Table of contents: Troubleshooting sequence ↓ First, a visual check ↓ The reason for the failure is the… ↓ The reason for the failure is the… ↓ The reason for the failure is the… ↓
When troubleshooting, we assume that there is no mechanical damage to the engine. In addition, we assume that the engine has suddenly stopped or does not start.
Troubleshooting sequence
Does the starter work?
If the starter does not turn on or turns poorly, read on to the section "Reason for failure - electrical system". If, on the contrary, it confidently turns the engine, you need to answer the following questions in turn in order to further narrow the search.
Do spark plugs produce a spark?
Disconnect the wire tip from one of the spark plugs, unscrew the spark plug, insert it into the tip. Now connect the spark plug with an auxiliary cable for the "cigarette lighter" to the cylinder block (the auxiliary cable is not shown in the illustration for better clarity). Ask an assistant to turn the starter. Do not touch the high-voltage wire or spark plug - it is dangerous! Are sparks visible? If yes, move on to the next question. If not, read on to the section "Reason for failure - ignition system".
Is fuel entering the injection system?
Disconnect the fuel supply line from the fuel filter at the rear right in the engine compartment. Caution: On models with a 4- and 5-cylinder KE-Jetrinic / Motronic engine, a relatively large amount of fuel may be ejected under high pressure. Therefore, when loosening the connection, place a thick rag on the nipple. You can extend the fuel supply line with a hose and lower its end into a container. Ask an assistant to briefly crank the starter.
If gasoline is supplied, then the fuel pump should work. If gasoline is supplied, then the injection system remains as the only source of malfunctions. Or the fuel pump, although working, does not provide the required pressure.
First, a visual check
- Has the wire tip come loose from any element of the ignition or injection system?
- Check the high-tension wires to the ignition coil, distributor and spark plug tips (the ignition must not be on!) for tightness of fit.
- Are all vacuum hoses in the engine compartment connected to the appropriate fittings?
- Is there condensation on or under the distributor cap? All ignition system components, including the ignition coil, must be clean and dry, otherwise there is a high risk of current leakage and breakdowns due to overvoltage.
- Smell of gasoline in the engine compartment? Check the fuel line for leaks and tightness.
The reason for the failure is the electrical system
- The indicators on the dashboard do not light or do not flash when the ignition is on: the battery is completely discharged or the battery terminals are loose.
- The indicators go out when the starter is turned on: the battery is significantly discharged or has already exhausted its resource, or there is an interturn short circuit in the starter.
- The indicator light becomes dimmer when the key is turned; the starter does not turn: the retractor relay is jammed or faulty; the starter may be faulty.
- When turning the key, the indicators light up or flash normally; the starter does not turn: defective contact of terminal 50 in the ignition switch, weak contact in the wiring to terminal 50 on the retractor relay, or a faulty retractor relay.
The reason for the failure is the ignition system
- Are all ignition coil and distributor wire ends installed correctly?
- Are there any cracks in the ignition coil housing or traces of burning from a spark?
- Remove the distributor cap. Can you find any traces of current leakage on its inside? Does the contact carbon in the middle of the cap spring well? Are traces of copper corrosion visible?
- If everything described above is in good working order, only a complete check of the entire ignition system will help.
The reason for the failure is the fuel supply system
- Check if there is petrol in the fuel tank. An empty petrol tank is not such a ridiculous idea as it may seem at first glance. The lack of fuel is detected primarily by interruptions in the engine operation when turning.
- Faulty fuel pump.
- Clogged fuel filter.
- If the fuel supply is correct, especially in case of persistent starting problems, the injection system should be checked.
(The original version is on the portal: audimanual.ru)