Page 221
Ignition System
340-5
Table a. Ignition System Troubleshooting
1.
Symptom
Probable cause
No spark or weak
spark observed
during spark test
a. Wet or damp distributor cap and/or
spark plug wires
b. Faulty wires or connectors (primary
circuit).
c. Weak or faulty coil
c. Test and replace as needed
d. Defective spark plug wires
d. Test and replace as needed
I
I
e.
f.
Worn or fouled spark plugs
Faulty Hall sensor
g. Faulty ignition control unit or amplifier
Corrective action
a. Remove cap and wires. Dry and reinstall
b. Test and replace as needed
e. Replace spark plugs. See 1 LUBRICATION AND
MAINTENANCE
f. Test and replace as needed
g. Test and replace as needed
I
I
I
L
87394-S3/797
- - - - - - - - - - - - - - - -
Fig. 4.
Broken or missing
carbon tip
Rring order and proper orientation of high tension leads.
87438
I
~--------~
Visual Inspection
The spark plug wires, the distributor cap, and the distributor
rotor are subject to wear and electrical breakdown, which will
impair their ability to deliver a crisply timed and powerful
spark. Dirt and moisture on any of these components are also
potential causes of poor spark at the spark plugs.
To inspect the distributor cap and rotor, first unclip and remove the cap. Inspect the contacts inside the distributor cap
and at the tip of the rotor for carbon tracks, wear, or pitting.
See Fig. 5. Cracks or carbon tracks in the distributor cap may
cause shorts to ground. The cracks may be fine and difficult to
see. Check that the center black carbon brush inside the cap
springs back when compressed. If any faults are found, replace the cap and/or rotor.
To visually check the spark plug wires, gently bend them in
several places. This will expose cracks in the insulation which
may cause spark "leaks". Peel back the rubber boots and
check them for pliancy and the ability to seal out dirt and moisture. Wires that are cracked, oil-soaked or dry and brittle
should be replaced.
The coil should be closely examined for cracks, burns, carbon tracks, or any leaking fluid. The coil tower, center terminal
4, should be clean and dry. If necessary, remove the coil for
Fig. 5.
Distributor cap and rotor. Inspect cap and rotor at contact
points.
cleaning and closer examination. Check that the wiring at the
coil top is not contacting the metal coil housing. Loosen the
nuts and reposition the wires if necessary.
Inspect all primary wires and connections for any corrosion
or damage. Clean or repair any faults found. In these sensitive
electronic ignition systems, corroded or loose connections
may interfere with the ignition function.
ELECTRICAL TESTS AND
FAULT TRACING
The following electrical test should be done in the sequence
given. Review the information given earlier before making the
tests described here. On cars with EZK ignition, be sure to
check for any EZK fault codes as described earlier.
For the most accurate test results, check that the battery is
fully charged, there is fuel in the tank, and that engine and ambient temperature are between 32°F and 104°F (O°C and
40°C).
ELECTRICAL TESTS AND FAUL T TRACING
Page 222
340-6
Ignition System
3. Check for power to the ignition control unit. Disconnect the connector from the ignition control unit. See
Fig. 7. Connect a voltmeter to terminal 4 (+) and terminal 2 (-) of the control unit connector. See Fig. 8. Turn
the ignition on and check that the voltage is at least 10
volts (DC). Turn the ignition off and reconnect the connector. If voltage is as specified, proceed to the next
step. If voltage is not present, use the diagrams shown
in 371 Wiring Diagrams, Fuses and Relays to check
for wiring faults.
CAUTION
Do not unplug components or disconnect grounds when the
ignition key is on. Damage to electronic components could result.
To test basic Hall ignition system
(turbo models only)
1. Check the basic components subject to wear and
electrical breakdown. Test the condition of the spark
plug wires and the ignition rotor by testing the resistance of each component.
NOTE
It may be necessary to remove the control unit from its mountings to gain access to the connector.
