Page 141
234-10
Fuel Pump and Fuel Tank
l
1985- early 1988
(up to VIN: J3001527 and J7004073)
NOTE
• Proper pump height and pump orientation in the tank is very
important. Scribe a mark 42 mm (121/32 or 1.65 in.) from the
top of the pump to accurately position the collar to the pump
during assembly.
• See 1 LUBRICATION AND MAINTENANCE for infonnation
on VIN numbers and their locations.
• The supply pump on some early models may be equipped
with a "bow-tie" style strainer. For better fuel pick-up and delivery, a modified strainer should be installed. See Fig. 15. The
new strainer is Saab Part No. 93 86 491.
4
---"fC---Supply pump
87291-52/1320
L
Fig. 15. Where installed, always replace bow-tie strainer (3) with modified strainer shown. Replace supports (1 and 2), clamp (4).
and O-ring (5) when using new strainer. Screw (6) must be reinstalled for proper pressurization of reservoir.
----=8=..:-7.::.:29:.::2_------.J
Fig. 16. 1985 to early 1988 fuel pump orientation relative to car,
1988 and later
(from VIN: J3001528 and J7004074)
8. Install the pump into the tank, making sure to reconnect
the supply pump connector and the fuel return line before fully installing the pump. Orient the pump as shown
in Fig. 16 or Fig. 17. Tighten the mounting collar clamp.
Supply pump
9. Using new sealing washers, reinstall the fuel line and
banjo bolt/dome nut. Reconnect the wiring.
NOTE
The direction of pump rotation is detennined by the polarity of
the wiring, so + and - signs are cast in the pump housing to
ensure proper wiring connection.
87293
Fig. 17. Early 1988 and later fuel pump orientation relative to fuel tank,
FUEL PUMP
Page 142
Fuel Pump and Fuel Tank
Replacing Rotor-type Pump
When removing and installing the rotor-type fuel pump, always replace the a-rings that seal the fuel lines and the pump
to the tank. This is especially important on 1990 and later
models because the a-rings are designed to swell when exposed to fuel vapor. These a-rings cannot be reinstalled unless they are completely dry.
234-11
WARNING
Fuel will be expelled under pressure. Wrap clean rags around
the fuel line fittings before removing them from the pump.
There were two styles of rotor-type pumps installed. The
early version had the supply check valve installed in the pump
assembly. The later pump (identified by the internal T-fitting in
the pump's supply line) had the supply check valve fitted in the
supply line fitting. If the early pump is replaced, a new check
valve must be inserted into the end of the supply line using
special tools, as the early-style pump is no longer available.
See Replacing Fuel Pump Check Valve below for replacement procedures.
To replace rotor-type pump assembly
1. Disconnect the battery negative (-) cable and coverthe
terminal pole on the battery.
Fig. 19. Fuel lines being removed.
NOTE
On cars with LH 2.4 fuel injection, disconnecting the battery cable will erase the control unit's adaptive memory. When the engine is restarted it may operate erratically for up to 30 minutes.
5. Loosen the large threaded retaining collar while holding the pump stationary.
CAUTION
2. Working in the luggage compartment, remove the access panel from above the pump.
3. Remove the clamp that secures the fuel lines and wiring. See Fig. 18. Disconnect the wiring from the pump.
The pump must not tum when loosening the retaining collar or
the ejector assembly could be damaged. A special tool is available to hold the pump stationary as the collar is loosened. See
Fig. 20.
6. Lift the pump assembly up to allow excess fuel to drain,
then tilt it slightly to remove it from the tank. Place it in
a receptacle to catch any remaining fuel.
NOTE
Carefully inspect the fuel delivery line. If the hose is distorted
or ballooned, it should be replaced. This hose is available as
a replacement part through and authorized Saab dealer. Be
sure to check the fuel system pressure if the hose is distorted.
Excessive fuel pressure due to a blocked check valve will
cause the new hose to balloon.
Fig. 18. Fuel line and pump wiring hold-down clamp.
