacuum should be
within the range listed below.
Engine Vacuum
• at idle (850±50 rpm) .. 12 to 23 in. Hg (-.4 to -.8 bar)
In addition to air leaks, an air restriction can cause driveability problems. Remove the air filter and check that it is clean.
Hold the filter up to a strong light source. If the light cannot be
seen through the filter it should be replaced. Remove the air
bellows from the throttle housing and check for residue
around the throttle plate. Large amounts of residue on the
throttle plate can cause an erratic idle. Clean the throttle housing with a carburetor cleaner and reinstall the bellows. Check
the AIC idle setting as described in 240 Fuel Injection.
NOTE
• On turbo models, be sure to check the hoses and plastic
hose clamps on the turbo bypass valve. The valve is located
on the compressor side of the turbocharger. See Fig. 12. If the
car exhibits minor driveability problems and no other vacuum
leaks can be found, check the operation of the bypass valve
as described in 291 Turbocharger. The valve may be faulty
and leaking internally.
• Some early 1985 models may not have a turbo bypass
valve.
Electrical System
All the cars covered by this manual use fuel injection and ignition systems that rely on precise electrical signals for proper
operation. If any of these signals are distorted, incorrect, or
missing, the car can develop major driveability problems.
Battery Voltage
One of the most fundamental requirements in troubleshooting engine performance problems is to make sure the battery
is fully charged and in good condition. Many of the sophisticat-
ORIVEABILITY TROUBLESHOOTING
Page 72
200-10
Engine-General
NOTE
In most cases, faulty electronic control units are not the cause
of driveability problems. These units are extremely durable
and reliable. Actual failures are very rare. Driveability problems are more often caused by missing or incorrect signals to
the control unit, or other faulty components.
The electrical system is subject to corrosion, vibration,
roadway elements and general wear. Because of this, the integrity and freedom from corrosion in the connections, wires,
and switches, including all ground connections, is one of the
most important conditions for trouble-free operation of the fuel
injection and ignition systems.
Fig. 12. Leaking turbo bypass valve (arrow) can be the source of minor driveability problems.
ed electronics used on the cars covered by this manual require a specific operating voltage to function correctly.
Battery voltage can be measured across its terminals with
all cables attached. Do not eliminate the battery as a possible
source of trouble until a load test has been performed, especially if starting problems are encountered. See 300 Electrical-General for battery testing information.
NOTE
A digital voltmeter should be used to measure battery voltage.
A fully charged battery will measure 12.6 volts, or more, as
compared to a battery only 25% charged that measures 12.15
volts. Using an analog meter may result in inaccurate results.
For the battery to maintain its proper voltage level, the
charging system must be functioning correctly. If in doubt
about the condition of the charging system, have the system
checked. Most automotive repair shops can test the system
quickly and at a reasonable cost.
Wiring and Harness Connectors
The cars covered by this manual are equipped with electronic fuel injection and ignition systems that are controlled by
central electronic control units. Many of the circuits operate on
very low current and are sensitive to increased resistance due
to faulty or corroded wiring or connectors.
ORIVEABILITY TROUBLESHOOTING
Always make a thorough visual inspection of all wires and
connectors, switches and fuses. Loose or damaged connectors can cause intermittent problems, especially at the small
terminals in each control unit connector. In most cases, a visual inspection will detect anyfaults.lf aconnector shows novisible faults, but is still suspect, perform a voltage drop test at
the connector. Even a small amount of corrosion in a connector can cause a large voltage drop to the circuit's load. See
300 Electrical-General for more electrical troubleshooting
information.
Ground Connections
For any electrical circuit to work, it must make a complete
path, beginning atthe negative (-) battery terminal and ending
at the positive (+) terminal. The negative (-) battery cable runs
directly to the car's chassis. Therefore, connecting a wire to
the chassis or any metal part bolted to the chassis provides a
good ground source or path back to the negative (-) side of the
battery.
Poor ground connections are one of the major sources of
driveability problems. There are only a few main ground connections or points for the fuel injection and ignition systems. If
any of these ground points are faulty, the voltage to the circuit
will be reduced or even eliminated. Be sure to carefully check
the main ground(s) forthe LH system atthe engine lifting bracket on the intake manifold. Also check the ground for the fuel
pump at the center crossmernber in the luggage compartment.
