[SOLVED] 5.7 Vortec No Spark From Coil

The coil is one of the most important parts of your vehicle. It provides the spark which causes your ignition to start. If your vehicle isn’t starting because there’s no spark from the coil, you might have a couple of issues like 5.7 Vortec no spark from coil. No matter what the reason is, it’s ideal that you start working on diagnosing and repairing the issue immediately. Not only is it very inefficient to have a malfunctioning coil, but it can also be dangerous. 

The 5.7 Vortec is a well-performing and reliable engine that is used in GMC and Chevy trucks. Arguably the best part about this engine is that any of the parts are very easily found and replaceable. In fact, you almost never have to call a mechanic and can fix a lot of the spare parts (such as coils) by yourself. 

Why is there no spark from my 5.7 Vortec Coil? 

Here are some of the causes for no spark from your 5.7 Vortec Coil: 

  • Faulty spark plug
  • Battery issues
  • Corroded wires
  • Distributor cap

However, if you’re facing the issue of your vehicle sputtering before it starts, this could be connected to the coils as well. We recommend you check out our article on this separate issue here.

Top 4 Reasons of 5.7 Vortec no spark from coil

5.7 Vortec No Spark From Coil

Here are some of the reasons why you’re facing the issue of your coil having no spark. While this is a generic problem, it can vary slightly from other engines. That’s why we’ve included troubleshooting information on how to diagnose and repair any issues that are absolutely specific to your vehicle running on a 5.7 Vortec, not any other engine!

We’ve also listed the reasons, causes, and solutions in the order of how you should approach it. A good rule of thumb to follow is to make sure you’ve attempted every kind of repair before you make the decision to replace any parts, big or small. That’s we’ve also included some kinds of reasons and causes that don’t require any expensive replacements, or calling a local mechanic since that can be expensive as well. 

Here are the top 4 reasons why your coil has no spark: 

Reason #1: Faulty Spark Plug

Faulty Spark Plug

Spark loss directly impacts the ignition. If your coil isn’t sparking, you’re likely having trouble starting your vehicle. You have to primarily understand that ignition coils are electric. If there is any issue with the voltage transmission, then the job will not be done. The spark plug has an electrode gap that is supposed to transmit voltage. If this doesn’t happen for any reason, then the ignition coils won’t receive the energy they are supposed to. 

It’s quite common that your ignition coils are absolutely fine, but the spark plug can be malfunctioning or worn out. 

Solution: You will have to take a closer look at the spark plugs. This is slightly trickier than simply lifting the hood and having a good look at a part. You will have to detach the spark plugs from the vehicle and inspect them outside. Whenever you’re dealing with electrical parts it’s a good idea to take safety precautions. 

You’ll need an analog or digital multimeter to read the voltage of your spark plugs. If there’s any discrepancy here, you’ll know that it’s the spark plugs to blame and not your ignition coils.

Replacing spark plugs is very easy and shouldn’t take too much time or effort, or money!

Reason #2: Battery Issues

If you’ve taken a good look at your spark plugs and they have the right voltage and seem to be functioning absolutely fine, then we might want to look at the electrical aspect. The battery is also a common culprit for not sending sufficient voltage and causing the ignition coils to lack a spark. Your vehicle’s battery might be worn out over long periods of usage or due to overload and could be sending a weak signal which is less power than your vehicle requires. 

Battery Connection

Even if you take necessary precautions like switching off your AC when starting the vehicle, batteries can wear out due to other reasons. Let’s find out how we can be sure these are indeed battery issues and what we can do about it. 

Solution: This is another situation where you pull out the digital multimeter. You’ll have to check the voltage of the battery after taking the necessary precautions. Don’t treat these like triple AAA batteries, a vehicle the size of your Chevy Silverado needs a powerful battery that can still be dangerous even when it’s weak. 

Here’s a great video on how to check for battery issues. 

If it comes to this, you might need to replace your battery. We know this is a dreaded last resort since a battery can be expensive — but with battery issues, no spark from a coil is one of the smaller problems on your hands! Lucky for you, we’ve compiled a list of the best batteries for your vehicle here. 

Reason #3:  Corroded Wires 

You’ll be surprised at how common this particular problem is. You just figure out that there’s no spark from your coil, and then you decide to take a look at the spark plug. Even after the spark plug seems to be fine, you take a closer look at the battery: which thankfully is not emitting a weak voltage and seems to be absolutely fine. 

Corroded Engine Wires

The culprit might be the wires, which tend to get corroded and rusted after long periods. Even if they haven’t gotten corroded and are intact, they might be loose or damaged in some other way. Any kind of damage or corrosion to the wires gets in the way of the transmission of voltage, making the ignition coil completely spark-less. 

Solution: It’s very simple to understand this particular issue. Having a break in the circuit causes the issue of no spark being emitted from the coil. All you have to do is source replacement wires and your vehicle should be up and running. But while this will definitely solve the problem, you should also put some precautions in place that ensure you won’t have to do this again. 

If the wires were corroded, opt for replacement wires with a chromium finish. If you had the problem of damage or cut wires, you will need to inspect the insides of your car. You will most probably find that there are some sharp edges in the car itself that are getting in the way of your wire and are cutting into its protective sheath over time. You can cushion this sharp edge from the wire itself. 

Reason #4: Distributor Cap

Finally, if all else has failed, it’s worth taking a look at your distributor cap. A cracked or damaged distributor cap will prevent the smooth flow of electricity and then cause the voltage flow to be interrupted. 

Solution: Luckily for you, replacing a distributor cap is easy and inexpensive. You can also swap the old one for the new one on your own without having to call for extra help. However, we still recommend that you take the necessary precautions when working on the electrical components of your vehicle. 


We hope that you were able to solve the problem of no spark coming from your 5.7 vortec coil. We’ve listed the most common and prevalent problems, and we’re confident that you’ll be able to solve it on your own: whether it’s a faulty spark plug, issues with your battery, corroded wires, or your seemingly innocent distributor cap.

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