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Fitting a new coil

If your car is misfiring or running badly, or has suddenly stopped completely, the most likely source of the problem is the ignition system. Read more

Overhauling a Bosch distributor

Bosch distributors are found on many different cars and are generally very reliable. But after a high mileage you may find that the engine isn't running quite as it should. If the rest of the fuel and ignition system is well tuned but the car doesn't accelerate cleanly, the problem may lie in the distributor advance mechanism. Read more

Troubleshooting the ignition warning light

The ignition warning light, sometimes known as the no-charge light, is one of the most important lights on your dashboard. It warns you when the car's generator is not charging the battery. Read more

Curing running on

Running-on is when the engine continues to turn after you've switched off the ignition because the fuel/air mixture is being ignited by a hot-spot in the combustion chamber. Furthermore, because the mixture is often firing at the wrong point in the cycle, the engine does not run smoothly but jerks and rocks badly on its mountings (and sometimes backfires). The problem can be so bad that the engine runs on for a minute or more if left alone. Read more

Checking the low-tension circuit

The low-tension (LT), or primary-ignition, circuit consists of the battery, ignition switch, breaker, and the primary winding of the coil. Read more

Checking the high-tension circuit

The high-tension (HT) or secondary circuit carries high-voltage electricity. It runs from the secondary winding of the coil through the distributor to the plugs. Any of these can break down and cause ignition failure. Read more

Fitting a condenser

The condenser is a small electrical device connected across the -breaker points in the distributor. Read more

Cleaning and fitting spark plugs

Check and clean sparkplugs every 5,000 miles (8,000 km) and replace them after 10,000 miles (16,000 km). Their condition can tell you about the condition of the engine, and help you to correct faults elsewhere. Read more

Inspecting the ignition system

Inspect the ignition system whenever you make a general under-bonnet check. It takes only a couple of minutes, and guards against a frequent cause of breakdown. Read more

How the ignition system works

The purpose of the ignition system is to generate a very high voltage from the car's 12 volt battery, and to send this to each sparkplug in turn, igniting the fuel-air mixture in the engine's combustion chambers. Read more

How engine timing works

For an engine to work at its best, the fuel/air mixture in each cylinder must fire just as the piston reaches top dead centre (TDC). Read more

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