Spark Plug Wire and Rotor Resistances
• Ignition rotor. . . . . . . . . . . . . . . . . . . .. 1,000 Ohms
• Coil high tension lead
(complete with end connectors) .. 500-1,500 Ohms
• Spark plug leads (complete with
end connectors)
2,000-4,000 Ohms
2. Check for power to the Hall sensor. Unplug the wiring connector from the side of the distributor. Connect
a voltmeter between the two outer terminals in the connector. See Fig. 6. Turn the ignition on. The voltmeter
should read at least 10 volts {VDC). Turn the ignition off
and reconnect the connector. If no faults are found, proceed to the next step. If voltage is not present, check
the wires between the distributor connector and the
control unit. Repair any wiring faults before proceeding.
Fig. 7. Ignition control unit in left front (driver's side) fender well.
O"al"
~ao ,~- I
10
olts
15
1
Greater than 10 volts
Ign~ion
15
ElectrOniC
Ignition
Electronic
Control
Unit
Control
Unit
54 3 2 1
87414
Fig. 6.
Voltmeter being used to check for voltage to Hall sensor.
87416
Fig. 8. Voltmeter being used to check for voltage to control unit.
ELECTRICAL TESTS AND FAUL T TRACING
Page 223
Ignition System
4. Check the Hall sensor output signal. Peel back the
rubber boot on the control unit connector. Connect a
voltmeter between terminal 6 and 3, working from rear
of the connector. See Fig. 9. Turn the ignition on and
slowly turn the engine over by hand. The voltage
should oscillate between 0.4 (DC)volts (or less) and 3.0
volts (or higher). If no faults are found, proceed to the
next step. If any faults are found, check the wires between the control unit and the Hall sensor. If no wiring
faults are found, the Hall sensor is faulty and should be
replaced.
CAUTION
Tum the engine over only in the direction of nonnal rotation.
Otherwise damage to the timing chain and its components
may result. To detennine nonnal rotation, put the car in gear
and rock the car forward, noting the rotation of the ignition rotor, the flywheel, or a belt-driven component. As an alternative, briefly operate the starter.
340-7
Ignition coil resistance*
• between terminal 1 and 15
• between terminal 1
and center tower
0.5 to 0.9 Ohms
7200 to 8200 Ohms
• measure with all wires disconnected from coil
Primary circuit
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NOTE
The engine can be tumed over using a wrench on the crankshaft pulley.
87413
~--------------
~ I=:J II
'~
~
- - - -
Fig. 10. Call circuits being tested using ohmmeter. Coil terminal numbers are found on coil.
Less than 0.4 volts
to 3.0 volts or higher.
15
7. Check the ignition control unit switching function
to the coil. Disconnect the Hall sensor connector from
Ignition
Electronic
Control
Unit
76543
I
.t-------. . .
87417
the distributor. Connect the voltmeter between coil terminals 15 and 1. See Fig. 11. Turn the ignition on. The
voltage should rise to about 5 volts (DC) and then drop
to 0 volts within 1 to 2 seconds. Reconnect the connector. If any faults are found, the control unit is faulty and
should be replaced. If no faults are found, the ignition
system is functioning correctly.
Fig. 9. Voltmeter being used to check Hall sensor operation.
NOTE
If on 1986 and 1987 models, all electrical checks are as spec
5. Check for power to the coil. Connect a voltmeter between terminal 15 (+) of the coil and ground. Turn the
ignition on and check that the voltage is at least 10 volts
(DC). Turn the ignition off. If voltage is as specified, proceed to the next step. If voltage is not present, use the
diagrams shown in 371 Wiring Diagrams, Fuses and
Relays to check for wiring faults.
ified but the car still does not start, check the ignition pulse
amplifier on the main fuse relay panel. See Fig. 12. This relaylike amplifier is designed to "amplify" the tachometer signal for
more reliable control of electronic components affected by the
ignition system (LH fuel injection, fuel pump control, etc.). To
check the amplifier, simply remove it from its socket. Then using a jumper wire, jumper the fuse/relay panel sockets corresponding to relay tenninals TO-I and TO-a. Try to start the
engine. If the engine now runs, replace the amplifier.
