Checking and adjusting the fuel injection system «MONO-JETRONIC»

So that when checking and adjusting the injection system «Mono-Jetronic» not to get injured and not to disable the components of the system, the following rules must be observed.

Do not allow the engine to run if the wire clamps are loosely attached to the battery terminals.

Do not disconnect the wires from the battery terminals while the engine is running.

It is necessary to disconnect the battery from the on-board network when charging it in a car from an external current source.

Do not start the engine using an external current source with a voltage of more than 12 V.

Do not disconnect the electrical connector of the electronic control unit with the ignition on. Before connecting the plug connectors, make sure that there are no damages and traces of oxidation on the contacts of the male and female parts, as well as that the connectors are connected securely. Make sure that the rubber seal of the pads and the fixing spring are present. Replace damaged spring.

Before working on a vehicle using electric welding. including the point, disconnect the connector of the electronic control unit.

Remove the electronic control unit. if the car will be exposed to temperatures over 80°C (e.g. before placing a freshly painted car in the drying chamber). Before checking the compression in the engine cylinders, disconnect the wire blocks from the injectors to prevent fuel from being supplied to them.

Do not check the wires and their connections with a test lamp.

Do not check «for a spark» the presence of voltage in the circuit.


Before checking the voltage, make sure that the battery is fully charged. Make sure the ignition is off before checking resistance.

On vehicles with an exhaust gas converter, the following rules must also be observed:

• use only unleaded gasoline;
• prevent complete consumption of fuel;
• in case of interruptions in the operation of the engine, it is recommended not to use the car and eliminate the malfunction as soon as possible; do not disconnect the wires from the spark plugs while the engine is running:
• when testing a car on a stand with running drums, ensure good airflow of the converter;
• when carrying out checks with the ignition system turned off or faulty, disconnect the wire blocks from the injectors.