15-540 Testing electronic ignition system with variable characteristics (EZL)
Preceding work:
Testing, adjusting engine (07.3-110)
Operation No. of operation texts and work units or standard texts and flat rates: 15-1250
Precondition for test
Spark plugs, ignition cables, distributor rotor and distributor cap in proper mechanical and electrical order.
Test e. g. by visual inspection, measuring resistance and ignition oscilloscope.
P15-0424-59
Connection diagram for engine tester with oscilloscope
N1/2 EZL control unitR4 Spark plugsR16 Resistance trimming plug (EZL)
B11/2 Coolant temperature sensor (EZL/KE)B17/1 EZL intake air temperature sensorG1 BatteryL5 Crankshaft position sensor
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T1 Ignition coilX11 Diagnosis socket/terminal block terminal TD1 Segments on flywheel/driver disc2 Vacuum line030 Engine tester with oscilloscope
S5/3 High voltage distributorS29/2 Full load/idle speed detection throttle valve
switchS65 Transmission overload protection switch
(only engines 102.983/99)
Note
Pay attention to the safety precautions (15-505) when performing work on the ignition system. Switch off ignition when unplugging and plugging in the connectors at the EZL control unit.
The test is split up into two sections:
A. Engine not runningThe basic functions of the ignition system are tested in this section.
B. Engine running
Fault sources in the ignition advance or at the
appropriate components may affect the handling of the vehicle.
If a complaint is received regarding the handling of the vehicle, first of all test the ignition system. Then, continue troubleshooting at the KE injection system.
Special tools
Commercially available testers
Multimeter e. g. Sun, DMM-5Fluke, Multimeter 23Hermann, Avometer 2003
Engine tester e. g. Hermann, Datascope 9800Bosch, MOT 301/400Sun, 2110BEAR, D AC E
Test data
Resistances (test data from 0-100° C)
Ignition coil primary (terminals 1 and 15) W 0.3-0.6
Ignition coil secondary (terminals 1 and 4) kW 8-13
Position sensor coil resistance (terminals 7 and 31d) W
insulation (terminal 7 and ground) kW
680-1200U 200
Distributor cap per terminal, W
distributor rotor,
spark plug connector
700-1300
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Voltages, engine not running, ignition switched on
Terminals 15 and 31 (contacts 5 and 2 diagnosis socket) V Battery voltage
Between terminals 15 and 1(contacts 5 and 4 diagnosis socket) V 0
4-pin round connector terminals 15 and 31 V Battery voltage
4-pin round connector terminals 16 and 31 V Battery voltage
Dwell angle
At starter speed 9-49° or 10-54%
At 3200/min 27-54° or 30-60%
Ignition point at starter speed in ° CS TDC F2°
Test ignition points with engine running (15-515).
Resistances of resistance trimming plug (R16)
Position Resistance EZL resistance trimming plug
"EZL-ECE" "EZL-KAT" "EZL"(102.983Std.)
"EZ-ECE-S" (102.983 R?F)
"EZL-KAT"autom.
"EZL-KAT"man.
A 1 W S 1 1 1 - -
B 2.4 kW 2 2 2 S S -
C 1.3 kW N 3 3 N - S
D 750 W 4 S 4 4 4 4
E 470 W 5 5 5 5 N N
F 220 W 6 N 6 6 6 6
G 0 W 7 7 7 7 - -
A. Engine not running
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Note
If the specified value of a test step, e. g. test step 1.0, is in order, continue immediately with test step 2.0.
If the specified value of step 1.0 is not in order, it is then necessary to continue with step 1.1.
Key to symbols:
c Multimeter direct voltage mode
b Multimeter resistance mode
e Oscilloscope
w Contact
v Connector
o Ground
On/off ratio readout
Test step/Test scope
Test connection Operation/Requirement
Specifi-
cation
Possible cause/Remedy
- 1.0
Voltage supply
N1/2
31 w cL15
Ignition: ON Battery voltage
Test wiring and contacts according to wiring diagram (from battery via ignition lock to EZL control unit).
2.0
Crankshaft position sensor L5
L5
31d wb L 7
Ignition: OFFDetach crankshaft position sensor connector at EZL control unit.
680-
1200 W
Replace crankshaft position sensor (L5).
