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| Home / Car Engines / Toyota Engines / Toyota 1NZ-FE |
Toyota 1NZ-FE Troubleshooting
| Engine difficult to start or won't start |
No gasoline in tank - Fill fuel up.
Low-quality gasoline - Change gasoline.
Air in fuel system - Bleed fuel system.
Spark plug wiring connection is defective - Inspect spark plug wiring connection, change or repair.
Spark plug is faulty - Spark plug need to be replaced.
Defective ignition system - Inspect ignition system and change failed components.
Clogged fuel filter - Install new filter.
Restricted fuel lines - Clean fuel system lines.
Dirty or defective fuel pump - Clean or change fuel pump.
Clogged or defective fuel injectors - Clean or replace fuel injectors.
Low compression - Check and replace worn parts.
| Rough engine running |
Defective ignition - Inspect ignition system and change faulty parts.
Air filter element is clogged - Replace or clean air filter.
Damaged spark plug - Replace spark plug.
Fuel pump is faulty or clogged - Clean or install new fuel pump.
Valve clearance is incorrect - Adjustment procedure required.
Improper ignition timing - Adjust ignition timing as required.
Incorrect low idle setting - Correct idle settings.
| Engine starts and stalls immediately |
Faulty spark plug - Spark plug need to be replaced.
Dirty or faulty fuel injectors - Service or replace fuel injectors.
Damaged ignition coil - Change ignition coil as required.
Broken or loose valve springs - Replace valve springs.
Valves are stuck - Clean the valves.
| Engine is overheated |
Lack of engine oil - Checking oil level and add if necessary.
Engine is overloaded - Reduce load.
Fuel injectors are dirty - Need to clean fuel injectors.
Incorrect ignition timing - Set the ignition timing correctly.
Wrong valve setting - Adjust valves as required.
Clogged radiator fins or leaking radiator cap - Change cap or clean radiator.
Coolant level is low - Add coolant and check the components of cooling system.
Thermostat is faulty - Thermostat need to be replaced.
Water pump is defective - Change water pump as required.
| Engine knocks or noises |
Low octane fuel - Use correct gasoline.
Engine overloaded - Load reducing required.
Engine oil level is insufficient - Check oil level and add oil as required.
Too low idle RPM - Test and adjust.
Fuel pump is damaged or dirty - Check fuel pump and change if required.
Crankshaft or main bearings failure - Change defective components as required.
Valve clearance is not correct - Check and adjust.
Piston rings or cylinder bore are worn - Replace defective components.
| Engine power is too low |
Dirty or damaged fuel injectors - Check fuel injectors and change if required.
Air filter element is plugged - Change or clean air filter.
Fuel pump is dirty or defective - Clean or install new fuel pump.
Ignition failure - Inspect ignition system and change faulty parts.
Blown cylinder head gasket - Install new cylinder head gasket.
Valves are stuck or burned - Service or replace valves.
Damaged cylinder block parts - Replace defective parts.
Oil filter is blocked - Replace or service oil filter.
| High fuel consumption |
Air filter is blocked - Replace or clean air filter.
Fuel injectors are defective or dirty - Clean or change fuel injectors.
Spark plug is loose or faulty - Tighten or replace spark plug.
Bad ignition timing - Set the ignition timing correctly.
Valves are stuck, worn, or burned - Service or replace valves.
Rings, sleeve, or piston are damaged - Replace defective parts.
Valve clearance is incorrect - Adjust to proper valve clearance.
Poor compression - Inspect and replace wear parts.
| Excessive engine oil consumption |
Worn gaskets or seals - Replace defective parts.
Worn valve guides and valve stems - Valves need to be changed.
Piston rings are stuck or worn - Piston rings need to be replaced.
Piston or cylinder liner is scuffed - Check piston and liner, replace as required.
| Engine backfires |
Fuel injectors are dirty - Service or replace fuel injectors.
Fuel lines clogging - Clean fuel system lines.
Incorrect ignition timing - Set the ignition timing correctly.
Incorrect valve setting - Adjust valves correctly.
Air filter is blocked - Clean or replace air filter.
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