Troubleshooting
When troubleshooting an engine, begin by checking the operation and inspecting the major systems. If the engine is not running properly, has a rough idle, or lacks acceleration, check the following major systems:
1. Electrical power:
- battery;
- burnout jumper;
- fuse.
2. Connections to ground
3. Fuel supply:
- fuel line;
- fuel filter;
- fuel pump.
4. Ignition system:
- spark plug;
- high voltage wires;
- ignition coil.
5. Emission control system:
- crankcase ventilation system;
- vacuum leak.
6. Other:
- setting the ignition timing;
- idle speed.
MFI system malfunctions are often caused by poor contacts in the wiring harness connectors. Therefore, check that all connectors are securely connected.
Checking the idle speed
Warning: Before checking the idle speed, make sure the spark plugs, fuel injectors, idle speed modulator (ISC), compression, etc. are in order.
Verification conditions
1. The engine must be warmed up to a coolant temperature of 80-95°C.
2. Headlights, parking lights, radiator fan and all electrical consumers must be switched off.
3. The gearbox must be set to neutral.
4. The steering wheel must be set to point straight ahead.
Examination
1. Connect a tachometer to the primary winding of the ignition coil or a scanner to the diagnostic connector.
2. Start the engine and let it run at idle speed.
3. Increase the crankshaft speed to 2000-3000 min⁻¹ for no more than 5 s, then let it idle for 2 min.
4. Use the tachometer to determine the idle speed.