On/off ratio readout
Test step/Test scope
Test connection Operation/Requirement
Specifi-
cation
Possible cause/Remedy
- 2.1 L5
31d wb L 7
Detach crankshaft position sensor connector at EZL control unit.
Engine: Start
see diagram
US U1 V
Signal too small/no signal: replace position sensor. Different voltage height: test segments. Replace EZL control unit.
- 2.2
Insulation of sensor coil
L5
w b L 7
o
Detach crankshaft position sensor connector at EZL control unit.
U200 kW Replace crankshaft position sensor.
- 3.0Dwell angle
Engine tester Engine: Start 9°-49°or 10-54%
Dwell angle not to tolerance:replace EZL control unit. No dwell angle: test stall current cutoff.
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- 4.1Stall current cutoff
T1
Kl. 1 c Kl. 15
T1
Kl. 1 c Kl. 15
Ignition: ON
Engine: Start
0V
0V
>0V
Replace EZL control unit and ignition coil.
Test wiring and contacts from EZL control unit to ignition coil or replace EZL control unit. Replace ignition coil.
- 4.2Ignition coil primary T1
T1
Kl. 1 b Kl. 15
Ignition: OFF
Unscrew wiring at ignition coil.
0.3-0.6 W
Replace ignition coil.
On/off ratio readout
Test step/Test scope
Test connection Operation/Requirement
Specifi-
cation
Possible cause/Remedy
- 5.0
Primary current
Engine tester
eScope image:primary parade
Engine: Start >200 V Replace EZL control unit.
- 6.0Primary current limiting
Engine tester
eScope image:Secondary overlap
Engine: Start see diagramReplace EZL control unit.
- 7.0Ignition voltage at terminal 4 ignition coil
Engine tester
eScope image:Secondary parade
Engine: Start U8 kV Test ignition cable terminal 4, distributor rotor, distributor cap and ignition coil.
- 7.1Ignition cable terminal 4
T1 S5/3
Kl. 4 b Kl. 4
Ignition: OFFDetach ignition cable terminal 4 at ignition coil and distributor cap.
<1 W Replace ignition cable terminal 4.
- 7.2Distributor rotor
Distributor
rotor
bMiddle Peak
Ignition: OFFRemove distributor cap.
700-1300 W
and visual inspection
Replace distributor rotor.
- 7.3Distributor cap
S5/3
bKl. 4 Carbon
Ignition: OFFDistributor cap removed and detach ignition cable terminal 4.
700-1300 W
per terminal and visual inspection
Replace distributor cap.
On/off ratio readout
Test step/Test scope
Test connection Operation/Requirement
Specifi-
cation
Possible cause/Remedy
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- 7.4Ignition coil secondary T1
T1
Kl. 4 b Kl. 1
Ignition: OFFUnscrew cables at ignition coil.
8-13 kW Replace ignition coil.
- 8.0Ignition voltage at single cylinder
Engine tester
eScope image:Secondary paradeHigh voltage clamp at cylinder ignition
cable (e. g. cylinder 3)
Engine: Start >6 kV Test distributor cap,distributor rotor,ignition cables with spark plugs.
- 8.1
Ignition cable with spark plug connector
bIgnition Spark
cable plug
connector
Ignition: OFFDetach ignition cable with spark plug connector at spark plug and distributor.
700-1300 W Replace ignition cable with spark plug connector.
- 8.2Spark plugs
Visual inspection Ignition: OFFRemove spark plug.
Electrode gap0.8 mm
Replace according to condition.
Test A completed.
B. Engine running
Pay attention to safety precautions (15-505).
On/off ratio readout
Test step/Test scope
Test connection Operation/Requirement
Specifi-
cation
Possible cause/Remedy
- 1.0
Ignition point
Engine tester Engine: Test at normal operating temperature at specified speeds and with/without vacuum.
see table (15-515)
Resistance trimming plug, coolant temperature sensor, throttle valve switch, vacuum advance, transmission overload protection (102.983/99).
- 1.1Resistance trimming plug (R16)
N1/2
o b L 3
Sensor
connector4-pin
Ignition: OFF
Detach sensor connector at EZL control unit. Pay attention to assignment engine/ resistance trimming plug.
depending on resist-
ance trimming plug setting, see table
Resistance trimming plug, cables, contacts.