When checking ground wires, ground points, or ground
straps, begin with a thorollgh visual inspection. Ground connections and wires can corrode, become loose, or break in areas that are not visible. To thoroughly check a circuit ground,
check the voltage drop between the connector and a good
ground source. Large voltage drops indicate too much resistance. The connection is corroded, dirty or otherwise dam-
Page 73
Engine-General
aged. Clean or repair the connection and retest. Also check
both battery terminals and all ground straps between the engine and the body for voltage drops.
NOTE
For voltage drop tests and other general electrical troubleshooting information, see 300 Electrical-General.
Fuel System
For the engine to start quickly when cold or hot, run correctly throughout all operating conditions, and accelerate smoothly without hesitation, the fuel system must deliver a precise
amount of fuel in relation to the amount of air that is drawn in
by the engine.
Fuel Supply
To start and run, the engine needs an adequate supply of
fuel. Fuel from the tank is supplied to the engine via an electric
fuel pump, a fuel filter, and the connecting fuel lines. If either
the filter or a fuel line is restricted, the engine may not run
properly. If the restriction is severe, or the main fuel pump is
faulty, the engine may not start at all. If fuel delivery problems
are suspected, check the fuel pump and pump relay as described in 234 Fuel Pump and Fuel Tank.
NOTE
On some turbo models, a faulty turbocharger over-pressure
switch can cause a no-start condition. The turbocharger overpressure switch is designed to tum off the fuel pump during
overboost conditions. Test this switch as described in 291 Turbocharger.
The fuel injection system has the main function of delivering
the correct amount of fuel for all engine operating conditions.
Basic fuel delivery is dependent on fuel pressure and the correctly functioning injectors. Fuel pressure is often overlooked
when diagnosing driveability problems.
200-11
The 'fuel pressure 'from the 'fuel pump is controlled by a pressure regulator. This regulator returns surplus fuel to the fuel
tank. The amount of fuel delivered to the engine is varied by
changing the amount of time the electric pulsed-type fuel injectors remain open. A change in fuel pressure results in a
change in the amount of fuel (or fuel mixture) delivered to the
engine. Fuel pressure and fuel pressure regulator tests are
described in 240 Fuel Injection.
NOTE
Fuel pressure tests require the use of a pressure gauge. If this
equipment is not available, fuel pressure tests can be performed by an authorized Saab dealer or other qualified shop.
Correctly operating fuel injectors playa major role in fuel
delivery. The injectors are switched on and off at the ground
side of the connector. Positive (+) battery voltage is always
present at the connector when the car is running. An injector
can become clogged, it can completely fail or lose power and
refuse to open, or it can short to ground and remain open
whenever the engine is running. Checking if an injector is fundamentally working can be accomplished easily; checking an
injector's spray pattern is more difficult. See 240 Fuel Injection for additional information.
NOTE
High or low fuel pressure or a faulty injector will result in an incorrect fuel mixture and overall poor driveability. A lean mixture (too little fuel) can cause the engine to run poorly when
cold or stumble upon acceleration. A rich mixture (too much
fuel) can dilute the engine oil, foul the spark plugs, and cause
a rough idle.
Table c lists some of the more common driveability symptoms, causes and corrective actions. The boldface type indicates the repair group where the applicable tests and repair
procedures can be found.
ORIVEABILITY TROUBLESHOOTING
Page 74
Engine-General
200-12
Table c. Engine Management-Driveability Troubleshooting
SYMPTOMS
a. Engine fails to start
b. Engine starts but stops immediately
c. Erratic idling
d. Poor response on acceleration
e. Engine erratic in all speed ranges
f. Excessive fuel consumption
g. Engine fails to rev up (no power)
h. CO content too low
i. CO content too high
a
a
b
CAUSES
CHECK/REMEDY
Fuel pump not running
Test fuel pump. 234
Ignition system faulty
Test ignition system components
340
a
b
System relay faulty
Test system relay. 240
a
b
Fuel pump relay faulty
Check fuel pump relay. 234
a
b
c
AIC idle valve faulty
Test AIC valve. 240
c
EGR valve sticking or faulty
Test and clean EGR valve. 254
Throttle position sensor faulty or out of
adjustment
Test throttle position sensor and adjust if
necessary. 240
Air mass meter faulty
Test air mass meter. 240
Induction (intake) system leaking
Checks for air leaks. Make a vacuum gauge
test. 200
i
Fuel pressure too low
Measure fuel pressure. 240
i
Fuel pressure too high
Measure fuel pressure. 240
Fuel pump output too low
Make fuel delivery test. 234
b
a
b
a
f
c
d
e
f
g
i
c
d
e
g
h
c
d
e
g
h
f
a
b
c
d
e
d
e
f
g
h
g
h
i
Coolant temperature sensor faulty
Test sensor resistance, replace if necessary.
