Car Engine Troubleshooting

Engine Troubleshooting

1. Car not starting

Starter will not run

Causes

1. The main fuse is blown off.
2. Contact is not closing in the main switch or this switch is open circuited.
3. Run down battery.
4. Defective starting relay.
5. The loose terminal connection on the battery.
6. Defective brushes in the starter.

Remedies:-

1.Replace the blown off fuse

The steps to replace blown off fuse are:-

1. Secure the car

Switch off the ignition. Apply the parking brake(hand brakes). In a manual car shift into first gear. In automatic gear shift, the gear into Parking position Fuses have different amperage ratings, each rating is indicated by a different color.

2. Locate the fuse box.

Usually, the fuse box is found under the bonnet(hood). If you have trouble finding the fuse box consult the car manual. Remove the cover to access the fuse panel.

3. Check the fuse diagram.

Observing the diagram you can understand which fuse corresponds to which electrical component.

4. Remove the fuse.

Pull out the fuse observe it. Determine if the fuse is blown. It can be visually inspected by observing if the metal link. If it is separated the fuse is blown and needed to be replaced. If not proceed to next CAUSE.

5. Replace the fuse.

If the fuse has melted replace it with the same rating and with same color code. Slide it down the same slot and ensure it is fitted well A loose connection might not solve the problem.

6. Check

Switch on the ignition. If the engine starts then congrats. If the fuse blows immediately again then get it checked by a mechanic.

1. Loose terminal connection on the battery.

Open the hood and visually inspect the connecting wires to the battery. If it is dirty, clean the terminals and retighten using a wrench of the right size.

3. Run Down Battery

Checking the voltage of battery:-

Step 1:- Take a multimeter.
Plug the black probe to the COM and red probe to mAVQ. Set the multimeter to "20V" DC.
(To measure DC voltage set the regulator to V with a straight line.)

Step 2:- Attach the probes to the correct terminals.
Identify the positive terminal of the battery and connect it to the red probe(mAVQ), and the negative terminal to the black probe(COM).

(Even if you mismatch the wires there would be no problem just the voltage reading would be in negative.)

Step 3:- Observe the readings on the multimeter.
If the reading is more than 12V like 12.5V or 12.8V then the battery is ok, Otherwise, you need to charge it.

Charging the car battery:-

Step:-1 Ensure the engine is off.

Step:- 2 Identify Negative Terminals.
It is covered with a black color-coded cap and minus sign is marked on it.

Step:- 3 Identify Positive Terminals.
It is marked as a plus sign on the top of the battery and this terminal is usually red color coded.

Step:-4 Ensure the charger is off.

Step:-4 Connect the black clamp to the Negative Terminals.
Ensure the terminals are clear, if not clear them with a sandpaper and properly connect the charger clamp to the negative terminal of the car battery.

Step:- 5 Connect the red clamp to the Positive Terminals.


Step:-6 Charge the battery.

Step:-7 Check the alternator of the car is ok or not.

No Sparking

Causes

1. Defective spark plug.
2. Short circuit(grounded) fault in high tension cords.
3. Cracked rotor or cap in distributor.
4. Burnt Breaker contact points.
5. Breaker contact point out of adjustment.
6. Defective condenser.
7. Contact is not closing positively in the main switch or this switch is open circuited.
8. Loose or blown fuse.
9. Ignition timing is out of adjustment.
10. Defective ignition coil.

Remedies

1. Defective spark plug.

Symptoms:-

• Rough Idling of the car.
• Engine misfiring.
• High fuel consumption.
• Lacking acceleration.

Visual Inspection:-

1. Rust - If the bottom or tip or the hexagonal part of the spark plug is rusty.
2. Ceramic Insulation - Check if it is cracked on the body and near the tip as well.
3. Ground Electrode - Check if there are deposits on the ground electrode or it is eroding.
4. Centre Electrode - Check if it is eroding.
5. Gap - Check if the gap between the two electrodes. The appropriate gap is specified on the owners manual or inside the hood on a sticker near the plugs. Checking can be done by any gaping tool such as feeler gauge or wire gaping tool.

