Troubleshooting the fuel system
sign | Probable Cause | Elimination Method |
Engine won't start | The crankshaft of the engine is turned by a starter slowly | Repair the engine starting system or charge the battery so that the starter cranks the engine at a frequency of at least 150 min-1 |
There is no voltage in the power bus of the glow plugs | If the test lamp does not show voltage when the ignition key is turned to the «ON», check the relay and the condition of the wiring | |
Faulty glow plug | Check and, if necessary, replace the spark plug | |
Air in the fuel system | Bleed the air from the fuel system | |
Fuel pump does not supply fuel | If fuel is not supplied, while starting the engine, loosen the fastening of the fuel supply pipe to the injector, check the toothed belt and the fuel supply from the fuel filter | |
Fuel lines not connected correctly | Connect the fuel lines correctly | |
Incorrectly adjusted fuel injection timing | Adjust the fuel injection timing | |
Faulty injector | Check and, if necessary, replace the nozzle | |
Faulty mechanical part of the engine | Check compression and, if necessary, repair the engine | |
Faulty fuel pump | Try starting the engine with a new fuel pump and replace the pump if necessary. Check and, if necessary, adjust the engine idle speed | |
Idle speed incorrect, rough or erratic | Leaky fuel supply hose from the fuel filter to the fuel pump | Fasten the hose securely |
Air in the fuel system | Bleed the air from the fuel system | |
Insufficient fuel supply due to dirty fuel filter or fuel return pipe, leakage from the fuel supply pipe to the injector, a kink in the pipe, or pinched pipe connections | Inspect and, if necessary, replace pipes and hoses or replace the fuel filter | |
Faulty injector | Check and, if necessary, replace the nozzle | |
Incorrectly adjusted fuel injection timing | Adjust the fuel injection timing | |
Faulty mechanical part of the engine | Check compression and, if necessary, repair the engine | |
Faulty fuel pump | Try starting the engine with a new fuel pump and replace the pump if necessary. Check and, if necessary, adjust the engine idle speed | |
Engine overload when driving in high gear | Maintain the correct driving speeds | |
smoky exhaust (black, blue or white) | Engine does not warm up to normal operating temperature | Check and, if necessary, replace the thermostat of the cooling system |
Incorrect maximum engine speed | Check and, if necessary, replace the fuel pump | |
Faulty injector nozzles | Check and, if necessary, repair or replace the fuel injectors | |
Incorrectly adjusted fuel injection timing | Adjust the fuel injection timing | |
The capacity of the exhaust system is limited | Check the exhaust system for dents | |
Faulty mechanical part of the engine | Check compression and, if necessary, repair the engine | |
Faulty fuel pump | Try starting the engine with a new fuel pump and replace the pump if necessary. Check and, if necessary, adjust the engine idle speed | |
Reduced engine power, insufficient vehicle acceleration (speedometer is good, clutch is not slipping) | Incorrect maximum engine speed | Check and, if necessary, replace the fuel pump |
Air filter dirty | Clean or replace the air filter | |
Insufficient fuel supply due to dirty fuel filter or fuel return pipe, leakage from the fuel supply pipe to the injector, a kink in the pipe, or pinched pipe connections | Inspect and, if necessary, replace pipes and hoses or replace the fuel filter | |
Air in the fuel system | Bleed the air from the fuel system | |
Faulty injector nozzles | Check and, if necessary, repair or replace the fuel injectors | |
Incorrectly adjusted fuel injection timing | Adjust the fuel injection timing | |
Faulty mechanical part of the engine | Check compression and, if necessary, repair the engine | |
Faulty fuel pump | Try starting the engine with a new fuel pump and replace the pump if necessary. Check and, if necessary, adjust the engine idle speed | |
Increased fuel consumption | Air filter dirty | Clean or replace the air filter |
Fuel leaks | Check and, if necessary, replace or tighten fuel pipe connections | |
Limited capacity of fuel return pipes | Check the fuel return pipe for dents or pinches. Replace damaged tubes. If the tube is clogged, blow it out with compressed air, then bleed the air from the fuel system | |
Faulty injector nozzles | Check and, if necessary, repair or replace the fuel injectors | |
Faulty mechanical part of the engine | Check compression and, if necessary, repair the engine | |
Faulty fuel pump | Try starting the engine with a new fuel pump and replace the pump if necessary. Check and, if necessary, adjust the engine idle speed | |
Engine won't stop | Start switch malfunctioning | Repair or replace the start switch |
Damage to the electrical circuit between the start switch and the fuel solenoid | Replace wiring |
Troubleshooting the engine start system
Malfunction | Likely Causes | Elimination Method |
The crankshaft of the engine is not turned by a starter | Discharged battery | Charge or replace the battery |
Unreliable connection of wires to the battery terminals | Attach the wires securely to the battery terminals | |
Faulty lock switch on vehicles with automatic transmission | Adjust position or replace switch | |
Fusible link burned out | Replace fusible link | |
Faulty starter | Repair starter | |
Faulty injector | Replace nozzle | |
The crankshaft of the engine is turned by a starter slowly | Insufficiently charged battery | Charge your battery |
Unreliable connection of wires to the battery terminals | Attach the wires securely to the battery terminals | |
Faulty starter | Repair starter | |
Starter continues to run after engine starts | Faulty starter | Repair starter |
Faulty ignition switch | Repair or replace the ignition switch | |
The starter operates at a high speed, but does not turn the engine crankshaft | Short circuit in the electrical circuit | Repair the electrical circuit |
Broken gear teeth or defective starter | Repair starter | |
Broken flywheel teeth | Replace flywheel ring gear |
Troubleshooting the fuel tank and fuel lines
sign | Probable Cause | Elimination Method |
Unstable operation of the engine due to insufficient fuel supply | Bent fuel line or fuel hose | Replace or repair |
Fuel hose dirty | Clean or replace | |
Fuel filter dirty | Replace filter | |
Water in the fuel filter | Replace fuel filter or clean fuel tank and fuel lines | |
Dirty or rusted inside of the fuel tank | Clean or replace | |
Malfunctioning fuel pump | Replace | |
When the fuel filter warning light comes on in the instrument cluster | Water has accumulated in the fuel filter | Remove water from the fuel filter as follows: – Turn away an assembly 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 |