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| Home / Car Engines / Toyota Engines / Toyota 1AZ-FE |
Toyota 1AZ-FE Troubleshooting
| Engine difficult to start or doesn't start |
Fuel tank is empty - Fill it up.
Wrong grade of gasoline - Change gasoline.
Air trapped in fuel system - Bleed air.
Spark plug wiring connection is defective - Inspect spark plug wiring connection, change or repair.
Spark plug is faulty - Spark plug need to be replaced.
Ignition system failure - Inspect ignition system and change faulty parts.
Clogged fuel filter - Change fuel filter.
Dirty fuel lines - Service fuel lines.
Fuel pump is clogged or faulty - Clean or change fuel pump.
Dirty or defective fuel injectors - Clean or change fuel injectors.
Low compression - Check and replace worn parts.
| Engine runs roughly |
Ignition system problems - Test ignition and replace failed parts.
Dirty air filter element - Replace or service air filter.
Faulty spark plug - Change spark plug.
Fuel pump is faulty or clogged - Test fuel pump and change if necessary.
Valve clearance is wrong - Check and adjust.
Ignition timing is improper - Adjust ignition timing correctly.
Low idle speed setting is incorrect - Correct the settings.
| Engine starts and stops |
Faulty spark plug - Change spark plug as required.
Dirty or defective fuel injectors - Clean or install new fuel injectors.
Damaged ignition coil - Ignition coil should be replaced.
Valve springs are weak or broken - Replace valve springs.
Valves are stuck - Service the valves.
| Engine overheated |
Low engine oil level - Need to add engine oil.
Engine is running overloaded - Load reducing required.
Fuel injectors are dirty - Need to clean fuel injectors.
Ignition timing is incorrect - Set the ignition timing correctly.
Wrong valve setting - Set the valves properly.
Radiator fins are dirty or radiator cap is defective - Clean radiator or change cap.
Insufficient coolant fluid - Refill to the correct level and inspect system for leaks.
Thermostat is defective - Change thermostat as required.
Water pump malfunction - Change water pump as required.
| Engine knocks or noises |
Stale fuel - Use proper gasoline.
Engine overloaded - Reduce load.
Engine oil level low - Check oil level and add oil as required.
Incorrect low idle setting - Adjust idling as required.
Dirty or damaged fuel pump - Clean or replace fuel pump.
Worn crankshaft or main bearings - Repair or replace defective parts.
Valve clearance is wrong - Need to adjust valve clearance.
Piston rings or cylinder bore are worn - Change defective components.
| Engine power loss |
Dirty or faulty fuel injectors - Clean or change fuel injectors.
Dirty air filter element - Change or clean air filter.
Fuel pump is clogged or faulty - Test fuel pump and change if necessary.
Ignition failure - Check ignition and replace faulty components.
Cylinder head gasket is damaged - Install new head gasket.
Valves are burned or stuck - Service or change valves.
Damaged cylinder block parts - Replace defective components.
Oil filter is dirty - Replace or service oil filter.
| Excessive fuel consumption |
Air filter element is plugged - Clean or replace air filter.
Fuel injectors are faulty or clogged - Clean or install new fuel injectors.
Loose or faulty spark plug - Change or re-tighten spark plug.
Bad ignition timing - Ignition timing needs to be set properly.
Worn, stuck, or burned valves - Change or clean valves.
Worn piston, rings, or sleeve - Replace defective parts.
Valve clearance is incorrect - Need to adjust valve clearance.
Low compression - Check and replace worn parts.
| Engine consuming too much oil |
Seals or gaskets are wearing excessively - Worn parts need to be replaced.
Worn valve stems and valve guides - Replace the valves.
Worn or broken piston rings - Piston rings replacement required.
Scored piston or cylinder liner - Inspect liner and piston, change as necessary.
| Engine backfires |
Dirty fuel injectors - Clean or replace fuel injectors.
Clogged fuel lines - Clean fuel lines.
Improper ignition timing - Ignition timing needs to be adjusted correctly.
Improper valve setting - Valves needs to be set correctly.
Air filter is blocked - Service or replace air filter.
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