Replace spark plug:-

1. Open the hood identify the spark plugs boots.
2. Clean the engine, if there is debris we don't want it to go down in the engine.
3. Use the nose ring pliers to grab the boots and remove them.
4. Clean the "spark plug well".
5. Use a spark plug socket and attach it to an extension if needed then reach down to the spark plug.
6. Use a wrench on the extension to break it loose, then it can be removed by hand only revolving the extension anticlockwise.
7. Check the type of spark plugs being used, and use the exact same type of spark plug to replace the previous one. Also, match their heights and seats, if they are not the same then it can be a misfit for the engine.
8. Check for any damage or gaping for the new ones.
9. Slide the new spark plug in the socket with the extension and hand tighten it to the limit you can. Do not cross thread while tightening it can be felt if any resistance is offered during the process, then back out and tighten again. 
10. Then take the torque wrench and just tight a little more. We don't want it to be too loose so that it is blown out of the engine, or too tight as it would damage the thread.
11. Now push the spark plug boot with the wire all the way down to the spark plug until you hear a click. And that's it.

3. Cracked rotor or cap in the distributor

1. Locate the distributor and remove the cap by removing the fasteners and carefully place the cap aside.
2. Now the rotor would be visible, remove it by hand only. Note its position.
3. Rotate the engine by hand using the appropriate tool on the engine pulley until the points are at the widest opening this is where the heel of the rubbing block of the contact breaker point rides on the cams of the distributor shaft and opens the point as it rotates and clips the
4. Remove the contact breaker points.
5. Unclip the small electrical leads from the ignition coil and capacitor at the back of the point. There are various methods of fixing things so this shorter follooow the instructions in the manual to remove the locating screw from the contact breaker point baseplate then remove the points from the base of the distributor.
6. Inspect the contact breaker points for their condition. Small indications of pitting are quite normal. However, the transfer of more than one millimeter of tungsten material from one side of the points to the other indicates the capacitor may also need changing.
7. Remove the distributor baseplate and check to see that the weight can.be moved on their locating point freely and that the restraining spring is in place and in good order if necessary apply a small amount of the manufactures id specified lubricant.
8. Refit the distributor base plate in its correct location and ensure that the capacitor is located on the base plate is secure.
9. Check vacuum advance unit.
10. Vacuum loads sensitive advance and retards units can be checked by attaching a vacuum source to the end of the unit and watching to see if the base plate moves in relation to its reference points when the vacuum source is moved the base plate should move back to its static position
11. After clean a new points to remove all signs of protective coating locate the new contact breaker point. Locate the new contact breaker point on the baseplate and replace the locating screw leaving it loose enough to allow the points to be moved in relation to the base plate refit the electrical connection from the ignition coil and the capacitor adjust the points by locating the heel of the rubbing block of the contact breaker points so it writes on the cam of the distributor sharp using a feeler gauge of the correct manufacture's specification gently adjust the points with a screwdriver until the points gap is in accordance with specification then tighten the locating screw and recheck the gap setting replace the rotor and the distributor cap and start the vehicle  one the components have been reassembled

Faulty intake or exhaust systems

 1. Car suddenly stops

Causes

1. No fuel in the tank.
2. Loose battery terminal.
3. Fuel Filter blocked.
4. No Spark.
5. Fuel not reaching in the carburettor.
6. No coolant or water pump failure.
7. Radiator hose burst.
8. Thermostat stuck in closed position.
9. Excessive overheating.
10. Carburettor jet blocked.
11. Fuel pump failure.
12. Broken fan belt.
13. Sudden failure of contact breaker points, coil or condenser.
14. Contact breaker points joined or welded together or no gap.
15. Water splashed into the ignition system.
16. Dynamo not charging.5

1. The engine does not run when starting is attempted.

Causes

1. Discharged battery.
2. Open starting.
3. Jammed Bendix drive.
4. Jammed cranking drive.
5. Jammed engine.

Remedy

1. For discharged battery

2. Engine turns over slowly but does not start.

1. Discharged battery
2. Defective cranking motor.
3. Bad connection in the starting circuit.
4. Undersized battery cables.

