21 Aug Vehicle Ignition System: What Are The Common Issues?
Back when I was a young adult, my best friend’s ride was the only one big enough for all six of us to drive around town together. The problem was that it never wanted to start. I have tons of memories of jumping out of the thing to give it a good push so he could pop the clutch to get it started. These days, most modern cars don’t work that way anymore. Not to mention, I’m far past wanting to push a car for any reason. When experiencing car stalling or misfires, there’s a good chance the spark plugs or another part in your ignition system is failing. Since your vehicle’s ignition system is pretty complex, let’s review how it works.
How Does The Ignition System Work?
Starting a motor vehicle involves much more than just turning the key or pushing a button. All the ignition system components must work in unison to start a combustion engine. The first step is turning the key (or pressing the Start button). After that, the combustion process follows many paths to ignite the fuel and create enough energy to power the engine. If an issue happens anywhere in the ignition system, the engine won’t start. Let’s read about the components to learn what they do.
Ignition System Components
Not every vehicle on the road today contains the same exact ignition system components. They have evolved over the years, and of course, auto manufacturers use different variations of the components on their specific models. So, in a basic sense, here they are:
Ignition Switch
The ignition switch controls the electrical current between the car battery and the ignition system. It activates with a key or a push button found on the steering column or dashboard.
Ignition Coil
The ignition coil is a high-voltage electromagnetic part that converts low-tension (LT) current from the car battery into high-tension (HT) current. It creates the powerful spark necessary to ignite the fuel vapor.
Distributor, Distributor Cap, Rotor
The distributor directs the current from the ignition coil through the distributor cap to the spinning rotor, which sends the spark to each spark plug in order.
Distributor Pick-Up Coils (Hall Effect Sensor)
In distributor-style ignition systems that do not use breaker points, each distributor has a pick-up coil (also called a hall effect sensor) that reads a cog wheel inside the distributor to accurately tell the precise moment when to send a signal to the coil to fire. They perform the same function as a crank position sensor.
Crank & Cam Position Sensors
- Modern ignition systems that don’t use a distributor use a crank position sensor to determine the precise moment to fire the ignition coils. It is essentially a magnetic trigger that sends a signal at the exact correct moment in the rotating crank.
- A cam position sensor reads the position of the engine’s camshafts (or multiple camshafts) to gauge the correct ignition timing. It will either advance (speed up) or retard (slow down) the stroke.
Ignition Module/Ignition Control Unit
Ignition modules were standard in many electronic ignition systems from the late 1970s through the early 2000s. Foreign vehicles may refer to the ignition module as a ‘power output stage control’ or ‘ignition control unit’. The ignition module processes the signals from either the crank position sensor or the pick-up coil (in a distributor ignition system). It sends the signal when to fire the coil. Vehicles made over the last decade or so no longer use an ignition module since its’ function is now performed in each individual coil or by the onboard computer.
Spark Plugs & Spark Plug Wires
- On older vehicles, each contact point on the distributor cap connects to a spark plug wire that directs the spark to the spark plug. The spark plugs screw into the combustion chambers of the cylinder head, where the hot spark ignites the air/fuel mixture thousands of times per minute.
- Newer vehicles eliminate the central distributor and instead utilize a coil on each spark plug. The coils connect directly to the engine’s onboard computer or the Engine Control Unit (ECU). This method gives the ignition system more precise control over the timing of the spark plug. It also removes the need for a distributor and the spark plug wires since the ignition system applies the charge to the plug.
Common Ignition System Issues
It’s important to remember that auto manufacturers design vehicles differently from each other and differently across their available models. Therefore, ignition systems also differ from car to car and from year to year. Regardless of which specific ignition system your vehicle has, chances are one or more of these components may cause trouble when you have an issue.
Vehicle Won’t Start
Nothing is more frustrating than needing to go somewhere, and your vehicle won’t start. While several things may be causing this issue, we are focusing on just the ignition system here. You can pull out your owner’s manual to troubleshoot your vehicle-specific components or have your local auto service center help you. The more information you can provide, the faster you can resolve the issue. Things to inspect:
- Sensors and Modules
- Ignition Switch
- Spark Plugs
- Wiring or Blown Fuses
- Key Fob Batteries
Car Stalling
In a perfect world, your car should never stall while driving or idling. If you notice a rough idle, coughing engine, or performance issues, please schedule a diagnostic service appointment. Possible problems causing car stalling can be:
- Faulty Sensors
- Failing Ignition Switch
- Old or Worn Spark Plugs
- Bad Ignition Module
Engine Misfires
That super loud BANG that scares your whole neighborhood and makes your heart race is an engine misfire, and they can really damage your engine if not addressed. Ignition system issues are not the only things that cause engine misfires. (You can read about your vehicle’s fuel system here.) Ignition system components to look at if your car misfires:
- Bad Ignition Coils
- Distributor producing a weak spark
- Failed Spark Plugs
- Faulty Sensors
Dashboard Warning Light
I always get nervous whenever my dashboard lights up with one (or more) of those warning lights. Ignition system issues often trigger the Check Engine or the Key light. An OBD-II scanner can pinpoint which code caused the light to turn on. This information is really helpful to your service technician, as it narrows down the possible culprits. While ignition system components are not the only ones that trigger the Check Engine light, here are the top contenders:
- Ignition Coil
- Sensors and Modules
- Spark Plugs
- Ignition Switch
- Key Fob
Ignition System Service in Jacksonville, FL
At JJ’s Auto Care, our ASE-certified mechanics use state-of-the-art diagnostic equipment to diagnose your vehicle’s ignition system issues. Let us inspect, repair, or replace faulty sensors or spark plugs to remedy your car stalling and misfires problems.
Schedule Ignition System Service
Call us at (904) 721-6646 or visit us online to schedule your ignition system service today!
JJ’s Auto Care in Jacksonville, Florida, Offers:
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- 12 month / 12,000 mile nationwide warranty
- Free roadside assistance with a nationwide warranty
- Shuttle service (within five miles)
- Free WiFi
- Comfortable waiting area with coffee bar