240
c
d
c
e
f
e
f
f
i
g
Oxygen sensor faulty
Test oxygen sensor output signal. Replace
sensor if mileage interval exceeded. 254
Fuel injectors leaking
Check fuel injectors for leaks. Replace leaky
injectors. 240
Check throttle plate and adjust if necessary.
Binding throttle plate, or throttle plate
incorrectly adjusted
240
a
b
c
d
e
f
g
h
i
Electrical connection(s) loose, broken, or
corroded
Visually inspect electrical connectors and
correct any faults found. 300
a
b
c
d
e
f
g
h
i
Ground point(s) loose, broken, or corroded
Visually inspect ground points and correct any
faults found. 300
b
c
CO content too high
Test ai r mass meter. 240
b
c
d
CO content too low
Test air mass meter. 240
b
c
d
a
f
e
f
g
h
i
Input(s) signals to LH control unit missing
Make electrical tests at control unit connector.
240
g
a
b
c
d
e
f
g
h
i
ORIVEABILITY TROUBLESHOOTING
Turbocharger APC system faulty
Test APC system components. 291
LH control unit faulty
Test inputs to control unit. If all inputs are
correct, replace control unit. 240
Page 75
Engine Removal and Installation
201-1
201 Engine Removal and Installation
Removing and Installing Engine ..... 200-1
To remove engine
and transmission assembly
Separating Engine
from Transmission
200-1
To separate engine from transmission
(manual transmission)
To separate engine hom transmission
(automatic transmission)
200-9
200-10
200-9
REMOVING AND INSTALLING ENGINE
The engine is removed together with the transmission as a
complete assembly. The removal and installation procedure
described below applies specifically to 1988 turbocharged
models with manual transmission. Minor departures from the
procedures may be necessary depending on model year, engine and transmission.
NOTE
The Saab special tool is used to hold the suspension control
arm in its loaded position while the car is raised. This aids in
disconnecting the drive axle inner joint from the transmission
as the engine is pulled.
To remove engine and transmission assembly
1. Open the hood and disconnect the windshield washer
hoses. Remove the hood hinge mounting bolts and
carefully lift off the hood. See Fig. 1.
Fig. 2. Special tool (arrow) inserted between body and suspension
control arm to limit suspension travel.
3. Disconnect the battery leads and remove the battery.
4. Disconnect the exhaust pipe from the exhaust manifold. See 252 Exhaust System.
Fig. 1.
Hood hinge bolt being removed,
2. Using the steering wheel, turn the right-hand wheel to
its full right-lock position. Then insert Saab special tool
no. 83 93 209 between the upper control arm and the
body as shown in Fig. 2.
5. Loosen the right-hand wheel lug bolts.
6. Drain the power steering fluid reservoir. See 644 Power Steering.
7. Raise the car enough to work safely under it and support it securely on jackstands.
REMOVING AND INSTALLING ENGINE
Page 76
201-2
Engine Removal and Installation
WARNING
Never work under a lifted car unless it solidly supported on
stands designed for the purpose. Do not work under a car
supported solely by a jack.
8. Remove the nut 'from the shift selector rod taper pin
and tap the pin out of the rod. See Fig. 3. Disconnect
the rod 'from the shift linkage.
Fig. 4. Unscrew speedometer cable retaining collar (arrow) and pUll
cable from bearing housing.
Fig. 3. Manual shift selector rod taper pin retaining nut (arrow).
NOTE
For removal of the shift cable on models with automatic transmission see 444 Automatic Transmission Controls.
9. Thoroughly clean the area around the speedometer cable at the left-hand differential-bearing housing. Unscrew the speedometer cable from the housing. See
Fig. 4.
10. Remove the mounting bolts holding the front exhaust
pipe bracket to the transmission. See Fig. 5.
11. Remove the large clamps holding the inner drive axle
joint boots to the drive axle drivers. Pull the boots off
the drivers.
12. Remove the right-hand road wheel. Remove the two
through-bolts from the lower ball joint. Separate the ball
joint from the control arm and remove the inner drive
axle joint from its driver. See Fig. 6. Push the drive axle
assembly forward and rest it on the control arm.
REMOVING AND INSTALLING ENGINE
Fig. 5. Front exhaust pipe mounting bracket. Remove bracket
bolts (arrows) from transmission.
CAUTION
Cleanliness is essential when working on drive axle joints.
