Paul Messam, Gleaner writer

A mechanic repairing a car. It is important to pay attention to the mechanical well-being of your vehicles.- File

Do you know your vehicle? Can you immediately detect a problem in your prized machine? Are you able to spot when there is missing, surging and lack of power in your car?, These are important facts that will help you keep your vehicles in tip-top shape.

Hopeton Forrest, an experienced auto mechanic, advises each driver to pay strict attention to the mechanical well-being of his motor vehicle. Surging, according to Forrest, describes an engine that delivers a pronounced variation in powe the accelerator pedal and the throttle are kept steady. To the driver, it seems as if the car is speeding up and slowing down.

spitting sound

Missing occurs under two operating conditions, he says. This is at idle and under way. An engine that misses at idle runs unevenly and feels as if it is skipping. "If the condition is bad enough, the car shakes," confirms Forrest. A missing engine gives a steady pulsating or a jerk that usually becomes more pronounced as load on the engine is increased. The sensation is not normally felt, about 30 mph. Under way and at idle, a missing engine often causes the exhaust to produce a steady spitting sound.

Lack of power does not necessarily mean no power. It means a sluggish action. It defines an engine that is not delivering the power it should be at high speed or when when put under load. According to Forrest, the car does not accelerate to the speed it should, it loses speed going uphill, and it has less-than-normal top speed for the position of the throttle. The factors that cause stalling can also cause missing. Here are some checks to make to track down the real cause:

HIGHLIGHT CHECKS

Check 1: Look for vacuum loss through loose or split vacuum hoses.

Check 2: Ensure that no leak exists.

Check 3: Examine carefully the primary ignition wires at the coil and the distributor. Replace the wires that have cracked insulation, and see that the wires are tightly connected.

Check 4: Disconnect the carburettor air vacuum tube if one exists. Plug the tube opening or the opening in the air cleaner or manifold so vacuum is not lost.

Check 5: Disconnect vacuum hose of the exhaust gas recirculation (EGR) valve. Plug end of the hose so vacuum is retained while the engine is running, make use of insulated pliers to avoid a shock. There should be a drop in the engine revolution per minute (rpm) as each plug is disconnected. If there is a drop in rpm, check the following:

1. Thermostat air cleaner

2. Distributor and distributor points

3. Engine timing and carburettor mixture and idling speed.

4. Positive crankcase ventilation (PCV).

5. Remove the spark plugs; examine for cracks, wear, improper gap, burning or fouling. If missing continues, test each spark plug cable.

Tracking the cause of surging

The cause:

Sensible corrections:

Vacuum leak from carburettor manifold area.

Repair

Defective or loose primary wires at coil and

distributor.

Tighten or replace

Incorrect ignition timing

Make adjustments

Dirty fuel filter

Replace

Defective spark plugs

Service or replace

Weak fuel pump

Replace

Split, leaking or kinked fuel line or hose

Replace

Tracking lack of power

The cause:

Incorrect ignition timing.

Adjust

Malfunctioning automatic choke

Adjust or repair

Dirty air cleaner filter

Replace

Defective spark plugs

Service or repair

Sticking valves

Test compression/repair