Engine fault diagnostics (Renault 19)

Troubleshooting

The following checks assume that the engine has no mechanical damage, but has stalled and will not start.

For a diesel engine, the main condition is that when starting, the engine warms up until the preheating device indicator lamp goes out.

Does the starter turn the engine?

If it does not turn or turns slowly, read the section "Sources of Electrical Equipment Failure". If the motor turns, you need to answer the following questions to further troubleshoot the problem:

Is there a spark from the spark plugs?

Remove the spark plug wire, unscrew the spark plug, reconnect the wire and place it on bare metal. Have an assistant crank the engine. Do not touch the spark plug wire or spark plug, see "LEZ Ignition System Safety Precautions" in the "Ignition System" chapter. Are there sparks? If not, see "Sources of Ignition Failure".

Is fuel injected in a petrol engine?

Disconnect the fuel supply hose of the injection system (multipoint injection) and lower it into the container (cover cap from a warning triangle). Ask an assistant to briefly turn on the starter.

Gasoline appears in the tank - the fuel system is working properly, but the injectors may be defective.

No petrol - read on for information on fuel system problems.

Is diesel fuel reaching the injector?

Use a SW 17 wrench to loosen the fuel line nut to the injector. Ask an assistant to turn on the starter. Is fuel coming from the injector? If so, the fuel supply is probably OK. Then read the next question. If fuel is not coming, read "Sources of Fuel Supply Malfunction".

Is the diesel preheater working?

Connect a test lamp to the main electrical connection at the glow plugs; and the other wire of the lamp to ground. Ask an assistant to turn the ignition key to the "warm up" position.

Is the light on? If it does not light, even though the engine is cold, the preheater is faulty. If it lights, the power supply to the glow plugs is OK. However, the glow plugs themselves may be faulty. Read about this in the section "Sources of Preheater Failure".

Checking a gasoline engine by visual inspection

• Has the wire plug slipped on any parts of the ignition or injection system?
• Check the tightness of the high-tension wires and whether they are properly placed on the spark plugs (the ignition must be off!).
• Are all low pressure hoses in the engine compartment connected to the appropriate fittings?
• Is there any condensation on the ignition coil or ignition system components? All ignition system components must be dry.
• Is there a smell of gasoline in the engine compartment? Is the fuel hose loose or completely loose?

Sources of electrical faults in petrol and diesel engines

• The indicator lights go out when you turn the key: the battery is discharged or weakened due to "age", there is possibly a short circuit in the starter.
• The indicator lights remain on when the key is turned: the white wire has come off the starter magnetic switch, the magnetic switch is faulty, the starter is faulty or the graphite brushes are worn out, or the B2 contact terminal in the ignition switch is faulty.
• The indicator lights do not light: the battery is completely discharged, the main starter wire has come off, or the battery terminals have become loose and oxidized.

Sources of fuel supply faults

If fuel does not flow from the injection system and, accordingly, the diesel injectors during the described check, the following reasons for the malfunction may be present:

All engines

• No fuel in the tank (don't laugh, check it out!).
• The fuel line is broken or clogged.
• The fuel filter is clogged.

Petrol engines

• The electric fuel pump does not work.
• Check all electrical pin connections. Has a single wire in a multi-pin connection popped out or broken?

Diesel only

• The shut-off valve of the diesel high-pressure fuel pump is faulty and blocks the flow of fuel to the injectors.
• During assembly, the two hollow screws for the fuel inlet and outlet were mixed up in the high-pressure fuel pump of the diesel engine. The hollow screw for the fuel outlet is marked "OUT".
• The fuel filter or fuel lines are clogged, or the fuel has thickened in the cold. This can be determined by the transparent fuel lines in the engine compartment. If the lines are empty or there are large air bubbles, then the fuel supply is disrupted.

Note: Recommendation: other sources of faults that occur much less frequently in the fuel and injection system of petrol and diesel engines can be found in the troubleshooting guide in the relevant chapter.

Sources of ignition faults

• Are all plug connectors in the area of the ignition coil, control unit and, accordingly, the ignition module connected correctly?
• Are there any cracks in the distributor cap or ignition coil housing, or traces of carbon deposits from spark breakdown?
• As a last resort, the only option left is to check the ignition system, see the relevant chapter in the section "Troubleshooting the ignition system".

Sources of Preheater Faults

The preheating device can be tested with a test lamp. If the preheating device is defective, see the relevant chapter for testing methods.

In any case, a serviceable engine can be started without using a preheating device by cranking it longer with the starter, unless the outside temperature is below zero. If it is below zero, then only towing can help.