An ignition coil - or spark coil - is a piece of metal coil connected directly to the car's spark plug. It is both a small computer and an electrical coil at the same time. But how does an ignition coil work?
When you turn the key in the ignition, a sensor tells the engine control - the car's computer itself - how many revolutions the engine has. This signals to the ignition coil that it must distribute the ignition signal to the spark plugs. An ignition coil is the electrical device that supplies inductional power to the spark plug and so engages the combustion spark.
There may be an ignition coil for each spark plug or a single ignition coil for all. Sometimes, where multiple coils are connected to each of their respective cylinders, a molded block, including high-tension terminals, surrounds the ignition coils. This is called an ignition coil pack. An ignition coil in each spark plug means they are smaller but can read data from valves and spark plugs more easily. This allows them to adjust the current according to the engine speed.
There are a number of symptoms of ignition coil failure that you should keep an eye out for or that you may have already noticed:
Many people search for "How to test ignition coil". It makes sense to do an ignition coil test if you’re in doubt as to whether something is wrong. Luckily, there are a few ways how to tell if ignition coil is bad. However, we do not recommend that you start an ignition coil test yourself, as the coil is high voltage. It can be very dangerous if you are not experienced with this kind of work.
We therefore strongly recommend that you ask your local mechanic if you have any concerns. If you have a newer, more intelligent car, the mechanic will search for diagnostic trouble codes that reveal which ignition coils are faulty - or if the ignition coil pack is defective. Otherwise, the mechanic will test the actual voltage level in the ignition coil(s) and do an assessment.
Changing the ignition coil is a very variable job - it all depends on the car, the number of ignition coils, etc. However, you can always see where the ignition coils are when you look under the hood.
The mechanic will remove the wires tied to a distributor, which controls the coils. They can pull out the coils - on some cars, however, they have to be unscrewed. New ignition coils can then be installed in the spark plugs and the distributor.
If you need to replace your car's ignition coil(s), ask for quotes on the job at Autobutler's garages. Our customers save 20-40% by comparing quotes!
| Make | Compare and save* | You save on average* | Ratings | |
|---|---|---|---|---|
| Audi | £139 | 25% |
5.0
(6)
6
0
0
0
0
Read the reviews
|
|
| BMW | £139 | 28% |
3.5
(2)
1
0
0
1
0
Read the reviews
|
|
| Citroën | £172 | 23% |
5.0
(1)
1
0
0
0
0
Read the reviews
|
|
| Ford | £152 | 24% |
4.7
(10)
8
1
1
0
0
Read the reviews
|
|
| Mercedes-Benz | £135 | 24% |
4.8
(4)
3
1
0
0
0
Read the reviews
|
|
| Mini | £173 | 30% |
3.7
(3)
2
0
0
0
1
Read the reviews
|
|
| Peugeot | £154 | 25% |
4.5
(8)
7
0
0
0
1
Read the reviews
|
|
| Renault | £183 | 24% |
5.0
(1)
1
0
0
0
0
Read the reviews
|
|
| Vauxhall | £138 | 25% |
5.0
(14)
14
0
0
0
0
Read the reviews
|
|
| Volkswagen | £156 | 26% |
4.8
(8)
7
0
1
0
0
Read the reviews
|
|
| Make | Save on average* | |||
|
Audi
5.0
(6)
6
0
0
0
0
Read the reviews
|
£139 / 25% | |||
|
BMW
3.5
(2)
1
0
0
1
0
Read the reviews
|
£139 / 28% | |||
|
Citroën
5.0
(1)
1
0
0
0
0
Read the reviews
|
£172 / 23% | |||
|
Ford
4.7
(10)
8
1
1
0
0
Read the reviews
|
£152 / 24% | |||
|
Mercedes-Benz
4.8
(4)
3
1
0
0
0
Read the reviews
|
£135 / 24% | |||
|
Mini
3.7
(3)
2
0
0
0
1
Read the reviews
|
£173 / 30% | |||
|
Peugeot
4.5
(8)
7
0
0
0
1
Read the reviews
|
£154 / 25% | |||
|
Renault
5.0
(1)
1
0
0
0
0
Read the reviews
|
£183 / 24% | |||
|
Vauxhall
5.0
(14)
14
0
0
0
0
Read the reviews
|
£138 / 25% | |||
|
Volkswagen
4.8
(8)
7
0
1
0
0
Read the reviews
|
£156 / 26% |
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