19 types of engine troubles and their possible causes are discussed in this article. The engine is the most important component in the vehicle. This needs extra care to make it a trouble-free ride. So, then read the engine troubles and their possible causes to decide on the repair.

Engine Troubles and Their Possible Causes

Diagnosing faults is finding faults by signs, sounds, and testing. For this purpose, the inspector or mechanic should be skilled in diagnosing the faults. By knowing and understanding the construction of the part and its operation, skills can be gained.

Wear causes a large number of faults in a vehicle generally. By the feel of the movement of the parts, a skilled mechanic can tell if the wear that occurred is within the serviceable running limit or not. Feeling the fit of vehicle parts can be learned by experience.

The mechanic should be skilled in distinguishing the nose created due to breakage or wear and the noise created by certain parts when in motion. Different types of tread patterns have differing intensities of humanity. Compared to a carbon thrust bearing or pad, the noise produced by a clutch-release bearing of a ball race pattern produces much more noise.

Similarly knocking off a petrol engine should be indicative of certain faults. The presence of carbon, burnt valves, high temperature, low-grade fuel, too much ignition advance, or failure to change gear usually causes knocking in a petrol engine.

The mechanic should be able to relate the noise speed to the engine speed, the road, or a load that can be varied by changing gears. He must be able to distinguish if it occurs equally on left and right-hand turns if it increases or decreases when any of the cylinders is cut out or if it occurs only when the vehicle is stationary or only when it is in motion.

Here are given the various engine troubles and their causes. The remedies for these troubles are not given because they are self-understood according to the causes. Some of the major troubles of scooters, cars, and tractors are also elaborated with their causes.

Read more- How to Design a Fuel-Efficient Engine?

1. The engine does not turn over when starting is attempted

• Discharged battery
• Open starting circuit
• Jammed self-starter
• Jammed cranking drive
• Jammed engine

2. The engine turns over slowly but does not start

• Discharged battery
• Defective cranking motor
• Bad connection in starting circuit
• Undersized battery cables

3. The engine turns over at normal speed but does not start

• Defective ignition system
• Defective or chocking fuel system
• Air leakage in the intake manifold or carburetor
• defective engine

Read more- How Crankshaft and Camshaft Position Sensor Increase the Engine Efficiency?

4. The engine runs but misses one cylinder

• Defective spark plug
• Defective distributor lead or cap
• Stuck valve
• Defective pistons or rings
• Defective head gasket

5. The engine runs but misses different cylinders

• Defective ignition
• Defective fuel system
• Loss of compression
• Defective valve action
• Defective rings
• Overhead engine
• Sticking manifold heat control valve
• Clogged exhaust

6. The engine lacks power, acceleration, or high-speed performance in hot or cold

• Defective ignition
• Defective fuel system
• Clogged exhaust
• The throttle valve not opening fully
• Loss of compression
• Excessive carbon in the engine
• Defective valve action
• Excessive rolling resistance from low-type pressure, dragging brakes, wheel misalignment, etc.
• Heavy oil
• Wrong or bad fuel

Read more- What is Detonation in an Engine?

7. The engine lacks power, acceleration, or high-speed performance at hot-only

• Engine overheats
• Defective choke
• Sticking manifold-heat control valve
• Vapor lock

8. Engine lacks power, acceleration, or high-speed performance, cold-only

• Stuck automatic choke
• Stuck manifold heat control valve
• Stuck cooling system thermostat
• Stuck engine valves

9. Engine overheats

• Lack of water
• Late ignition timing
• Loose or broken fan belt
• Defective thermostat
• Clogged water jackets
• Defective radiator hose
• Defective water pump
• Insufficient engine oil
• High altitude, hot climate operation
• Late valve timing

10. Rough Idle

• Incorrect carburetor idle adjustment
• Malfunctioning crankcase ventilator valve on closed crankcase ventilating system
• Also, causes listed under 6,7, and 8

11. Engine stalls cold or as it warms up

• Closed choke valve
• Fuel not getting to or through the carburetor
• The manifold heat control valve stuck
• Engine overheats
• Too low setting of idling speed

Read more- Overcooling of Engine | Problems Due to Overcooling the Engine.

12. Engine stalls after idling or speed driving slow

• Defective fuel pump
• Overheating
• High carburetor float level
• Incorrect idling adjustment

13. Engine stalls after high-speed driving

• Vapor lock
• defective carburetor venting or idling compensator valve
• Engine overheats

14. Engine backfires

• Ignition timing off
• The spark plug of the wrong heat range
• Excessive rich or lean mixture
• Overheating of engine
• Carbon in engine
• Valves hot or sticking
• Cracked distributor cap

15. Smoky Exhaust

• Excessive oil consumption
• Excessive rich mixture

16. Excessive oil consumption

• External leaks
• Burning oil in a combustion chamber

17. Low oil pressure

• Worn engine bearing
• Engine overheating
• Oil dilution or foaming
• Defective lubrication system

Read more- The Importance of Thermostat Valve | Keep Your Engine Cool and Smooth.

18. Excessive fuel consumption

• Nervous driver
• High speed
• Short run operation
• Excessive fuel pump pressure or pump leakage
• Choke partly closed after warm-up
• Clogged air cleaner
• High carburetor float level
• Stuck or dirty float needle valve
• Worn carburetor jet
• Stuck metering rod or full-power piston
• Idle too rich or too fast
• Stuck accelerator pump check valve
• Carburetor leaks
• Faulty ignition
• Loss of engine compression
• Defective valve action
• Clutch slippage
• Excessive rolling resistance from low tire pressure, dragging brakes, wheel misalignment, etc.

19. The engine is noisy

• Valve and tappet noise
• Spark knock due to low octane fuel, and carbon advance ignition timing
• Worn connecting rod bearing or crank pin, misaligned rod, lack of oil
• Worn or loose piston pin or lack of oil
• Piston slap due to worn pistons, walls, collapsed piston skirts, excessive clearance lack of oil
• Regular noise, worn main bearings, irregular, worn end thrust bearings.

Conclusion on Engine Troubles and Their Possible Causes

The engine is the most important component in a vehicle. So, this engine needs to be maintained properly to have a clean and effortless drive. Small engine troubles can also cause big issues if this is not treated properly. A skilled technician only can repair the engine problems. Do not use your hands to make the engine feel good, this will cause problems to your wallet.