- 1.1.1Resistance trimming plug (R16)
R16
v b KMiddle A-G
Ignition: OFFDetach resistance trimming plug.
see table Resistance trimming plug
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- 1.1.2
Cables and contacts
R16 N1/2
w b L 3
Sensorconnector
4-pin
R16
o b L
Ignition: OFFDetach resistance trimming plug. Detach sensor connector at EZL control unit.
> 1 W
>1 W
Replace cables or contacts.
Test negative cable to W11 or W10, replace.
On/off ratio readout
Test step/Test scope
Test connection Operation/Requirement
Specifi-
cation
Possible cause/Remedy
- 1.2Coolant temperature sensor (B11/2)
N1/2
o b L 1
Sensorconnector
4-pin
Ignition: OFF
Detach sensor connector at EZL control unit
at
80 °C290-360 Wfurther values, see diagram
Coolant temperature sensor (B11/2) Cables, contacts.
- 1.2.1
Coolant temperature sensor (B11/2)
B11/2
(2-pin)
o b LGreen/black
cable
B11/2
(4-pin)
v b K
Ignition: OFF
Detach sensor connector at EZL control unit
measure 2B diagonally
Replace coolant temperature sensor (B11/2) (07.3-251).
Replace coolant temperature sensor (B11/2) (07.3-251).
- 1.2.2
Cables and contacts
B11/2 N1/2
w b L 1
Green/ Sensorblack connectorcable 4-pin
Ignition: OFF
Detach connector at temperature sensor and sensor connector at EZL control unit.
<1 W
see note
Replace cables or contacts.
- 1.3
Throttle valve switch idle speed detection
S29/2x
2 v b K 1
Ignition: OFF
Detach coupling (S29/2x).
Idle position: < 1W
Other positions: 1
Set or replace throttle valve switch. Open circuit.
On/off ratio readout
Test step/Test scope
Test connection Operation/Requirement
Specifi-
cation
Possible cause/Remedy
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- 1.3.1
Cables and contacts
N1/2 N3
2 w bL13
Sensorconnector4-pin
Ignition: OFF
Detach sensor connector at EZL control unit and KE control unit.
< 1W Replace cable or contact.
- 1.4
Vacuum advance
Engine tester Engine: normal operating temperature, speed 1500/min. Detach vacuum hose at EZL control unit.
Fit on vacuum hose at EZL control unit.
Ignition point retarded
Ignition point advanced
Vacuum hose leaking.Connection at intake manifold blocked.Pressure sensor in EZL control unit faulty.
- 1.5 L5
31d we L 7
Detach crankshaft position sensor connector at EZL control unit. Engine: Start
see diagram
US U 1V
Different voltage heights:Test segments (visual inspection)Replace flywheel/driver disc with segments.
On/off ratio readout
Test step/Test scope
Test connection Operation/Requirement
Specifi-
cation
Possible cause/Remedy
- 1.6
Transmission overload protection, only engine 102.983/99 with automatic transmission
N1/2
o b L 4
Sensorconnector
4-pin
Depress
parking brake.
Pay attention
to safety
precautions.
Engine: StartIdle speed selector lever
position: "D"
Selector lever position:"P" or "N"
< 1W
1
Transmission overload protection switch (S65) CablesContacts
Transmission overload protection switch (S65) CablesContacts
- 1.6.1
Transmission overload protection switch (S65)
S65
v b K
Detach
connector at
transmission
overload
protection
switch S65.
Depress
parking brake.
Pay attention
to safety
precautions. Engine: Start Idle speed
selector lever
position "D"
Selector lever position:"P" or "N"
< 1W
1
Replace transmission overload protection switch (S65).
Replace transmission overload protection switch (S65).
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On/off ratio readout
Test step/Test scope
Test connection Operation/Requirement
Specifi-
cation
Possible cause/Remedy
- 1.6.2
Cables and contacts
S65 N1/2
w b L 4
Sensorconnector
4-pin
S65
w b o
Ignition: OFFDetach
connector at
transmission
overload
protection
switch (S65)
and EZL
control unit
(N1/2).
Ignition: OFFDetach connector at transmission overload protection switch (S65) and EZL control unit (N1/2).
