Tue | Sep 28, 2021

Click! Click! ... Engine choke, cough, silence … . Possible causes

Published:Sunday | July 11, 2021 | 12:06 AMPaul Glenroy Messam -

The basis of a well-maintained motor car is a well-tuned engine. “Without an engine that operates at full efficiency, a vehicle is a hazard on the highway and a source of stress for the driver,” says Kurt Harding, auto mechanic.

“The driver of a car with an untuned engine is not safe on the road,” he emphasises.

According to Harding, the engine of the car is a converter of energy. It converts the energy of heat into the energy of motion. This action turns the crankshaft to which each piston is attached by a connecting rod. Each piston, in turn, is pulled to the bottom of the cylinder. As the piston is drawn down, a vacuum is created, and the intake valve opens, allowing a mixture of air and gasolene into the cylinder.

Let us examine the cause when the engine rough idles; engine turns over but will not start (engine cold); engine turns over but will not start ( engine hot).

Engine rough idles:

1. Ignition pistons worn or not properly adjusted.

2. Excessive carbon build-up in combustion chambers, resulting in higher-than-normal compression ratio.

3. Engine idling too slowly.

4. Carburettor idle-adjustment screws unbalanced.

5. Disconnected vacuum hose.

6. A leak at the intake manifold.

7. A sticking positive crankcase ventilation valve.

8. Faulty modulator valve in automatic transmission.

9. Spark plug worn or not properly gapped.

The engine turns over but will not start (engine cold):

1. When cold, it may help to depress the gas pedal at least once. This is one of the major causes of starting failure in cold weather. A sticking or improperly adjusted automatic choke is another likely cause.

2. Frequently, in damp weather, moisture on the ignition components will prevent the vitally important high voltage from reaching the spark plugs.

3. Engine oil too heavy; accelerator linkage disconnected or jammed.

4. Poor compression due to worn valves or piston rings.

5. A poorly tuned engine.

6. Malfunctioning carburetor and an empty gas tank.

The engine turns over but will not start (engine hot):

1. A common cause of this type of failure is when the engine is flooded with an excessive quantity of gasolene.

2. The best thing to do is wait a few minutes then push the gas pedal just once, all the way down to the floor.

3. Remember, pumping the gas pedal up and down several times only accentuates the flooding condition.

4. So with the gas pedal held down to the floor, engage the starter motor and turn over the engine several times. Usually, the engine should start.

The engine will not accelerate after normal warm-up period:

1. Late ignition or valve timing.

2. Inadequate fuel supply to carburettor.

3. Automatic transmission not shifting down.

4. Fuel mixture too lean.

5. Defective accelerator linkage.

6. Air leak at intake manifold.

7. Restricted exhaust system.

8. Heat riser valve stuck open.

9. Worn piston rings.

10. Improperly adjusted spark plugs or ignition points.