By a simple test of the secondary voltage, it can be ascertained whether an ignition spark is produced at all.
The power supply to the ignition and injection systems passes through thermal fuses in brown, black and red holders (in the ignition unit). If the ignition system fails, these fuses should be checked (chapter «Body electrical system»).
Accurate visual inspection of the ignition system helps to identify the most common causes of failures (faulty wires and plugs, electrical breakdowns).
Only now it is necessary to check the ignition coil, the Hall sensor or the speed sensor or the ignition timing sensor one by one.
If all this did not lead to success, you need to interrogate the memory of the fault drive (In workshop).
Checking for Secondary Voltage
Right at the beginning, we check whether the ignition system produces an ignition spark:
Disconnect the high voltage wire from the spark plug, unscrew the spark plug.
Put the wire back on the spark plug and place it on the cylinder block in such a way that it has good contact with «weight» (corps). Even better, create an electrical circuit by connecting the spark plug threads to the engine with an auxiliary cable to «smoking».
Have an assistant turn the engine over with the starter.
«Shutdown» ignition by disconnecting plugs (arrows) on the electronic switches of the ignition coils, on the left for the example of models with 4- and 5-cylinder engines, on the right for the example of a 6-cylinder engine.
The illustration shows the ignition coil pack for 6-cylinder engines with the engine guard removed. The numbers on the high voltage connectors indicate to which cylinder which wire should be routed.
Checking the ignition system for sparking. For safety purposes, the spark plug must be electrically connected to the engine using an auxiliary cable, which is not shown here.
If a powerful spark overlap occurs on the spark plug electrode, then there is current in the ignition system. The main ignition control may not be set correctly (see the relevant section in this chapter).
If sparking does not occur, repeat the test with a spark plug of another cylinder. In the event that there is no sparking there, the entire ignition system should be fully checked.
Visual inspection of the ignition system
Are all terminals and plugs on the ignition coil, electronic ignition control unit or ignition and injection control unit and ignition distributor tightly fastened?
Has a contact come off in the multi-pin plug?
Has the sealing compound leaked out of the ignition coil? In this case, it's probably wrong
Are there any cracks or traces of carbon deposits on the ignition coil housing from spark breakdowns?
In addition, check whether the main cables and high-voltage wires are soldered securely and whether their insulation is intact.
Is there any damage to the distributor cap?
Are all parts of the ignition system clean and dry? Dirt contributes to electrical breakdowns.
Hint: connect and disconnect control devices only when the ignition is off.
Along with a complete failure of the ignition system due to a lack of power, too little voltage can also cause serious malfunctions!
Is the power to the ignition system OK?
Are the fuses ok?
Models with 4- and 5-cylinder engines: disconnect the plugs on the electronic switch next to the ignition coil.
Connect the measuring device to the disconnected plug between pin 1 (terminal 15) and pin 3 («weight»).
Turn on the ignition.
The voltmeter should show at least 11.5 V.
If the device does not show any voltage at all or is too weak, then the reason is in the wiring to the ignition switch.
The same can be said about the plug in a car equipped with a so-called high voltage transformer.
Models with 4-cylinder engines: carry out the same measurement at the black-blue wire of the Motronic or Digifant control unit.
Models with 5-cylinder engine: carry out the same measurement at the black-blue wire of the fully electronic ignition control unit.
And in these places the indicator should be at least 11.5 V.
Models with 6-cylinder engine: disconnect the white plug connection at the rear wall of the engine compartment (power supply for ignition coils), connect a measuring device between each of the three sockets of terminal 15 at the top of the plug connection and «weight».
Turn on the ignition.
Each measurement should show a minimum of 11.5 V.
If the device does not show any voltage at all or is too weak, then the reason is in the wiring to the ignition switch.
Carry out the same measurement at the black-green cable of the MPI / MPFI system control unit.
The indicator must be at least 11.5 V.
Causes of malfunctions
Prerequisite: battery is charged, fuses are OK.
Faulty ignition switch (chapter «Instruments and accessories»).
Break in the wiring between the ignition switch and the central switch and between the central switch and the coil (ami) ignition or between the central switch and the control unit. Check the passage of wires and plugs on the basis of the wiring diagrams placed in the book.
Checking the ignition coil. Models with 4- and 5-cylinder engines
A visual inspection of the ignition coil has already been carried out.
To test the resistance with the ignition off, disconnect all wires from the ignition coil. We measure the primary and secondary windings.
Use an accurate ohmmeter to measure the resistance between the ignition coil terminals 1/- and 15/+.
