# How much voltage is in a spark plug wire?

## How much voltage is in a spark plug wire?

Spark plug wires deliver thousands of volts – up to 45.000V, depending on the application – to the spark plugs. To do this successfully, they need to be covered in thick insulation to prevent high voltages jumping off the wire before it reaches the spark plug and a rubber boot at each end.

How many ohms should a spark plug read?

When spark plugs are new, the resistance value is between 500 and 3000 ohms. As the plug ages, values below 5000 ohms are acceptable. But once the plug’s resistance value exceeds 5000 ohms, the plug should be replaced.

### How do you check spark plug wires?

Attach the test light to a good engine ground. With the engine running, move the test light along the length of each spark plug wire. If a spark jumps from a plug wire to the test light at any point, this is an indication that the insulation has broken down, and the spark plug wire should be replaced.

What is a reasonable voltage at the tip of a spark plug?

If the spark plug is properly connected, usually the voltage for it must be 12,000 to 25,000, or 5,000 to 9,000 volts if it goes higher. This means they discharge more current and produce sparks that are longer lasting and hotter.

## How much resistance should a spark plug wire have?

Question: How many Ohms of plug wire should be used? Answer: Usually between 10,000 and 12,000 ohms of resistance per foot of wire.

What spark plug resistance is normal?

between 500 and 3000 ohms
When spark plugs are new, the resistance value is between 500 and 3000 ohms. As the plug ages, values below 5000 ohms are acceptable. But once the plug’s resistance value exceeds 5000 ohms, the plug should be replaced.

### What happens if spark plug wire resistance is too low?

Lower resistance means more of the ignition coils energy is going towards bridging the gap or the spark plug. That hotter spark can create a more even burn of the fuel/air mixture in the cylinder, and thus, more power output from the engine.

How can you tell if a spark plug wire is bad?

Common signs of failing spark plug wires include a decrease in power, acceleration, and fuel efficiency. In addition, the engine light coming on or visible damange to the cables can be signs of a failing wire.