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Does Ignition Coil Have to Be Grounded

Does A Motorcycle Coil Have To Be Grounded

To power the cylinders of your vehicle, an ignition coil is used as a part that will produce high voltage. The ignition coil inside your vehicle doesn’t need any electrical ground.

Does Ignition Coil Have To Be Grounded

But it surely needs thermal ground because of heat dispassion. Here, the ground can be painted but still, it will serve as a thermal dispassion point for your vehicle.

The coil must discuss the heat otherwise it may get burned and lead to further damages to your engine.

How to Ground Ignition Coil

How To Ground Ignition Coil

The ignition coil is grounded in two ways. Either through the points or the electronic system and also the block. You should not ground the coil to anything else.

You will find two electrical sides to the coil. The first one is the primary side which is not grounded as both the positive and negative sides are connected to the other parts of the ignition system.

And the other one will be the secondary side which is grounded but to the oil housing. So to ground your coil, you need to ground it to the oil housing. For this, you can use chrome if you want to avoid pain. 

Bad Coil Ground Symptoms

Here are 15 common signs:

  1. Poor Acceleration: If your car is having trouble accelerating, it could be due to a bad ground connection in the ignition coil.
  2. Reduced Fuel Efficiency: A bad coil ground can cause your vehicle not to get the same fuel efficiency level you expect.
  3. Uneven Exhaust Smoke: If you notice that your exhaust has smoke coming out of it in an asymmetrical shape, this is another lousy coil ground symptom.
  4. Engine Misfiring: Misfiring is when your engine runs but not smoothly or efficiently. This can be due to the weak ground.
  5. Poor Handling: If your car doesn’t handle well, it could be due to an issue with the coil ground.
  6. Rough Idling: If your engine has difficulty running when idle, this is another symptom of bad ground.
  7. Loss of Power: If your car feels weaker than it should be, it could be a sign that the coil ground is terrible.
  8. Check Engine Light: This is one of the first signs of a problem you should note. This is your car’s way of telling you that there is a problem that needs to be looked at immediately.
  9. Weak Start: If it takes longer than usual to get your car started, there could be bad ground causing the issue.
  10. Sputtering: If your car sounds like it is struggling to stay running, it could be a sign of weak ground in the ignition coil.
  11. Random Stalling: If your car randomly stalls or shuts off while driving, it could be due to the coil ground not getting enough power.
  12. Engine Vibrations: If your engine is vibrating more than usual, this could be a sign that the coil ground is faulty.
  13. Poor Spark Plug Performance: If your spark plugs are not performing as well as they should, it could be due to a bad ground connection.
  14. Low Compression: Low engine compression can indicate bad coil ground.
  15. Bad Engine Mounts: If your engine mounts are wearing out quickly, it can also be due to a weak ground connection.

What Sends Signal To Ignition Coil 

The signal from the computer starts from the ignition switch and is sent through a couple of relays and switches, eventually leading to the primary circuit that connects the coil.

Ignition Coil Good But No Spark What To Do

You must start by testing the ignition coil to diagnose and troubleshoot this issue. The easiest way to test an ignition coil is to use a voltmeter to measure its voltage. If the voltage is low or non-existent, your ignition coil is likely bad and must be replaced.

What Happens If You Ground A Coil?

When you ground a coil, the electricity generated by the coil is diverted to the ground instead of its intended recipient. This bypasses any other elements involved in the circuit and acts as a safety measure. Any accidental discharge from the coil is redirected to the ground, allowing it to discharge without any potential danger.

Where Do The Ignition Coils Get Their Ground?

Most vehicles have the ignition coil grounded directly to the vehicle’s body, usually in the engine compartment. 

Does A 12v Ignition Coil Need To Be Grounded?

Yes. If a 12v ignition coil is not grounded correctly, it can lead to electrical malfunctions in the vehicle. 

How Do You Test An Ignition Coil Electrically?

Here’s what you need to know about testing an ignition coil electrically:

1. Remove the electrical connection from the coil

First and foremost, you’ll need to remove the connection between the coil and the vehicle’s electrical system. 

2. Install an ohmmeter or multimeter

To test the ignition coil, you’ll need an ohmmeter or multimeter to measure the coil’s resistance. 

3. Look up the appropriate resistance range

Make sure your coil is within this given resistance range – if it falls outside of the range, then you’ve probably found your problem.

4. Test the primary and secondary winding resistance

Once the multimeter is connected, test the primary and secondary winding resistance. If the resistance reading is far from the recommended 1:1 range, the ignition coil is likely faulty.

How Do I Know If My Ignition Coil Has Power?

The first test is to attach a spark tester to the ignition coil and crank the engine. If you see a bright blue spark, you know your ignition coil has power and is in good condition.

Can You Test A Coil With A Multimeter?

Yes, you can! A multimeter is an essential electrical testing tool for measuring various electrical circuits, systems, and components.

What Is The Life Of Ignition Coil?

The life of an ignition coil can vary greatly depending on whether it is a direct OEM replacement or an aftermarket part. On average, ignition coils last anywhere from 30,000 – 100,000 miles.

How Many Ohms Should A Ignition Coil Have?

The coil’s primary should be anywhere from 0.2 to 3.0 ohms, while the second should measure 5 to 20 kiloohms.

Can the Ignition Coil Be Repaired?

Yes. It is possible to repair the ignition coil if the damage is not too severe. That said, the repair job must be done correctly. One wrong move and the engine won’t start at all.

How Do You Test An Ignition Coil With A Screwdriver?

The first step in testing an ignition coil is disconnecting the ignition coil wire from the spark plug. Then, use the screwdriver to bridge the voltage across the two terminals.