6. Check the coil primary and secondary circuit resistance. Remove all wires from the coil. Measure the coil
primary and secondary circuit resistance as shown below in Fig. 10. Reconnect the wires to the coil. If the coil
resistance is not as specified, the coil is faulty and
should be replaced. If no faults are found, proceed to
the next step.
ELECTRICAL TESTS AND FAUL T TRACING
Page 224
340-8
Ignition System
2. Test the knock sensor output signal. Remove the
harness connector from the EZK control unit. See Fig.
13. Using a digital voltmeter (set to VAC scale), connect it to terminal 12 and 13 of the control unit connector. Gently tap on the knock sensor mounting bolt. The
voltmeter should register a small voltage and the reading should vary depending on the intensity of the tap.
Ignition
NOTE
• The knock sensor is mounted to the engine block between
cylinders no. 2 and 3, below the intake manifold.
Electronic
Control
Unit
III
B74 19
Fig. 11. Voltmeter being used to check control unit sWitching function.
• Procedure step 1 checks both the knock sensor and the wiring to the control unit. If the knock sensor does not respond to
the tapping, remove the sensor and its connector. Then con·
nect the voltmeter directly to the sensor terminals and repeat
the above test. If the sensor now tests good, check the wiring
from the sensor connector to the ElK control unit. If the sensor does not respond, it is faulty and should be replaced.
Left
headlight
Ignition
amplifier
Fig. 12. Ignition pulse amplifier used on 1986 and 1987 models.
A faulty pulse amplifier will cause a no-start condition.
To test EZK ignition system
(non-turbo models only)
1. Check the basic components subject to wear and
electrical breakdown. Test the condition of the spark
plug wires and the ignition rotor by testing the resistance of each component.
Spark Plug Wire and Rotor Resistances
• Ignition rotor
1,000 ohms
• Coil high tension lead
(complete with end connectors) ... 500-1,500 ohms
• Spark plug leads (complete
with end connectors)
2,000-3,000 ohms
ELECTRICAL TESTS AND FAUL T TRACING
67421-S2l1159
Fig. 13. ElK control unit and amplifier locations in left (driver's) side
fender well. On 1988 and 1989 cars, amplifier is on side of ignition coil.
NOTE
On all cars except 1988 and 1989 models with ElK ignition, a
conventional coil with a separate amplifier is used. On 1988
and 1989 cars with ElK ignition, a special coil with integrated
amplifier is used. See Fig. 14. Testing procedures and replacement parts vary depending on coil style.
Page 225
Ignition System
340-9
NOTE
On fender-mounted amplifiers, the amplifier should be removed from its mountings to access the hamess connector.
5. Check for power to the coil. Connect a voltmeter between terminal 15 and ground on conventional coils or
between terminal 3 and ground on coils with amplifier.
With the ignition on, there should be battery voltage. If
no faults are found proceed to the next step. If voltage
is not present, use the wiring diagrams to check for wiring faults from the ignition switch.
6. Check the coil primary and secondary circuit resistance. With the ignition off, remove all wires from the
coil. Measure the resistance of the coil circuits as
shown in Fig. 16. If any faults are found the coil is faulty
and should be replaced. If no faults are found, proceed
to the next step. Reconnect the wires to the coil.
Fig. 14. Ignition coil with integrated amplifier (power stage) used on
1988 and 1989 cars. Coil is mounted on right -hand side of
engine compartment, near the battery.
3. Check for power to the EZK control unit. Unplug the
connector from the EZK control unit and connect a voltmeter (VDC scale) between terminal 6 (+) and 20 (-) of
the connector. With the ignition on, there should be battery voltage. Turn the ignition off and reconnect the
connector. If no faults are found proceed to the next
step. If voltage is not present, use the diagrams shown
in 371 Wiring Diagrams, Fuses and Relays to check
for wiring faults.