Standard resistance: 0.5-1.5 Ohm.
The next measurement is between terminals 1/- and 4.
Here the ohmmeter should show 5-9 kOhm.
If these indicators are not achieved, the ignition coil should be replaced.
With these measurements, it is not possible to determine a short circuit between the windings. Therefore, if despite the good results obtained, you still consider the ignition coil to be the cause of the problem, you must take the removed ignition coil to an auto electrical workshop for rechecking.
Checking the electronic switch. Models with 4- and 5-cylinder engines
It is impossible to test for functioning only a single electronic switch located next to the ignition coil. Therefore, you should proceed as follows:
Control test: Disconnect the plugs on the electronic switch next to the ignition coil.
Connect a voltmeter to the connectors between pin 2 (control) and pin 3 («weight»).
Turn the engine over with the starter.
The voltmeter should show at least 2 V.
Check the supply of the ignition system with power according to the scheme already described.
Check ignition coil, see next section.
If there is no sparking in the ignition system, despite the fact that the three tests mentioned above did not reveal any malfunctions, then the electronic switch is defective. In this case, you need to replace the electronic switch complete with the ignition coil.
High voltage transformer
In some 4-cylinder models, the ignition coil and electronic switch are assembled into one unit (high voltage transformer). The connections from terminals 1 and 15 of the ignition coil are located under a protective cover. Connection on «mass» (frame) passes directly through the body. According to the mode of action, it corresponds to an ignition coil with an electronic switch.
Checking the high voltage transformer
A visual check has already been made.
To check the resistance with the ignition off, disconnect the three-pin plug and the main high-voltage wire of the transformer. We measure the primary and secondary windings of the element with the coil.
Measure the resistance between the high voltage transformer terminals 1/- and 15/+.
Standard indicator: 0.5-0.7 Ohm.
The next measurement is between terminals 15 and 4.
Normative indicators: 3-4 kOhm.
If the specified values are not achieved, the transformer should be replaced.
With these measurements, it is not possible to recognize a short circuit between the windings. Therefore, you still consider the high voltage transformer to be the cause of the problem, you must take the removed transformer to an auto electrical workshop for rechecking.
To check the voltage, you will need a voltmeter, as well as auxiliary cables with test probes.
Connect the measuring cable to both external contacts of the three-pin plug of the high voltage transformer.
Turn on the ignition, the voltmeter should show approximately 12 V. If there is no voltage, you need to look for a cable break in the positive or negative wiring.
Switch off the ignition.
The photo shows the ignition coil of models equipped with 4- and 5-cylinder engines, with the correct terminal designations.
The figure shows the pin assignment of the connector on the electronic switch (important for checks).
Some models with 4-cylinder engines are equipped with similar high voltage transformers. Ignition coil (3) and electronic switch (2) combined here in one building. In this case, too, the corresponding terminal designations are indicated at the connections, with terminals 1 and 15 becoming accessible only after opening a small cover. The illustration also shows a three-pole plug.
Pulse test: fuse #17 in fuse box to prevent fuel being injected unnecessarily.
Connect the LED voltmeter with auxiliary cables and test probes to pins 2 and 3 of the transformer plug.
Ask an assistant to bring the starter.
The LEDs should flicker. If not, then the cause is in the Hall sensor or the control unit of the Mono-Motronic or Digifant injection system is faulty.
Switch off the ignition.
Checking ignition coils. Models with 6-cylinder engines
A visual inspection of the ignition coils has already been carried out.
To check resistance, disconnect all high voltage wires from ignition coils. We check the secondary winding of the coils.
Use an accurate ohmmeter to measure the resistance between the sockets of the high-voltage wires of the ignition system of the first and sixth cylinders (first coil).
Standard indicator: 9-14 kOhm.
The same measurement should be made between the sockets of the high-voltage wires of the second and fourth cylinders, as well as the sockets of the wires of the third and fifth cylinders (second and third coils).
If everything is in order, the next step is to check the secondary winding of the coils.
Disconnect the white plug connection near the rear wall of the engine compartment (ignition coil supply), connect the measuring device of your choice to one of the three contacts of terminal 15 at the top of the plug connection.
Disconnect the three-pole plug of the electronic switch (also near the rear wall of the engine compartment), connect the second wire of the ohmmeter in turn to all three terminals in the plug.
Standard indicator: for all three measurements, 0.5-1.0 ohms should be obtained.
If not, replace the ignition coil pack.
Checking the electronic switch. Models with 6-cylinder engine
Remove the plugs from all six injection nozzles.
