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BMW M50B20TU Troubleshooting

Engine doesn't start or starts hard

Empty gas tank - Add fuel.
Low-quality gasoline - Use quality fuel.
Dirty fuel system - Check and clean.
Spark plug wiring connection is defective - Check spark plug wiring connection, repair or change.
Spark plug is defective - Install new spark plug.
Ignition system is defective - Check ignition and replace faulty components.
Fuel filter is dirty - Install new filter.
Dirty fuel lines - Fuel lines must be clean.
Fuel pump is dirty or defective - Clean or change fuel pump.
Dirty or faulty fuel injectors - Check fuel injectors and change if required.
Bad engine compression - Inspect cylinder block and replace worn components.

Unstable engine running

Ignition failure - Check ignition system and replace faulty parts.
Dirty air filter element - Replace or clean air filter.
Damaged spark plug - Change spark plug.
Dirty or faulty fuel pump - Check fuel pump and replace if necessary.
Valve clearance is not correct - Adjust to proper valve clearance.
Wrong ignition timing - Ignition timing needs to be set properly.
Low idle speed setting is incorrect - Correct idle settings.

Engine stops after starting

Damaged spark plug - Spark plug need to be replaced.
Dirty or damaged fuel injectors - Test fuel injectors and replace if necessary.
Ignition coil is not working - Ignition coil must be replaced.
Broken or loose valve springs - Change valve springs.
Stuck valves - Valves need to be cleaned.

Engine is overheated

Insufficient engine oil - Fill up the engine oil.
Engine overloaded - Load reducing is recommended.
Fuel injectors are clogged - Service or replace fuel injectors.
Ignition timing is wrong - Adjust ignition timing as required.
Improper valve setting - Adjust valves as required.
Dirty radiator core or faulty radiator cap - Clean radiator or replace cap.
Insufficient coolant fluid - Add coolant and check the components of cooling system.
Thermostat is faulty - Change thermostat as required.
Water pump malfunction - Replace water pump.

Engine knocks or noises

Stale or low octane fuel - Change fuel.
Engine overload - Load reducing required.
Engine oil level is low - Need to add engine oil.
Low idle speed setting is not correct - Adjust the low idle speed.
Fuel pump is damaged or dirty - Service or replace fuel pump.
Worn main bearings or crankshaft - Worn parts replacement required.
Valve clearance is improper - Need to adjust valve clearance.
Piston rings or cylinder bore are worn - Change faulty components.

Engine loses power

Fuel injectors are faulty or clogged - Clean or install new fuel injectors.
Clogged air filter - Change or service air filter.
Dirty or damaged fuel pump - Clean or install new fuel pump.
Defective ignition system - Inspect ignition system and change faulty parts.
Damaged cylinder-head gasket - Change cylinder head gasket.
Burned or stuck valves - Clean or change valves.
Worn cylinder block parts - Change defective parts.
Oil filter element is clogged - Change or clean oil filter.

High fuel consumption

Dirty air filter element - Replace or clean air filter.
Clogged or damaged fuel injectors - Clean or change fuel injectors.
Spark plug is defective or loose - Replace or tighten spark plug.
Ignition timing is improper - Set the ignition timing properly.
Valves are worn, burned or stuck - Change or service valves.
Rings, sleeve, or piston are damaged - Change faulty parts.
Improper valve clearance - Adjust valve clearance.
Bad engine compression - Inspect cylinder block and replace worn components.

High oil consumption

Gaskets or seals are excessively worn - Install new components.
Damaged valve stems or valve guides - Valves need to be changed.
Seized or wear piston rings - Have piston rings replaced.
Worn cylinder liner or piston - Check liner and piston, replace as required.

Engine backfires

Fuel injectors are clogged - Clean or change fuel injectors.
Clogged fuel lines - Fuel lines must be clean.
Ignition timing is wrong - Set the ignition timing correctly.
Incorrect valve setting - Adjust valves as required.
Air filter is dirty - Service or change air filter.