7. Carefully insert the new pump assembly (ejector pump
side first) into the tank so that the fuel line fittings on the
pump are parallel with the length of the car and that the
matching mark on the pump is aligned with the mark on
the tank. See Fig. 21.
4. Using a round-jawed pliers, disconnect the fuel lines by
pulling them straight up. See Fig. 19. Tie the fuel lines
back.
FUEL PUMP
Page 143
Fuel Pump and Fuel Tank
Fig. 23. Threaded collar being tightened using Saab special tool
no. 83 94 462 on 1990 and later models.
NOTE
During 1990 production, the supply line check valve was
moved from the supply-line socket in the pump to the end of
the supply line itself. Make sure you identify each fuel line correctly before connecting it.
234-13
Fig. 25. Reservoir and filter unit being separated from pump top
section.
4. Fit a new O-ring to the ejector pump and reinstall it into
the reservoir, turning it 90° counter-clockwise to lock it
to the dog on the reservoir.
NOTE
Check that the ejector pump is clean. If necessary blow
through using compressed air to remove any foreign material.
To replace fuel pump screen
(models with rotor-type pump only)
1. Carefully ease back the lugs that secure the ejector
pump, turn the ejector 90° (1/4 turn) clockwise and remove it from the reservoir. See Fig. 24.
Replacing Fuel Pump Check Valve
A one-way check valve is used at the fuel pump supply line
to hold fuel pressure in the system after the pump shuts off. A
faulty valve can cause longer engine cranking on restart because of the loss of fuel system rest pressure. The check
valve is tested as part of a fuel system pressure test as described 240 Fuel Injection
WARNING
• Fuel under pressure will be expelled. Wipe up any spilled
fuel immediately. Wrap fuel lines with a clean rag before removing them. Do not smoke or create sparks. Have an approved fire extinguisher handy.
• Always remove the battery negative (-) cable before doing
any work on any fuel system component.
87402-S2/1381
Fig. 24. Ejector pump retaining lugs being eased back. Turn ejector
1/4 turn and remove from reservoir assembly.
2. Separate the reservoir and filter unit from the top section. See Fig. 25.
3. Install the new reservoir and filter assembly to the
pump upper part using a new O-ring.
To replace the check valve on models with roller-type
pump, remove the banjo fitting while holding the pump steady.
Then carefully remove the check valve from the pump. Install
the new check valve and the banjo fitting, using new sealing
washers. See Fig. 26.
CAUTION
Do not grip the check valve too tightly, as it may become damaged.
FUEL PUMP
Page 144
234-14
Fuel Pump and Fuel Tank
..
Fig. 26. Fuel pump check valve shown removed from roller-type
fuel pump.
On models with the rotor-type pump, two types of check
valves were used on the cars covered by this manual. On
1989 models, the return line check valve was part of the fuel
pump. On 1990 and later models, the check valve was integrated into the supply line fitting (elbow). If a 1989 pump is being replaced with the newer superseded pump or if the new
style checkvalve is faulty, installation of a new check valve will
require the use of a special tool.
To install the check valve in the supply line, first cut the old
fitting from the end of the line as close as possible to the fitting.
Using the special tool (Saab tool no. 83 94 546) and a channel-lock pliers, carefully press the new check valve fitting into
the fuel supply line. See Fig. 27. Use new a-rings when reconnecting the fuel supply line to the pump.
NOTE
Do not cut more than 12-14 mm (1/2 in.) of the supply line
when removing the fitting/check valve. If more than this is removed, a new fuel-pump-to-fuel-filter fuel line will have to be
installed.
FUEL TANK AND LINES
Fuel Tank
The fuel tank is held in place with two straps. Removal and
installation is fairly straightforward as long as the rear of the
car can be raised and supported securely. The following information is a general guide to the necessary steps for tank removal and Installation.
Fig. 27. New supply line check valve (2) being installed with Saab special tool (1). Always use new O-rings (3).
WARNING
Fuel will be expelled when the fuel lines are disconnected. Do
not smoke or create sparks. Have an approved fire extinguisher handy.
