Table of contents: Procedure ↓ Visual inspection ↓
Procedure
The control unit cannot be tested at home. In practice, it very rarely fails. Sensors, switches and plugs break much more often, so if there is a malfunction, you should perform the following steps:
- Make sure the ignition is working properly.
- Check the fuel supply.
- Perform a visual inspection of the injection system components (see next paragraph).
- If the fault is not found, you should ask the self-diagnosis system, establish possible causes of the fault, check the parts suspected of fault.
Caution: When the injection system is completely switched off, you should first check the fuse. All current consumed by the injection system passes through it.
Visual inspection
Check vacuum hoses for leaks. All hoses connected to the injection system or to the intake manifold should be checked - from the thick brake booster hose to the thin vacuum hoses to the distributor.
Check the condition of the gasket under the injection system and the flange gaskets of the intake channels.
Additional air can penetrate into the injection system through leaks, which is not taken into account by the control unit and disrupts the mixture proportion. The mixture becomes uncontrollably leaner. As a result, interruptions in engine operation can occur, especially at idle.
Inspect the fuel lines for leaks.
If the plugs have been disconnected and connected frequently, or if they have become corroded, all of this can lead to an unreliable connection (bad contact).
Inspect the plugs on the system components. The contacts should not be bent, but only treated with a special compound for contacts.