4. Check for power to the amplifier. Peel back the boot
on the amplifier harness connector. Connect a voltmeter between the terminal 4 (+) and 2 (-) on fendermounted amplifiers (Fig. 15) or between terminals 3 (+)
and 2 (-) on coil-mounted amplifiers. With the ignition
on, there should be battery voltage. If no faults are
found proceed to the next step. If voltage is not present,
use the wiring diagrams to check for wiring faults from
the ignition switch.
Ignition coil resistance*
Model
I
Test terminals and
resistance
f-----------~-
except 1988-1989
I
1 and 15 - 0.5 to 0.9 Ohms
1 and center tower - 7200 to
8200
1
4 and 3 - 0.5 to 0.9 Ohms
4 and center tower - 7200 to
8200 Ohms
- - - - -
1988-1989
I
* measure with all wires disconnected from call
- - - - - - - - - - - - - - - - - -
~~
"----
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87423
I
Fig. 15. Voltmeter being used to check for voltage to EZK amplifier
(fender-mounter amplifier shown).
L
87424
Fig. 16. Coil circuits being tested using ohmmeter (conventional coil
shown).
ELECTRICAL TESTS AND FAUL T TRACING
Page 226
340-10
Ignition System
7. Check the amplifier switching function. Connect the
voltmeter between coil terminals 15 (+) and 1 (-) on
conventional coils or between terminal 3 (+) and 4 (-)
on coils with integrated amplifier. Turn the ignition on.
The voltage should rise to about 6 volts (DC) and then
drop to 0 volts within 1 to 2 seconds. If any faults are
found, replace the amplifier. If no faults are found proceed to the next step.
8. Check the pulse signal from the EZK control unit to
the amplifier. Peel back the rubber boot on the control
unit connector. Connect a voltmeter between the terminals 5 (+) and 2 (-) on fender-mounted amplifiers or between terminals 4 (+) and 2 (-) on coil mounted
amplifiers. While operating the starter, there should be
an oscillating voltage (pulses between 0 and 8 volts
(DC), average of 2.8 volts). If no faults are found, the
amplifier is faulty and should be replaced. If there is no
pulse, proceed to the next step.
NOTE
The engine can be tumed over using a wrench on the crankshaft pulley.
10. Check for voltage to the Hall sensor. Working from
the rear of the ElK control unit connector, connect a
voltmeter between terminal 4 (+) and 10 (-). See Fig.
18. With the ignition on, there should be battery voltage. If no faults are found, the Hall sensor is faulty and
should be replaced. If voltage is not present, the ElK
control unit is faulty.
NOTE
On all 1986-1988 cars, the Hall sensor is in the distributor. On
1989 and later cars, the Hall sensor is mounted behind the
crankshaft pulley. Hall sensor replacement procedures are
described below.
9. Check the Hall sensor signal to the EZK control
unit. Peel back the rubber boot on the ElK control unit
connector. Connect a voltmeter between terminal 24
(+) and 20 (-). See Fig. 17. Turn the ignition on and
slowly turn the engine over by hand. The voltage
should oscillate between 0.4 volts (DC) (or less) and
3.0 volts (or higher). If no faults are found, the ElK control unit is probably faulty and should be replaced. If
any faults are found, proceed to the next step.
Fig. 18. Voltmeter being used to check for voltage supply to Hall sensor from EZK control unit.
l
87425
Fig. 17. Voltmeter being used to check Hall sensor operation at EZK
control unit.
CAUTION
Tum the engine over only in the direction of nonnal rotation.
Otherwise damage to the timing chain and its components
may result. To detennine nonnal rotation, put the car in gear
and rock the car forward, noting the rotation of the ignition rotor, the flywheel, or a belt-driven component. As an altemative, briefly operate the starter.