To remove and install fuel tank
1. Drain the fuel tank using the fuel pump. Run a hose
from the pump outlet on the tank into a suitable container. See Fig. 28. Then run the fuel pump without running
the engine as described earlier under Fuel Pump
Troubleshooting.
NOTE
The fuel tank is not equipped with a drain plug.
2. Disconnect the battery negative (-) cable.
NOTE
On cars with LH 2.4 fuel injection, disconnecting the battery
cable will erase the control unit's adaptive memory. The engine must be driven for about 30 minutes for the adaptive
memory to be reset.
3. Working from the luggage compartment, remove the
floor covers and disconnect the electrical leads from
the pump and fuel gauge sender.
4. Raise the rear of the car and support it securely.
FUEL TANK AND LINES
Page 145
Fuel Pump and Fuel Tank
234-15
NOTE
There are different fuel sender gaskets depending on the
sender installed. For the most correct replacement, bring the
old gasket to an authorized Saab dealer to match up with the
replacement gasket.
1. Disconnect the battery negative (-) cable. Cover the
battery terminal.
2. Remove the cover from above the sender in the luggage compartment. Disconnect the sender wiring.
from
Pump outlet
3. Remove the sender's threaded retaining ring.
NOTE
B7407-$7988
A Saab special tool (tool no. 83 93 365) is available to remove
and install the threaded retaining ring. See Fig. 29.
Fig. 28. Setup used to drain fuel tank. A vent hose should be used to
prevent emission of hydrocarbons.
5. Disconnect the filler pipe, breather lines, and fuel return
line from the tank. Undo the fuel line clips.
6. Remove the strap nuts and lower the tank.
NOTE
Before installing the tank, check that the rubber seal around
the fuel sender opening is positioned correctly and undamaged. Cover the tank openings with tape.
7. Raise the tank into position and support it with the
straps. Adjust the tank's lateral position, then tighten
the straps and remove the tape.
8. Reconnect the filler pipe, making sure the rubber grommet is in position.
9. Reconnect all fuel lines, clips, and electrical connections.
10. Lower the car and reconnect the battery negative (-)
cable.
To remove and install fuel gauge sender unit
WARNING
Fuel will be exposed. Do not smoke or create sparks. Have an
approved fire extinguisher handy.
B7408-S8208
Fig. 29. Fuel gauge sender retaining ring being removed using
socket wrench and Saab special tool no. 83 93 365. (Saab
Part No. 8393365).
4. Withdraw the sender and let it drain. Remove the old
seal and discard.
5. Fit a new sender seal, insert the sender into the tank,
and tighten the retaining ring. Reconnect the wiring and
fit the cover.
NOTE
New senders are shipped with a retaining wire at the bottom
to prevent float damage. Remove the wire before installing the
sender, or else the gauge will only read EMPTY.
To replace fuel tank rollover valve
1. Working in the luggage compartment, remove the trim
from the right-hand side.
FUEL TANK AND LINES
Page 146
234-16
Fuel Pump and Fuel Tank
2. Remove the rollover valve mounting screws and pull
the valve into the luggage compartment. See Fig. 30.
To replace banjo fitting on fuel line
WARNING
The procedure below requires the use of a soldering iron with
a knife tip. Completely remove the hose and its fitting from the
car. Move a safe distance away from the car and any open
fuel when making the repair.
1. Using a soldering iron, melt a notch into the into the end
of the line. See Fig. 31.
Fig. 30. Rollover valve in luggage compartment being removed.
3. Disconnect the hose from the valve and remove the
valve.
Installation is the reverse of removal. Make sure the long
outlet on the valve is facing up when installing.
Fuel Lines
The fuel lines that run from the fuel tank to the engine compartment are routed along the left-hand sill inside the car.
Fig. 31. Soldering iron being used to melt notch in fuel line.
2. Pull the fitting out of the fuel line. Cut the fuel line back
just enough to remove the melted notch made earlier.
