General information
Petrol engines are equipped with an electronic injection system. DOHC 1.0 and 1.2L engines have a Bosch-Motronic injection system, other engines are equipped with Opel MulTec ignition and injection systems. MulTec technology is based on a single control of ignition and injection through a common control unit.
Various variants of the MulTec injection system are installed. For 1.2 and 1.4 liter engines with 45 and 60 hp respectively the MulTec system is designed as a central injection system with one injector for all cylinders. The distribution of the mixture over the cylinders occurs, as in a conventional carburetor engine, through the intake manifold.
On 1.4 liter engine with 82 hp the MulTec-M system is used. Here «M» means distributed injection (MPI). Fuel is injected through 4 injectors into the intake manifold just before the intake valves. On 1.4 and 1.6 liter engines with 90 hp the amount of injected fuel for each cylinder is calculated separately (sequential injection, SFI), so the injection system is referred to as MulTec-S.
All injection systems are highly reliable and require no special maintenance.
Safety measures when working on the engine management system
Remember that the fuel inside the power system path with the engine running and the ignition on is under pressure. Residual overpressure continues to be retained in the system for some time after switching off the ignition and must be released before disconnecting the components / disconnecting the fittings!
Do not touch or disconnect the ignition wiring harness while the engine/starter is running.
Persons with an implanted pacemaker must never be allowed to service the elements of the ignition system!
Connection and disconnection of measuring instruments must also be carried out with the ignition off.
The fuel lines must be disconnected with the ignition off.
When checking the compression pressure in the cylinders, the power and ignition systems must be turned off (see the relevant section of Chapter Engines).
See also the list of safety precautions in Section Supply system of this chapter.
Notes on checks of the engine management system
When looking for the causes of failures, first of all, it is necessary to remove diagnostic codes from the processor memory, as well as check the tightness of the connection of the vacuum lines.
For reliable functioning of all electrical elements of the system, a voltage of at least 11.5 V is required.
If, after the search for and elimination of the causes of failures, the engine stalls immediately after starting, the cause of this phenomenon may be the blocking of the anti-theft system - interrogate the processor memory, if necessary, adjust the corresponding control unit.
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