When you do this, you’ll create a spark showing the resistance level in the ignition coil. If the resistance is within the tolerance range, the ignition coil works properly. 

The voltage should be consistent each time, indicating that the ignition coil is in working order.

And that’s it. You have successfully tested an ignition coil with a screwdriver. The entire process should only take a few minutes.

Does a Motorcycle Coil Have to Be Grounded

Does A Motorcycle Coil Have To Be Grounded

Again, a motorcycle coil doesn’t need to be electrically grounded. It doesn’t need to be grounded to the frame or somewhere else.

Only incidentally the high-tension wires are grounded that too by the virtue of the fact that, to get the current from plug to plug, the high-tension circuit uses the head.

A motorcycle coil will need a thermal ground for heat dispassion. It is better to use chrome as a heat dispassion point, paint can also be used as it will still serve as a heat dispassion point. But it will be better if you avoid corks.

If No Ground to the Ignition Coil what will happen

High-voltage sparks fire the engine and the ignition coil produces high-voltage sparks. The coil needs to be thermally grounded.

It is important for your engine as it will let your engine displays the heat. If there is no ground, it can cause spark issues, and eventually, your engine will face many difficulties. A lack of ground will also cause a weak spark.

You will always need proper voltage to the coil and also good ground inside your dist. Otherwise, you will have spark issues. 

What does Grounding Coil mean

As we know now, usually the coils are grounded through the wire harness. The mounting boss, which is on the coils, is not in contact with coil ground.

In case you want to run a new ground for your coils, you’ll have to either modify the wiring harness or you can create an adapter.

If one does this, one can combine the ground wires into a ring terminal and then mount it to the unused threaded hole that is located above the spark plugs of the front housing.

Does an MSD Coil Need to Be Grounded 

Yes, but the only MSD coil that requires grounding is the one that is used with the Pro-Mag setup. It has terminals to conduct this. All the MSD coils do not require any kind of external grounding. The primary and secondary sides will always be connected to the coil.

The black wire is connected to the CD box that is connected to the large black power wire connected to the battery.

With MSD 6 or 7 wiring diagram the ground path for the secondary high-voltage is back through the box to the battery. And it goes to the engine from there. By grounding the coil directly to the heads the spark energy is confirmed to the engine.

How to Test Ignition Coil

How To Test Ignition Coil

You should test your ignition coil from time to time. To test your ignition coil, first, connect the multimeter to the positive side or terminal of the coil and also to the high output side or terminal that directly goes to the spark plug.

Now check if the coil is performing okay by measuring resistance.

The secondary resistance for most ignition coils is between 6000-10000 ohms. You can also refer to the manufacturer for ensuring the correct range.

Do LS Coils Need to Be Grounded 

No, any external grounding is not needed. The valve covers on the LS engines are insulated from the head by the rubber gaskets. It has to be grounded to the cylinder head as the coils are discharging to that. You shouldn’t ground it to the frame.

The harness grounds to the head and you just have to extend the harness for connecting the coils.

Ignition Coil Wiring Diagram 

12 Volt Ignition Coil Wiring Diagram

Negative Side of Ignition Coil

The side terminals of the ignition coil are marked. The positive side is marked as (+) and the negative side is marked as (-). These are there so that you can measure the resistance. You have to set the multimeter to the 200-ohm setting.

Then attach the leads to the terminal markings, here red is positive, and black is negative. If you hold the coil making the plug wires go left, the negative side is on top and the positive on the bottom.

The power from the ignition switch goes to the plus side and the negative side goes to the distributor. 

Ignition Coil Wiring Diagram 

Frequently Asked Questions

How is an Ignition coil earthed?

The ignition coil is earthed through laminated windings. These windings hold the whole thing. The HT side picks up earth always through the spark plug. You can see it when you hold the pluck against the engine block.

Does the Ignition module need to be grounded?

It wouldn’t unless it is illuminated. In the case of boiler ignition, grounding is a must. Otherwise, everything that is mounted to the engine will be grounded through the engine. The voltage regulator also might need grounding. If it gets a power wire it should also have a ground wire. 

Can bad ground cause no spark?

Yes, the bad ground can cause weak or no spark at all. As we know, high-voltage sparks fire the engine and the ignition coil produces high-voltage sparks.

The coil needs to be thermally grounded otherwise it won’t be able to pass heat. You are always going to need proper voltage to the coil and also good ground inside your dist. Otherwise, you will have spark issues

Does the negative side of the coil go to the ground?

Yes, one end of the secondary winding, which is the negative side, goes to the ground. The coil produces high voltage after that the output goes to the positive terminal, from where it jumps the spark gap to return to the ground and thus completes the circuit.

What is the negative side of an Ignition coil?

The negative side of an ignition coil is marked as (-) or painted black. The sides are there so that you can measure the resistance. The negative side usually goes to the ground. The power from the ignition switch goes to the plus side and the negative side goes to the distributor

Does a 12V coil need to be grounded? 

No, it doesn’t need to be grounded. The coil is grounded in two ways. Either through the points or the electronic system and also the block. You should not ground the coil to anything else.


Now we know that To power the cylinders of your vehicle, an ignition coil is used as a part that will produce high voltage. To produce the high voltage, certain requirements must be met so that it can fire the engine.

Facing problems can be as simple as a weak battery or a corroded wire. The basic conditions are a good function of the ignition system. If things get complicated, it may contribute to sparking loss and further damage.

Knowing what to look for and where to look in case of troubleshooting is the key to saving the engine. You should check your ignition coil from time to time to ensure its efficiency.  

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