3. Using a section of thick rubber hose, slice it open and
place it over the fuel line. Place the fuel line in a vice.
Allow the end of the line to overhang the vise jaws
slightly. See Fig. 32.
To replace fuel lines inside car
1. Remove the left-hand sill scuff plate and roll the carpet
back.
2. Peel back the tape holding the fuel lines to the body.
NOTE
As a better alternative to the split rubber hose, use Saab special tool no. 83 94 546 and a channel-lock pliers to install the
fitting to the fuel line. See Fig. 27 shown earlier.
3. Carefully remove the insulation felt from the bulkhead.
4. Disconnect the fuel return and supply lines in the engine compartment and pull the lines through the bulkhead grommets and into the passenger compartment.
5. Release the lines from the retaining clips at the fuel
tank and remove the lines from the car.
Installation is the reverse of removal. Clean the fuel lines
using low pressure compressed air. Tape the open ends before reinstalling them. Always replace fuel fitting sealing
washers and any crimp-type hose clamps.
Fig. 32. Fuel line (protected with rubber hose) installed in vice.
4. Tap the fitting into the fuel line until it is fully seated.
FUEL TANK AND LINES
Page 147
Fuellnjection
240-1
240 Fuel Injection
General
Principle of Operation
Safety Precautions
Fault Diagnosis
Basics Requirements for LH Fuel Injection
On-board Diagnostics
(LH 2.4 and LH 2.4.2 only)
To display LH fault codes
To erase fault code memory
To test components and signals
Fuel Pressure Tests
Relieving Fuel Pressure and Connecting
Fuel Pressure Gauge
Fuel Pressure Regulator
Checking System Line Pressure
Checking Residual Pressure
Checking Fuel Pump Delivery Pressure
Electrical Checks and Component
Testing
System Relay
To test system relay
Coolant Temperature Sensor
Throttle Position Sensor
Air Mass Meter
To test air mass meter
Fuel Injectors
To test injectors
Oxygen Sensor
To test oxygen sensor
Automatic Idle Control (AIC) System
To test AIC system
LH Control Unit
,
240-1
240-2
240-3
240-4
240-4
240-5
240-5
240-7
240-7
240-8
240-8
240-9
240-9
240-10
240-10
Component Replacement
To remove LH control unit
To remove coolant temperature sensor. . ..
To remove throttle position sensor . . . . . ..
To remove air mass meter. . . . . . . . . . . . ..
To remove fuel injectors
To remove fuel pressure regulator. . . . . . ..
To remove AIC valve
LH Fuel Injection Adjustments
To adjust AIC valve and basic idle speed
(LH 2.2)
To adjust throttle position sensor
(LH 2.2 and LH 2.4)
To check basic setting of
fuel injection system (LH 2.2)
To adjust dashpot (LH 2.2)
240-22
240-22
240-22
240-22
240-22
240-23
240-23
240-24
240-24
240-24
240-26
240-26
240-27
TABLES
240-10
240-11
240-11
240-12
240-12
240-13
240-14
240-14
240-15
240-16
240-16
240-17
240-18
240-19
GENERAL
All Saab 16-valve models feature Bosch LH Fuel Injection
as standard equipment. This system is also know as Hot-wire
fuel injection, owing to the operation of the air mass meter,
which uses a heated wire to help measure the incoming air.
Fuel injection component troubleshooting and repair are
covered in detail within this repair group. Special equipment
may be necessary for some of the procedures included here.
If you do not have the equipment or the experience required to
accurately do the job, we suggest leaving those tests or repairs to an authorized Saab dealer. The Saab dealer is
a. LH Fuel Injection Variants
240-3
b. Fuel Injection On-board Diagnostic Fault Codes
(LH 2.4, LH 2.4.2 only)
240-6
c. Fuel Injection Component Test
(LH 2.4, LH 2.4.2 only)
240-8
d. System Pressure - Fuel Pump Running,
Engine Off
240-9
e. System Pressure - Engine Idling
240-10
f. Residual Pressure
240-10
g. Coolant Temperature Sensor Resistance
240-12
h. Throttle Position Sensor Tests-LH 2.2
and LH 2.4
240-13
i. Throttle Position Sensor Tests-LH 2.4.2
240-13
j. AIC Valve Resistance
240-18
k. LH 2.2 Electrical Tests
240-20
I. LH 2.4 and LH 2.4.2 Electrical Tests
240-21
m.ldle Specification
240-26
equipped with special diagnostic test equipment; the ISAT (Intelligent Saab Tester) and the LH Tester. Both of these electronic tools are capable of quickly pinpointing hard-to-find LH
fuel injection problems.
