6 Ways To Start A Car With Bad Spark Plugs

6 Ways To Start A Car With Bad Spark Plugs

Does a bad spark plug cause you to experience a hard car start? While the vehicle sparking plug is an essential device in your car, there is a slim chance you will have it serviced in due time, eventually making it wear out.

For this reason, you might find yourself having a failed car start because of bad spark plugs. So, how can you ignite your engine with a faulty spark plug?

Starting a Car with Bad Spark Plugs

Luckily, there are ways you can get your car moving, even with bad spark plugs. Please look at our guide on starting a car with bad spark plugs.

How To Start A Car With Bad Spark Plugs

Despite struggling to get your engine running, a failing spark plug has several other inconveniences that may cause you to suffer: rise in fuel consumption, engine knocking, poor acceleration, and engine misfiring.

The big question is, how will you start your car with bad spark plugs? Here are all the answers that will aid overcome the problem.

1. Gap Your Spark Plugs

The gap is the space between the center and the ground electrode. Gapping the spark plug is necessary to transmit electrons from the combustion cylinder successfully.

Early warning signs of poorly gapped sparking plug include decreased acceleration power, rough idling, and engine hesitation.

When the gap is extremely small or wide, it may cause engine misfires, Making it hard for your car to start.

Therefore, reducing or widening the gap will play a significant role by facilitating a smooth electricity supply on the running engine.

To gap your spark plug, first, you need to check on the owner’s manual to find the recommended distance between the electrodes.

After knowing the required spark plug gap, use your feeler gauge to measure the current space. The gap gauge will quickly pass through a wide spark gap and won’t pass through a too-small opening.

After studying the gap, get your spark plug tool; gently bend the side electrode towards the inner side when the opening is wide and an outside-bend if it’s too narrow. Finally, install the spark plug and start your engine.

2. Clean The Oil And Carbon Build-Up

The sparking plug is responsible for converting the compressed fuel mixture into the needed power for starting your car’s engine. The combustions occur on the sparkplugs electrodes.

Over time, the oil and carbon residue mount on the sparking plug electrodes, causing your car not to start because of the uneven transmission of electrons.

Common causes of oil and carbon residue on your car are poor fuel filters and long idling hours. Additionally, black soot on your spark plug electrodes results from oil and carbon residue.

The soot reduces the efficiency of your car’s spark plugs because the electrical currents are not transmitted accordingly.

It would help clean the carbon remains by first scrubbing the covered area with a sandpaper or wire brush to avoid this problem.

Spray out the dirt produced after washing with a car cleaner and let the spark plug dry before fixing it back.

Another solution would be burning off the oil and carbon build-up using a butane torch or a Sandblast (a machine that produces air pressure) to force out the soot mounted on the spark plug.

These methods enable you to start your car with a bad spark plug.

3. Check The Spark Plug Wire End

Consider checking the spark plug wire end if your car doesn’t start. The sparking plug wire end is the point that connects the terminal to the vehicle ignition coil.

When the cable connection to the spark plug is weak, it affects the power supply required to start your car. So, you should ensure that the end wires are well fitted for the complete transmission of electrons.

Foremost, you have to separate the spark plug from the plug boot. Typically, the plug boot is firmly fixed to the spark plug; therefore, it might require lubrication to remove it quickly.

You must check for loose-fitting cable in the Snap Lock Plug Grip. If the thread is weak, you need to fix it tightly and install it back.

4. Seal The Cracked Cylinder Head

Sealing the cracked cylinder is another way to start your car with bad spark plugs.

The spark plug position is on the cylinder head, and the cylinder chamber is where the fuel mixture compression occurs to produce sparks that will pass through the plug electrodes.

Ways To Start a Car with Bad Spark Plugs

If the cylinder head is faulty, you will not achieve complete combustion, producing less ignition power. Early signs of a cracked cylinder head include engine overheating, dirt in the oil, and engine misfires.

To correct the faults caused by the cracked cylinder, you should get a sealant to protect the broken area.

The sealer will shut the pressure escape routes and enable a complete compression of fuel mixture to provide enough power to your engine.

5. Preheating The Spark Plug

The electrodes of a fouling spark plug are affected by cold temperatures, hindering enough energy production from sparking the engine.

You will have a problem starting your car because the electron’s currents are not supplied sufficiently.

Many car owners have confessed that preheating the spark plug to ignite the engine when experiencing a car failed start works.

Some preheat the spark plug by placing it in the oven for a few minutes, while others use a heating torch.

To get your engine easily cracking, you need to heat your spark plug to its recommended heat range.

Although there is no evidence showing that warming up your sparking plug will damage the car engine, some drivers discourage the practice as they fear it might bring more harm than good.

6. Replace The Spark Plugs

You may need to replace the bad spark plugs if you want your car’s engine to start. If you’re going to replace the spark plugs, you should know how to do it correctly.

First, disconnect the battery cables and open the hood of your car. Then, you can remove the old spark plugs, which may be difficult due to the tight-fitting.

Once done, you have to clean the spark plug holes and remove any debris stuck inside. Afterward, you have to fit new spark plugs.

When replacing the spark plugs, you also need to clean the spark plug wire. You have to remove the old wire before installing the new one.

To avoid damaging the wiring during the replacement process, you need to use an electrician’s tool called a wire stripper.

Once you clean the spark plug wires, you need to reinstall them. You can either tighten the wire or push it into place. However, it would be best to tighten the spark plugs after the engine has warmed up.


Sparking plugs takes a long period before there is a need to buy a new one. Therefore, you might not be keen on its current condition and have it repaired soon.

Because of delayed services, you may unpredictably undergo a failed car start because of a faulty spark plug.

So, whenever you have a bad spark plug, it’s good to have in mind all the working tricks that will make your engine rerun.

Furthermore, you will save time and the repairing cost. Finally, the guide above helps prevent future engine complications caused by a faulty spark plug.