ELECTRICAL TESTS AND FAULT TRACING
NOTE
If on 1986 and 1987 models, all electrical checks are as specified but the car still does not start, check the ignition pulse
amplifier on the main fuse relay panel. See Fig. 12 above. This
relay-like amplifier is designed to "amplify" the tachometer signal for more reliable control of electronic components affected
by the ignition system (LH fuel injection, fuel pump control,
etc.). To check the amplifier, simply remove it from its socket.
Then using a jumper wire, jumper the fuse/relay panel sockets
corresponding to relay tenninals TD-I and TD-O. Try to start
the engine. If the engine now runs, replace the pulse amplifier.
Page 227
Ignition System
COMPONENT REMOVAL AND
REPLACEMENT
NOTE
Spark plug replacement is covered in 1 LUBRICATION AND
MAINTENANCE. Spark plugs are replaced at regular intervals and should not be cleaned or regapped.
To replace distributor cap and rotor
340-11
3. Remove the vacuum hose from the vacuum diaphragm
and the harness connector from the Hall sensor, where
applicable.
NOTE
Turbo models have no mechanical advance in the distributor.
Mode!s with EZK have no vacuum or mechanicai advance.
4. Remove the distributor clamp-down bolt and bracket.
See Fig. 20.
1. Unhook the spring clips from the distributor cap and
pull off the cap. Leave the wires in the cap.
2. Remove the rotor by cracking it off the distributor shaft
using a slip-joint pliers. See Fig. 19.
NOTE
Replacement rotors may not always be glued in place. Check
to see if the rotor can be pulled off first.
Fig. 20. Distributor clamp-down bolt being removed.
5. Pull the distributor from the cylinder head. Inspect the
O-ring on the distributor shaft and replace if faulty.
6. Install the distributor into the cylinder head while rotating the rotor until the dog on the shaft engages the offset cutout in the camshaft. See Fig. 21.
Fig. 19. Ignition rotor being crushed to remove it from shaft.
3. Install a new rotor with a locking compound (Loctite 601
locking compound or equivalent).
4. To replace the distributor cap, clip the new cap into position. Then transfer one ignition wire at a time to maintain proper firing order of the spark plugs.
7. Install the clamp-down bracket and its mounting bolt.
Do not fully tighten the bolt.
8. Rotate the distributor housing until the matching marks
made earlier are aligned. Check and adjust ignition timing as described below.
Tightening torque
-Ignition distributor hold-down bolt .. 15 Nm (11 ft-Ib)
To remove and install distributor
1. Make matching marks on the base of the distributor
and the cylinder head.
2. Unhook the spring clips from the distributor cap and
pull off the cap. Leave the wires in the cap.
COMPONENT REMOVAL AND REPLACEMENT
Page 228
340-12
Ignition System
Fig. 22. Reid rotor circlip being removed.
Fig. 21. Offset dog on distributor shaft (arrow)
must engage cutout in camshaft.
Hall Sensor
Two different Hall sensors are used in the cars covered by
this manual. Replacement procedures vary between styles.
Hall sensor location
1986-1988 Non-Turbo
in distributor
1985 and later Turbo
1989-and later Non-turbo
behind crankshaft
Fig. 23. Hall sensor field rotor being removed.
NOTE
Distributor replacement parts, including the a rebuild kit for the
distributor-mounted Hall sensor, are available from an authorized Saab dealer.
To replace Hall sensor
(distributor-mounted sensor)
1. Remove the distributor as described above.
2. Thoroughly clean the distributor shaft, removing any
glue or other residues from the shaft.
3. Remove the field rotor circlip. See Fig. 22.
Fig. 24. Reid rotor locating pin (arrow),
4. lJsing a small2-jaw puller, carefully remove the field rotor. See Fig. 23. Remove and save the field rotor locating pin. See Fig. 24.
COMPONENT REMOVAL AND REPLACEMENT
Page 229
Ignition System
5. Remove from the distributor shaft the two circlips and
spacer from above the Hall sensor. Remove the plastic
cover.