NOTE
• Fuel supply-the system that pressurizes the fuel and delivers it to the injection system-is covered in 234 Fuel Pump
and Fuel Tank.
• Exhaust emission systems, such as Evaporative Loss Control (ELCD), and Exhaust Gas Recirculation (EGR) are covered separately in 254 Exhaust Emission Control.
GENERAL
Page 148
240-2
Fuel Injection
tered to the engine is determined solely by how long the
injectors are open.
Principle of Operation
Bosch LH fuel injection is completely electronic in operation. Air flow is measured electronically, and a proportional
amount of fuel is metered by electrically opening and closing
the fuel injectors.
There are three versions of LH fuel injection on 16-valve
models. Each has the same basic components and operating
principles. The differences among the three are mainly in refinements of certain operations and additional functions, introduced on newer models. See Table a.
In LH fuel injection, many sensors supply information about
engine operating conditions to a central electronic control unit
(ECU). The control unit then calculates the amount of fuel
needed for the correct air-fuel ratio and opens the fuel injectors, once for each engine revolution. The amount of fuel me
Air Intake. All air entering the engine passes through a
pleated paper air filter in the air cleaner. Air flow is controlled
by the throttle valve in the throttle housing. Along with the
throttle valve, the housing contains idle air passages, connec
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5
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12
T.
I:
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i18Q_~20
87412-8211038
1. Fuel tank
2. Fuel pump
3. Supply pump (Bosch pump only)
4. Fuel filter
5 Fuel rail
6. Fuel pressure regulator
7. LH control unit
~Ignition distributor
Fig. 1. Schematic view of LH fuel injection.
GENERAL
9. Ignition coil
10. Coolant temperature sensor
11. Fuel injector
12. Vacuum line
13. Intake manifold
14. Throttle position sensor
15 AIC (Automatic Idle Control) valve
16. Air mass meter
17. Oxygen sensor
18. Over-pressure switch
(1985-1988 turbo only)
19. System relay
20. Fuel pump relay
21. Battery
22. Ignition switch
-I
Page 149
Fuel Injection
240-3
Table a. LH Fuel Injection Variants
System
LH 2.2
I
YearlModel
1985-1988 Turbo
1986-1987 Non-turbo
LH 2.4
Identifi cation
1989-1992 Turbo
Three-wire AIC idle valve, metal air mass meter with a sealed mixture adjustment
screw, and a throttle dash pot
I
Two-wire AIC idle valve, plastic air mass meter without a mixture adjustment screw
1988-1990 Non-turbo
LH 2.4.2
1991 and later Non-turbo
Three-wire AIC idle valve, similar plastic air mass meter without a mixture adjustment
screw, and a throttle potentiometer.
tions for the Adaptive Idle Control (AIC) valve, and vacuum
connections. The housing is connected to the hot-wire air
mass meter by flexible rubber ducts. Air entering the engine is
measured by the air mass meter. The meter has no moving
parts. Instead, the meter measures air flow electronically and
generates a voltage signal. This signal is then used by the
control unit to determine how much fuel to inject.
Fuel Metering. The control unit meters fuel by changing the
opening time (pulse time) of the fuel injectors. To ensure that
injector pulse time is the only factor that determines fuel metering, fuel pressure is precisely controlled by a fuel pressure
regulator. The injectors are mounted to a common fuel supply
called the fuel rail. The control unit monitors engine speed (ignition pulse) to determine the rate of injector openings. Other
signals to the control unit help determine injector pulse time
for different operating conditions. A temperature sensor signals engine temperature for cold-start and warm-up enrichment. A throttle position sensor signals throttle position for
full-throttle and idle. An oxygen sensor signals information
about combustion efficiency for control of the air-fuel mixture.