Disconnect the 4-pole plug of the electronic switch (near the rear wall of the engine compartment).
Connect LED voltmeter to «mass».
Connect the free wire of the voltmeter in turn to contacts 1, 3 and 4 of the disconnected plug.
Electronic switch (arrow) ignition coils 6-cylinder engine is located at the rear wall of the engine compartment. The figure shows the pin assignment of a 4-pole plug. The pin assignment of the 3-pole plug is as shown in the figure on the previous page (4- and 5-cylinder engines).
The assistant turns the engine over with the starter each time.
The LED voltmeter should flash during all three measurements, otherwise the control should be checked or the electronic switch should be replaced.
Hall sensor test. Models with 4- and 5-cylinder engines
Disconnect the plugs of the electronic switch next to the ignition coil.
Pull off the rubber cap of the Hall sensor plug (on the side of the ignition distributor) with a plug connected, in order to make the contacts of the plug available.
Connect a voltmeter to terminal 2 (purple wire) and 3 (purple-brown wire) plug.
Turn on the ignition and turn the engine slowly by hand to rotate the perforated diaphragm (trigger) distributor, entered the Hall sensor and left it.
Watch the meter: it should show 0-0.5 V if the diaphragm is outside the Hall sensor. When the diaphragm is inside the Hall sensor, the reading should be at least 4V.
If there are no pulses, then you should check the power of the Hall sensor:
Disconnect the plugs from the distributor and connect a voltmeter to both external contacts of the plug.
Turn the ignition on, the voltmeter should now show at least 9 volts.
Otherwise, the control unit/wiring is faulty.
Hall sensor test. Models with 6-cylinder engine
Disconnect all injection nozzle plugs.
Pull off the rubber cap of the plug behind the Hall effect sensor (plug remains connected).
Check the presence of voltage with the ignition on between terminals 1 and 3 of the plug with an LED voltmeter (the terminals are marked on the plug).
Otherwise, check the wiring.
Connect an LED voltmeter between terminals 2 and 3.
Have an assistant turn the engine over with the starter.
The LED voltmeter should flash, in which case the Hall sensor is OK.
Hint: if the Hall sensor fails, it is not at all necessary to change the entire distributor. Hall sensor can be purchased separately.
Checking the crankshaft speed sensor. Models with 6-cylinder engines
The speed sensor is located above the flywheel ring gear. Its plug connection is directed upwards to the plug holder on the rear wall of the engine compartment, so it is not necessary to take measurements under the vehicle at all.
Check the passage of the wire from the sensor to the holder on the rear wall of the engine compartment, check the reliability of the plug connection and the insulation on the wires.
Electrical check with a drain ohmmeter:
Disconnect the black three-pole plug connection and connect an ohmmeter to the sensor between pins 1 and 2 (see picture).
The ohmmeter should show 1 kOhm, otherwise the sensor is faulty.
The third contact is the cable shield.
Connect an ohmmeter to check the shielding now between pins 1 and 3 and also between pins 2 and 3.
The ohmmeter should show ∞ ohm, otherwise the sensor is faulty.
Hint: a further check is to remove the sensor and clean its end face. Dirt or oil in this area interferes with work. Please note: never remove the sensor holder, only the sensor itself. If the sensor fastenings have been loosened, it must be re-adjusted in the workshop with a special tool.
Right: plug connections at the rear right of the engine compartment on a 6-cylinder model:
1 - for heating the right lambda probe;
2 - for the ignition coil (supply wiring);
3 - for the signal of the lambda probe (right lambda probe; the plug connection is behind the fastener);
4 - for the detonation combustion sensor I;
5 - for the engine shaft speed sensor;
6 - for the ignition timing sensor.
Bottom: The illustration shows the pin assignment of the engine speed and ignition timing sensor plug.
Open the ignition distributor: press out the retaining clips with a screwdriver (arrows), lift the distributor cap (4) from the body (3), remove the distributor slider (1), remove the dust cover (2).
Checking the ignition timing sensor. For 6-cylinder engine
The ignition timing sensor is installed on the left rear directly in the cylinder block. It should be checked through the gray three-pole plug connection on the rear wall of the engine compartment. The test itself is similar to checking the engine speed sensor, which is described in the previous section.
Checking the control unit
For control unit (electronic ignition system or ignition and injection system) there is no verification method in the usual sense of the word. However, you can find the cause of the malfunction after polling the memory of the fault memory (chapter «Regular maintenance»). The control unit for the electronic ignition system is located under the front passenger footwell trim (chapter «Body electrical system»).
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