Even a small amount of sand or dirt will appreciably shorten
the service life of the joint. Cover or wrap the joint and inner
drivers on the transmission.
13. Disconnect the power steering pump pressure line
union on the exhaust side of the engine. See Fig. 7.
Page 77
Engine Removal and Installation
Fig. 6.
201-3
Hub assembly and drive axle being pUlled out to remove inner
joint from drive axle driver, Rest drive axle on control arm,
a. Heater core (label hoses
before removing)
b. Expansion tank
c. Thermostat housing
Fig. 8. Coolant hoses to be disconnected,
87203-211448
Fig. 7.
NOTE
Use a small screwdriver to remove the connector retaining
clips where necessary.
Power steering pump pressure line union being disconnected.
14. Drain the coolant from the radiator and block as as described in 261 Radiator and Cooling System. Disconnect the coolant hoses shown in Fig. 8.
16. On turbo models, disconnect the turbocharger discharge pipe.
17. Remove the air mass meter with its rubber socket connector.
15. Disconnect the wiring connectors and ground wires
shown in Fig. 9. Lift the wiring loom out of the engine
compartment and rest it on the Ale evaporator housing.
Position all other disconnected wires and connectors
so that they will not interfere with the engine's removal.
REMOVING AND INSTALLING ENGINE
Page 78
201-4
a.
b.
c.
d.
Engine Removal and Installation
AlC temperature sensor
Coolant temperature sensor
AlC compressor thermo-switch
Shift-up indicator vacuum switch
e.
f.
g.
h.
Air mass meter
Throttle-position sensor
AIC valve
Ground wires
i. Radiator cooling fan thermo-switch
j. Injectors
Fig. 9. Wiring connectors and ground wires to be removed.
18. Remove the air cleaner together with the intake air
pipe. See Fig. 10.
21. Remove and label the wires at the ignition coil. Remove
the coil from its bracket.
19. Remove the intercooler together with the air pipe. See
Fig. 11. Cover or cap the inlet to the turbocharger.
22. Remove the AlC radiator cooling fan. See 261 Radiator and Cooling System.
20. Remove the intercooler side baffle plate and top cover.
See Fig. 12.
23. Disconnect the lower radiator hose from the radiator.
REMOVING AND INSTALLING ENGINE
Page 79
Engine Removal and Installation
Fig. 10. Air cleaner assembly and intake air pipe being removed.
201-5
Fig. 12. Intercooler side baffle plate being removed.
Fig. 11. Intercooler and air pipe being removed,
Fig. 13. APe solenoid, Remove harness connector and hoses
(arrows), Label hoses before removal.
24. Disconnect the harness connector and hoses from the
turbocharger APC solenoid. See Fig. 13. Label the hoses before removing them.
25. Disconnect the accelerator cable from the throttle
housing and its bracket.
26. Disconnect the vacuum hoses for the brake booster
and the charcoal canister at the intake manifold and
throttle housing.
27. Disconnect the wiring connectors and wires shown in
Fig. 14. Cut any wiring ties and lift the wiring loom out
of the engine compartment and set aside. Position all
other disconnected wires and connectors so that they
will not interfere with the engine's removal.
NOTE
Use a small screwdriver to remove the connector retaining
clips where necessary.
REMOVING AND INSTALLING ENGINE
Page 80
201-6
Engine Removal and Installation
-
i
I
87210-54/1 523
a. Shift-up indicator switch
b. Knock sensor
c. Alternator
d. Oil pressure sensor
e. Starter motor
f. Throttle position sensor for AlC
g. Temperature gauge sender
h. Hall generator
Fig. 14. Wiring connectors and ground wires to be removed.
28. Remove the positive battery cable from it brackets on
the engine and on the starter motor. Set the cable on
the battery tray.
29. Disconnect the ground wire at the timing chain cover
and the transmission.
30. Unplug the oxygen sensor connector above the righthand wheel well. Unhook the wiring harness from the
fender and set it on the engine.
31. Disconnect the hydraulic line from the clutch slave cylinder. See Fig. 15.
REMOVING AND INSTALLING ENGINE
32. Disconnect the fuel supply line and return line from the
fuel rail and fuel pressure regulator.
33. Unbolt the AlC compressor (4 bolts) and carefully place
the compressor on the AlC evaporator housing without
disconnecting or loosening any refrigerant hoses.
WARNING
Loosening or disconnecting refrigerant hoses will allow the refrigerant to be discharged under high pressure, possibly causing personal injury. Recharging a discharged AlC system
requires special equipment and knowleqge.