3. Engine turns overs at normal speed but does not start.

1. Defective ignition system.
2. Defective or over chocking fuel system.
3. Air leakage in the intake manifold or carburetor.

4. Engine runs but misses one cylinder.

1. Defective spark plug.
2. Defective distributor lead or cap.
3. Stuck valve.
4. Defective piston or rings.
5. Defective head gasket.

5. Engine runs but misses different cylinders.

1. Defective ignitions.
2. Defective fuel system.
3. Loss of compression.
4. Defective valve action.
5. Defective rings.
6. Overheated engine.
7. Sticking manifold heat control valve.
8. Clogged exhaust.

6. Engine lacks power acceleration or high-speed performance at hot or cold.

1. Defective ignition
2. Defective fuel system.
3. Clogged Exhaust.
4. Throttle valve not opening fully.
5. Loss of compression.
6. Excessive carbon in the engine.
7. Defective valve action.
8. Excessive rolling resistance from low-type pressure, dragging brakes, wheels alignment.
9. Heavy Oil.
10. Wrong or bad fuel.

7. Engine Overheats

1. Lack of water
2. Late Ignition Timing
3. Loose or broken fan belt
4. Defective thermostat.
5. Clogged Water Jackets.
6. Defective radiator hose.
7. Defective water pump.
8. Insufficient engine oil.
9. High altitude hot climate operation
10. late valve timing

10. Rough Idle

1. Incorrect carburetor idle adjustment.
2. Malfunctioning crankcase ventilator valve on the closed crankcase ventilating system.

11. Engine stalls cold or as it warms up

1. Closed choke valve.
2. Fuel not getting through to or through the carburettor.
3. Manifold heat control valve stuck.
4. Engine overheats.

12. Engine stalls cold or as it warms up.

1. Defective fuel pump.
2. Overheating
3. High Carburettor float level.
4. Incorrect idling adjustment.

13. Engine stalls after high-speed driving.

1. Vapour lock.
2. Defective carburettor venting or idle compensator venting or idle compensator valve.
3. Engine overheats.

14. Engine backfires

1. Ignition timing off.
2. The spark plug of wrong heat range.
3. Excessive rich or lean mixture.
4. Overheating of the engine.
5. Carbon in the engine.
6. Valves hot or sticking.
7. Cracked distributor cap.

15. Smoky Exhaust

A. Black Smoke

1. Choke in operation
2. Spark plug malfunction.
3. Clogged air filter
4. Punctured or incorrectly set carburettor float.
5. Worn out wrong size jets.
6. Needle valve stuck open.
7. Ignition system erratic.
8. Incorrect ignition timing.
9. Worn out, stuck or broken piston rings.

B. Blue Smoke

1. Excessive petrol mixture ratio.
2. Excessive oil in clutch chamber.
3. Crankcase oil seals are worn out or damaged
4. Worn out, stuck or broken piston rings.
5. Worn out cylinder bore.

16.Excessive oil consumption.

1. External leaks.
2. Burning oil in the combustion chamber.

17. Low oil pressure.

1. Worn Engine bearing.
2. Engine overheating.
3. Oil dilution and foaming.
4. Defective lubrication system.

18. Excessive fuel consumption

1. High Speed.
2. Short Run operation.
3. Excessive fuel pump pressure or pump leakage.
4. Choke partly closed after warm up.
5. Clogged air cleaner.
6. High Carburettor float level.
7. Stuck or dirty float needle valve.
8. Worn carburettor jet.
9. Stuck metering rod or full power piston.
10. Idle to rich or too fast.
11. Stuck accelerator pump check valve.
12. Carburettor leaks.
13. Faulty ignition.
14. Loss of ignition compression.
15. Defective valve action.
16. Clutch slippage.
17. Excessive rolling resistance from low tyre pressure, dragging brakes, wheel misalignment, etc.

19. The engine is noisy.