Automatic Idle Control (AIC). Idle speed is electronically
controlled. The LH control unit controls an idle valve that allows air to bypass the closed throttle valve. This bypass control is known as the AIC system. The control unit makes
continual changes to the valve opening to adjust idle speed
based on engine operating conditions. The bypass air passage is upstream of the air mass meter, so mixture is not affected by changing the idle speed.
LH 2.4 Fuel Injection. Both the AIC and mixture control
systems are adaptive on this system. That means that each
system compensates automatically for changes in the engine
due to age or small problems. As a result, idle speed and mixture do not need to be adjusted. A deceleration fuel shut-off
function in the LH 2.4 control unit replaces the deceleration
dashpot used on LH 2.2. An integrated Evaporative Loss Control Device (ELCD) system is used on LH 2.4. Operation of the
ELCD valve is controlled by the LH control unit. Another main
feature of the LH 2.4 system is that it has on-board diagnostics. See On-board Diagnostics for more information.
LH 2.4.2 Fuel Injection This fuel injection system is used
only on 900 models with the 2.1 liter engine. LH 2.4.2 has all of
the features of the earlier LH 2.4 system, plus additional refinements. The system uses a new AIC valve. A throttle potentiometer replaces the throttle switch, and the control unit has
been reprogrammed to modify the control of many other functions, including additional diagnostic codes.
NOTE
Unless otherwise noted, all procedures and specifications in
this chapter apply to all LH fuel injection variants. Where distinction is important, the systems will be referred to by their alpha-numeric codes-LH 2.2, LH 2.4, LH 2.4.2.
Safety Precautions
The following warnings and caution should be adhered to
whenever doing work on the fuel injection system.
WARNING
• Fuel will be discharged during many fuel system test procedures. Do not smoke or work near heaters or other fire hazards. Have a fire extinguisher handy. Work only in a wellventilated area.
• Wear suitable hand protection, as prolonged contact with
fuel can cause illnesses and skin disorders.
CAUTION
• Connect and disconnect wires and test equipment only with
the ignition off.
• Before making any electrical tests that require the engine to
be cranked using the starter, disable the ignition system as
described in 340 Ignition System
• 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.
• Cleanliness is essential when working with parts of the fuel
system open. Thoroughly clean fuel line connections and surrounding areas before loosening. Avoid the use of compressed air, and avoid moving the car. Only install clean parts.
GENERAL
Page 150
240-4
Fuel Injection
CAUTION
Fuel system cleaners and other chemical additives other than
those specifically recommended by Saab may seriously damage the catalytic converter, the oxygen sensor and the plastic
gas tank.
shooting information can found in 200 Engine-General.
This information is organized to help isolate problems and
suggest more specific troubleshooting steps by taking all of
the interrelated systems into consideration.
Fig. 2 shows an overall view of the engine compartment to
help you identify component locations for testing and replacement.
FAULT DIAGNOSIS
Basics Requirements for LH Fuel Injection
The management of engine functions is controlled by a
number of systems-ignition, fuel injection, and emission
control. Because these functions are interrelated, it is difficult
if not impossible to isolate general driveability problems by examining components of the fuel injection system alone. For
this reason, engine management and driveability trouble
The following list contains basic checks that should be
made when experiencing fuel injection problems. Again, if in
doubt of whether the fault is caused by the fuel system or
l
@
1. Air cleaner
2. Air mass meter
3. Fuel injectors
4. Fuel pressure regulator
5. Fuel rail
6. Throttle housing
7. Ale idle valve
8. Fuse/relay panel
9. Intake manifold
87687
. _ - _..- -
Fig. 2. Typical view of engine compartment from front of car.
FAULT DIAGNOSIS
-