< 1W
< 1W
Replace cable or contact.
Replace cable or contact.
- 2.0Dwell angle
Engine tester Engine speed
3200/min,
normal
operating
temperature.
Detach sensor
connector at
EZL control
unit and
vacuum line.
Engine: Start
27-54°or 30-60%
Replace EZL control unit.
- 3.0High voltage distributor/ distributor rotor
Visual inspection Ignition: OFFRemove distributor cap.
- Distributor cap,distributor rotor has cracks, interference suppression resistors faulty.
On/off ratio readout
Test step/Test scope
Test connection Operation/Requirement
Specifi-
cation
Possible cause/Remedy
- 3.1Distributor cap
S5/3
bIgnition: OFFRemove distributor cap.
700-1300 Wper terminal
Replace distributor cap.
- 3.2Distributor rotor
Distributor
rotor
bMiddle Peak
Ignition: OFFRemove distributor cap.
700-1300 Wand visual inspection
Replace distributor rotor.
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- 4.0
Scope images
Engine tester
eScope imagesParadeOverlapRaster
Engine: StartIdling speed.
see Diagnosis Manual Engine Volume 1
Ignition coilDistributorIgnition cablesSpark plugs
Test B completed.
EZL ignition control unit (N1/2)1 Vacuum connection
2 Coaxial connector for control cable from position sensor3 4-pin sensor connector
1 Coolant temperature sensor2 Throttle valve switch3 EZL resistance trimming plug4 not assigned (cable ends in harness
or intake air temperature sensor)4 4-pin supply connector
15 = Terminal 1516 = Ignition coil terminal 1TD = TD signal31 = Ground P15-2193-13
Crankshaft position sensor signal L5t1 1st segmentt2 2nd segmentd Period for one crankshaft
revolutionUS Voltage (U1V) P15-0216-13
Crankshaft position sensor connector L5Test resistance or voltage signal between connection 7 and 31d.
P15-0240-13
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Current limiting
P15-0244-55
Notes regarding testCoolant temperature sensor (B11/2)
Diagram of coolant temperature sensor (B11/2)
P15-0237-15
4-pin coolant temperature sensor
Pin assignment of coupling:1=EZL temperature sensor2=KE temperature sensor3=Engine ground at intake manifold for EZL4=KE control unit ground
Note
National version I 1988 without coupling
designations.
P07-2022-13
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When testing the coolant temperature sensor, measure the resistances 2B diagonally and compare.
P15-0171-13
Note regarding ignition distributorImproved distributor rotor with polyamid bush.
Production breakpoint: January 1989
Model Engine Engine end No. manual transmission
Engine end No. automatic transmission
124.023124.043124.083
102.982 130477 127198
201.024201.028
102.962102.985
21149830070
10889878183
Note regarding crankshaft position sensorPosition sensor of a further manufacturer.
Production breakpoint: October 1989
Model Engine Engine end No. manual transmission
Engine end No. automatic transmission
124.021124.081
124.023124.043124.083
102.963
102.982
041939
150880
011638
153461
201.035 102.990 002490 001002
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P15-0212-57A
EZL wiring diagram, engines 102.962/963/982/985 R?F/KAT
a To KE control unit, contact 13b To injection system intake air temperature sensorc To KE control unit contact 5d To KE control unit contact 21e Voltage supply terminal 30
Model 124: to fuse 9 via engine plug connection (X26), contact 3Model 201: to fuse 13 via electrical center coupling S, contact 11
f Voltage supply, terminal 15, unfused Model 124: engine plug connection (X26), contact 1Model 201: electrical center coupling S, contact 4
g Cable ends in wiring harnessh Equipment with terminal TD (e. g. tachometer,
fuel pump relay, KE control unit, compressor cutoff control unit)
z Connector sleeve (soldered connector in wiring harness)
B11/2 Coolant temperature sensor (EZL/KE/2 E-E)L5 Crankshaft position sensorN1/2 Transistorized ignition control unit (EZL)R16 Resistance trimming plug (EZL)S5/3 High voltage distributorS29/2 Full load/idle speed detection throttle valve
switch S29/2x Full load/idle speed detection throttle valve
switch plug connectionT1 Ignition coilW3 Ground, front left wheelhouse (ignition coil)W10 Battery groundW11 Engine ground (electric cable bolted on)X11 Diagnosis socket/terminal block terminal TD
