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| Home / Car Engines / BMW Engines / BMW M42B18 |
BMW M42B18 Troubleshooting
| Engine difficult to start or doesn't start |
Gas tank is empty - Fill fuel up.
Wrong fuel grade - Use correct gasoline grade.
Dirt and debris in fuel system - Remove debris and dirt.
Damaged spark plug wiring connection - Check spark plug wiring connection, repair or change.
Faulty spark plug - Spark plug need to be replaced.
Ignition system is defective - Check ignition system and replace faulty parts.
Dirty fuel filter - Change fuel filter.
Fuel lines are clogged - Fuel lines must be clean.
Dirty or defective fuel pump - Inspect fuel pump and change as required.
Fuel injectors are clogged or faulty - Test fuel injectors and replace if necessary.
Engine has low compression - Check cylinder block and replace defective parts.
| Engine runs roughly |
Ignition system malfunction - Inspect ignition system and change failed components.
Air filter is blocked - Clean or replace air filter.
Damaged spark plug - Spark plug need to be replaced.
Dirty or faulty fuel pump - Clean or change fuel pump.
Improper valve clearance - Adjustment procedure required.
Bad ignition timing - Set the ignition timing correctly.
Low idle speed setting is incorrect - Correct idle adjustment.
| Engine starts but then stalls |
Spark plug is damaged - Change spark plug.
Fuel injectors are dirty or defective - Clean or install new fuel injectors.
Damaged ignition coil - Replace ignition coil as necessary.
Bad or broken valve springs - Install new valve springs.
Valves are stuck - Valves need to be cleaned.
| Engine overheats |
Not enough engine oil - Fill up the engine oil.
Excessive engine load - Reduce engine load.
Clogged fuel injectors - Need to clean fuel injectors.
Wrong ignition timing - Set the ignition timing correctly.
Incorrect valve setting - Adjust valves as required.
Clogged radiator fins or leaking radiator cap - Replace cap or clean radiator.
Insufficient coolant - Fill the cooling system and check components for leaks or other faults.
Thermostat is faulty - Replace thermostat.
Faulty water pump - Water pump need to be replaced.
| Engine noises or knocks |
Stale or low octane fuel - Change gasoline.
Engine is under excessive load - Reduce engine load.
Engine oil level is low - Check oil level and add oil as required.
Incorrect low idle setting - Adjust as required.
Fuel pump is damaged or dirty - Test fuel pump and replace if necessary.
Worn crankshaft or main bearings - Crankshaft or bearings need to be replaced.
Valve clearance is improper - Need to adjust valve clearance.
Damaged piston rings or cylinder bore - Change defective components.
| Engine power is insufficient |
Fuel injectors are clogged or faulty - Check fuel injectors and replace if necessary.
Air filter is dirty - Service or change air filter.
Fuel pump is dirty or defective - Check fuel pump and change if required.
Defective ignition - Inspect ignition system and change failed components.
Cylinder head gasket is worn - Install new cylinder head gasket.
Stuck or burned valves - Change or clean valves.
Faulty cylinder block parts - Replace defective components.
Oil filter is dirty - Service or replace oil filter.
| Engine using too much gasoline |
Air filter is dirty - Replace or service air filter.
Dirty or defective fuel injectors - Inspect fuel injectors and change as required.
Spark plug is faulty or loose - Replace or tighten spark plug.
Wrong ignition timing - Adjust ignition timing as required.
Stuck, worn, or burned valves - Service or replace valves.
Worn sleeve, rings, or piston - Change defective components.
Valve clearance is improper - Check and adjust.
Poor engine compression - Check cylinder block and replace damaged components.
| Engine consuming too much oil |
Worn gaskets or seals - Worn parts need to be replaced.
Damaged valve guides or valve stems - Change the valves.
Piston rings are defective or worn - Piston rings replacement required.
Piston or cylinder liner is damaged - Check piston and liner, replace as required.
| Engine backfires |
Fuel injectors are dirty - Test fuel injectors and clean if necessary.
Clogged fuel lines - Clean fuel lines.
Ignition timing is wrong - Adjust ignition timing correctly.
Wrong valve setting - Adjust valves correctly.
Air filter is dirty - Service or change air filter.
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