Contents: Troubleshooting the Fuel System ⇓ Troubleshooting the Engine Starting…⇓ Troubleshooting the Fuel Tank and…⇓
Troubleshooting the Fuel System
Sign | Probable cause | Method of elimination |
| The engine does not start | The engine crankshaft is turned slowly by the starter | Repair the engine starting system or charge the battery so that the starter turns the engine crankshaft at a frequency of at least 150 min⁻¹ |
| No voltage in glow plug supply bus | If the test lamp does not show voltage when the ignition key is turned to the "ON" position, check the relay and the condition of the wiring | |
| The glow plug is faulty | Check and replace the spark plug if necessary | |
| Air in the fuel system | Remove air from the fuel system | |
| The fuel pump does not deliver fuel | If fuel is not supplied, loosen the fuel supply pipe to the injector while starting the engine, check the timing belt and fuel supply from the fuel filter | |
| Fuel pipes are not connected correctly | Connect the fuel pipes correctly | |
| Fuel injection timing is incorrectly adjusted | Adjust the fuel injection timing | |
| The injector is faulty | Check and replace the injector if necessary | |
| The mechanical part of the engine is faulty | Check compression and repair engine if necessary | |
| The fuel pump is faulty | Try starting the engine with the new fuel pump and replace the pump if necessary. Check and, if necessary, adjust the engine's idle speed of the crankshaft | |
| Idle speed is incorrect, rough or erratic | The fuel supply hose from the fuel filter to the fuel pump is leaking | Secure the hose securely |
| Air in the fuel system | Remove air from the fuel system | |
| Insufficient fuel supply due to contamination of the fuel filter or fuel return line, leakage from the fuel supply line to the injector, kinking of the line or pinched connections of the lines | Inspect and replace pipes and hoses if necessary or replace the fuel filter | |
| The injector is faulty | Check and replace the injector if necessary | |
| Fuel injection timing is incorrectly adjusted | Adjust the fuel injection timing | |
| The mechanical part of the engine is faulty | Check compression and repair engine if necessary | |
| The fuel pump is faulty | Try starting the engine with the new fuel pump and replace the pump if necessary. Check and, if necessary, adjust the engine's idle speed of the crankshaft | |
| Engine overload when driving in high gear | Maintain correct driving speeds | |
| Smoky exhaust (black, blue or white) | The engine does not warm up to normal operating temperature | Check and, if necessary, replace the cooling system thermostat |
| Inappropriate maximum engine crankshaft speed | Check and replace the fuel pump if necessary | |
| The injector nozzles are faulty | Check and, if necessary, repair or replace fuel injectors | |
| Fuel injection timing is incorrectly adjusted | Adjust the fuel injection timing | |
| The exhaust system capacity is limited | Check the exhaust system for dents | |
| The mechanical part of the engine is faulty | Check compression and repair engine if necessary | |
| The fuel pump is faulty | Try starting the engine with the new fuel pump and replace the pump if necessary. Check and, if necessary, adjust the engine's idle speed of the crankshaft | |
| Reduced engine power, insufficient vehicle acceleration (the speedometer is working properly, the clutch does not slip) | Inappropriate maximum engine crankshaft speed | Check and replace the fuel pump if necessary |
| The air filter is dirty | Clean or replace the air filter | |
| Insufficient fuel supply due to contamination of the fuel filter or fuel return line, leakage from the fuel supply line to the injector, kinking of the line or pinched connections of the lines | Inspect and replace pipes and hoses if necessary or replace the fuel filter | |
| Air in the fuel system | Remove air from the fuel system | |
| The injector nozzles are faulty | Check and, if necessary, repair or replace fuel injectors | |
| Fuel injection timing is incorrectly adjusted | Adjust the fuel injection timing | |
| The mechanical part of the engine is faulty | Check compression and repair engine if necessary | |
| The fuel pump is faulty | Try starting the engine with the new fuel pump and replace the pump if necessary. Check and, if necessary, adjust the engine's idle speed of the crankshaft | |
| Increased fuel consumption | The air filter is dirty | Clean or replace the air filter |
| Fuel leaks | Check and, if necessary, replace or tighten fuel line connections | |
| The capacity of the fuel return pipes is limited | Check the fuel return line for dents and pinches. Replace damaged tubes. If the tube is clogged, blow it out with compressed air, then bleed the air from the fuel system | |
| The injector nozzles are faulty | Check and, if necessary, repair or replace fuel injectors | |
| The mechanical part of the engine is faulty | Check compression and repair engine if necessary | |
| The fuel pump is faulty | Try starting the engine with the new fuel pump and replace the pump if necessary. Check and, if necessary, adjust the engine's idle speed of the crankshaft | |
| The engine does not stop | The starting switch is not working properly | Repair or replace the starting switch |
| Damage to the electrical circuit between the starting switch and the fuel solenoid | Replace the wiring |
Troubleshooting the Engine Starting System
Malfunction | Probable causes | Method of elimination |
| The engine crankshaft does not turn over with the starter | The battery is discharged | Charge or replace the battery |
| Poor connection of wires to battery terminals | Securely fasten the wires to the battery terminals | |
| The lock switch is faulty on cars with automatic transmission | Adjust the position or replace the switch | |
| The fuse link has blown | Replace the fuse link | |
| Starter faulty | Repair the starter | |
| The injector is faulty | Replace the injector | |
| The engine crankshaft is turned slowly by the starter | The battery is not charged enough | Charge the battery |
| Poor connection of wires to battery terminals | Securely fasten the wires to the battery terminals | |
| Starter faulty | Repair the starter | |
| The starter continues to operate after the engine has started | Starter faulty | Repair the starter |
| The ignition switch is faulty | Repair or replace the ignition switch | |
| The starter motor runs at high speed but does not turn the engine crankshaft | Short circuit in an electrical circuit | Restore the electrical circuit |
| Broken gear teeth or faulty starter | Repair the starter | |
| The teeth of the flywheel ring gear are broken | Replace the flywheel ring gear |
Troubleshooting the Fuel Tank and Fuel Lines
Sign | Probable cause | Method of elimination |
| Unstable engine operation due to insufficient fuel supply | The fuel line or fuel supply hose is bent | Replace or repair |
| The fuel supply hose is dirty | Clean or replace | |
| The fuel filter is dirty | Replace the filter | |
| Water in the fuel filter | Replace the fuel filter or clean the fuel tank and fuel lines | |
| Dirty or rusty interior of fuel tank | Clean or replace | |
| Malfunctioning fuel pump | Replace | |
| When the fuel filter indicator light comes on in the instrument cluster | Water has accumulated in the fuel filter | Remove water from the fuel filter as follows: – Loosen the mounting bolt on the fuel filter and lift the fuel filter; – loosen the drain plug on the fuel filter; – when water stops coming out of the fuel filter, tighten the drain plug |