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P15-0210-57A
EZL wiring diagram, engines 102.91/96/98 KAT as of 09/89
a To KE control unit contact 13b To KE control unit contact 7 (ground)c To KE control unit contact 5d To KE control unit contact 21e Voltage supply terminal 30
Model 124: to fuse 9 via engine plug connection (X26), contact 3Model 201: to fuse 13 via electrical center coupling S, contact 11
f Voltage supply terminal 15, unfused Model 124: engine plug connection (X26), contact 1Model 201: electrical center coupling S, contact 4
h Equipment with terminal TD (e. g. tachometer, fuel pump relay, KE control unit, compressor cutoff control unit)
z Connector sleeve (soldered connector in wiring harness)
B11/2 Coolant temperature sensor (EZL/KE/2 E-E)B17/1 Intake air temperature sensor (EZL)L5 Crankshaft position sensorN1/2 Transistorized ignition control unit (EZL)R16 Resistance trimming plug (EZL)S5/3 High voltage distributorS29/2 Full load/idle speed detection throttle valve
switchS29/2x1 Full load/idle speed detection throttle valve
switch plug connectionT1 Ignition coilW3 Ground, front left wheelhouse (ignition coil)W10 Battery groundW11 Engine ground (electric cable bolted on)X11 Diagnosis socket/terminal block terminal TD
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P15-0211-57A
EZL wiring diagram, engine 102.983 with automatic transmission
a Voltage supply terminal 30 to fuse 13 via electrical center coupling S, contact 11
b Voltage supply terminal 15, unfused, electrical center coupling S, contact 4
c To KE control unit contact 13d To KE control unit contact 5e To KE control unit contact 21f Voltage supply terminal 15, fused, fuse 10
looped via left heated washer nozzle or soldered connector in wiring harness
h Equipment with terminal TD (e. g. tachometer, fuel pump relay, KE control unit, compressor cutout control unit)
z Connector sleeve (soldered connector in wiring harness)
B11/2 Coolant temperature sensor (EZL/KE/2 E-E)B17/1 Intake air temperature sensor (EZL)L5 Crankshaft position sensorN1/2 Transistorized ignition control unit (EZL)R16 Resistance trimming plug (EZL)S5/3 High voltage distributorS29/2 Full load/idle speed detection throttle valve
switchS29/2x1 Full load/idle speed detection throttle valve
switch plug connectionS65 Transmission overload protection switchT1 Ignition coilW3 Ground, front left wheelhouse (ignition coil)W10 Battery groundW11 Engine ground (electric cable bolted on)X11 Diagnosis socket/terminal block terminal TDX26/4 Taillamp wiring harness/engine wiring harness
plug connection, 4-pin
NoteS65 and X26/4 not applicable with manual transmission.
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P15-0425-55
EZL wiring diagram, engine 102.99 with automatic transmission
a Voltage supply terminal 30 to fuse 13 via electrical center coupling S, contact 11
b Voltage supply terminal 15, unfused, electrical center coupling S, contact 4
c To KE control unit contact 13d To KE control unit contact 5e To KE control unit contact 7 (ground)f To KE control unit contact 21g Voltage supply terminal 15, fused, fuse 10
looped via tachometerh Equipment with terminal TD (e. g. tachometer,
fuel pump relay, KE control unit, compressor cutout control unit)
z Connector sleeve (soldered connector in wiring harness)
B11/2 Coolant temperature sensor (EZL/KE/2 E-E)B17/1 Intake air temperature sensor (EZL)L5 Crankshaft position sensorN1/2 Transistorized ignition control unit (EZL)R16 Resistance trimming plug (EZL)S5/3 High voltage distributorS29/2 Full load/idle speed detection throttle valve
switchS29/2x1 Full load/idle speed detection throttle valve
switch plug connectionS65 Transmission overload protection switchT1 Ignition coilW3 Ground, front left wheelhouse (ignition coil)W11 Engine ground (electric cable bolted on)X11 Diagnosis socket/terminal block terminal TDX26/4 Taillamp wiring harness/engine wiring harness
plug connection, 4-pin
NoteS65 and X26/4 not applicable with manual transmission.
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