340-13
To replace Hall sensor
(crankshaft-mounted sensor)
1. Disconnect the negative (-) battery cable.
6. Carefully pry off the plastic connector housing from the
side of the distributor. See Fig. 25. Lift the sensor out of
the distributor.
NOTE
Make sure the spacer undemeath the Hall sensor does not
come out with the sensor.
2. Remove all the V-belts from the crankshaft pulley. See
1 LUBRICATION AND MAINTENANCE for more information on removing V-belts.
3. While holding the flywheel stationary, remove the
crankshaft pulley center mounting bolt. Remove the
pulley and its woodruff key.
NOTE
A special flywheel holding fixture (Saab tool no. 83 92 987) is
available from an authorized Saab dealer.
4. If necessary remove the Hall sensor field rotor from the
pulley by removing the three bolts. See Fig. 27.
Fig. 25. Hall sensor connector housing being removed.
7. Install the new sensor into the distributor. Where applicable, make sure the locating pin on the sensor engages the hole in the diaphragm arm. See Fig. 26.
8. The remainder of installation is the reverse of removal.
Be sure to install the field rotor locating pin (see Fig.
24).
87434-531861
Fig. 27. Ignition field rotor being removed from rear of crankshaft pulley.
5. Disconnect the Hall sensor connector. The connector is
located below the oil dipstick tube. See Fig. 28.
6. Remove the Hall sensor bolts and remove the sensor.
See Fig. 29.
Installation is the reverse of removal. Use Loctite®270 on
the sensor mounting bolts. Reinstall the pulley and woodruff
key. Tighten the bolt while holding the flywheel steady.
Tightening torque
• crankshaft pulley bolt to crankshaft
1989
190 Nm (140 ft-Ib)
1991and later
175 Nm (128 ft-Ib)
Fig. 26. When installing sensor, engage pin on sensor with hole in vacuum diaphragm arm (arrows).
COMPONENT REMOVAL AND REPLACEMENT
Page 230
Ignition System
IGNITION TIMING
340-15
~ 850-875 r/min
On most models, ignition timing should be checked at regular service intervals as listed in 1 LUBRICATION AND MAINTENANCE. Timing should also be checked any time the
distributor position has been altered.
NOTE
On 1989 and later models with a crankshaft-mounted sensor,
checking and adjusting ignition timing at regular intervals is no
longer necessary.
r-, r-, /-, r-,
I~~
~-)~_)~_)',_)I~~~
To check and adjust ignition timing
87397 -53422
Fig. 32. When checking timing, idle speed must correct. Where appli
WARNING
cable, disconnect the vacuum hose (arrow).
The ignition systems installed on the cars covered by this
manual are high-energy systems operating in a dangerous
voltage range which could prove to be fatal if exposed terminals or live parts are contacted. Use extreme caution when
working on a vehicle with the ignition on or the engine running.
1. Connect a timing light and a tachometer according to
the manufacturer's instructions. Start the engine and
allow it to reach operating temperature.
2. If applicable, disconnect the vacuum advance hose
from the throttle housing. Check that the idle speed is
as specified. See Fig. 32. If idle speed is incorrect, adjust it as described in 240 Fuel Injection.
3. While pointing the timing light at the flywheel, check
that the timing marks are correctly aligned. See Fig. 33.
If the marks are not aligned, loosen the distributor
clamp-down bolt and slowly rotate the distributor until
the marks are aligned. Tighten the bolt.
Fig. 33. Ignition timing marks on flywheel and clutch cover (ar
rows). Clutch cover is in front of engine.
Ignition Timing
Tightening torque
• Turbo models (vacuum
hose disconnected)
• Non-turbo models
• Ignition distributor hold-down bolt ... 15 Nm (11ft-lb)
16°BTDC @ 850 rpm
14°BTDC @ 850 rpm
4. Turn the engine off. Disconnect the test equipment. Reconnect the vacuum hose, if applicable.
IGNITION TIMING