A bad distributor is not a headache for a driver who owns a vehicle built after the 2000s. However, if you are among the proud owners of older high-mileage cars, you shouldn’t be surprised if it is acting up.
Rough idling, surprise stalls, or taking forever to start are a few of the many symptoms you can face with a distributor gone bad. A bad distributor disrupts the smooth operation of your engine, making your every drive a struggle.
But the good thing is you can tackle the problem before it gets worse. In this blog, we will explore the 10 most common symptoms of a failing distributor and how you can fix them.
There is no technical overload. Just straight talk for drivers who want to stay ahead of costly repairs.
What Is a Distributor?
A distributor is an integral component in older ignition systems (mainly pre-2000s vehicles). It helps in the smooth startup of your vehicle by directing high-voltage electricity from the ignition coil to the right spark plug, and that too at the right time.
How It Works
While the complexity of the engine and its components is not for everyone, it is still wise to learn what each part does. The spark plug is known to provide the basic ignition, but that power reaches it through a series of steps:
- Ignition coil generates high voltage.
- Rotor inside the distributor turns with the engine.
- Rotor passes each terminal in the cap, sending a spark to that cylinder.
- Spark plug ignites the air/fuel mixture in the combustion chamber.
10 Top Symptoms Indicating Your Distributor Has Gone Bad
You will not end up with a degraded distributor abruptly. There are several signs along the way telling you to handle the problem. Whether you didn’t catch up on the signs or chose to ignore them, you will have a busted engine part that will not only cause you trouble on the road but also require you to empty your pockets to get it fixed.
So, if you do not wish to be slapped with unwanted expenses, you need to learn the different symptoms of a bad distributor.
1. Random Engine Misfires
Think back to the time when you were driving with ease, and suddenly your engine stuttered. That jolt you felt is likely a misfire, and your distributor could be the culprit.
A healthy distributor times each spark plug to ignite precisely. However, when it starts to fail, the spark timing gets inconsistent, resulting in an unpleasant jerking sensation while idling or accelerating. If you ignore it, the damage can seep into the catalytic converter, an expensive engine part to fix.
2. Hard or No Starting
If your beloved engine cranks but does not start or takes significantly longer than usual to roar, there are chances it might not be getting any spark. Worn internal contacts, cracked rotor, or moisture inside the distributor can all prevent the spark from reaching the plugs.
It will only get worse during damp weather and chilly mornings. Instead of guessing the hit or miss with your engine, pop up the hood and inspect that distributor immediately.
3. Engine Stalls While Driving
As a driver, there is nothing more frustrating than your engine suddenly dying on you in the middle of the drive. It gets even more dangerous if you are in bustling traffic or the middle of nowhere.
Unexpected engine stalls are another classic sign of a distributor wanting attention. You will find your engine randomly stalling and then restarting a few minutes later as if nothing happened. If this unpredictable and unnerving thing occurs without warning, this part is one of your prime suspects.
4. Rough Idling
If you feel your car vibrating more than usual at stoplights or in traffic, it is not to be taken lightly. That shaky or uneven idle is generally due to the distributor being unable to divide the spark evenly to all cylinders.
Spark skipping or hitting the wrong plug at the wrong time is highly likely to happen if the distributor is worn out or dirty. This creates an imbalance in the combustion, causing you to experience a jittery engine even when you are not pressing down on the gas.
5. Loss of Power
If your car hesitates to start or feels sluggish or underpowered after you start it, it is something to look into. A bad distributor is unable to keep up with your engine speed, making your car struggle with performance. This is even more obvious when you are either accelerating or climbing uphill. Loss of power is a clear indicator that the spark is not reaching all the cylinders when it should.
6. Popping or Sputtering Noises
If you are frequently hearing odd popping sounds from the exhaust pipe of your vehicle, this is often a sign that your car is backfiring. It happens when the distributor’s timing is way off compared to the engine.
In such scenarios, it can send the spark when the exhaust valve is open, igniting the fuel outside the combustion chamber. This is not only dangerous but also hints at bigger problems with your ignition control.
7. Visible Moisture or Corrosion
The presence of moisture or corrosion is another reason why your distributor is unable to perform well. To know for sure, pop the distributor cap off and take a good peek inside.
If there is moisture buildup, rust, or greenish corrosion, you need to act fast. Even a fine white powder inside the cap can disrupt the spark flow.
This particular symptom is highly common in older vehicles that are either driven in humid climates or sit in for long periods. If not handled in time, it can lead to other signs on this list.
8. Burn Marks or Carbon Tracks
If, during your inspection of the distributor, you find dark, thin lines carved into the plastic of the cap, it is carbon tracking. It means that the electric current in the engine is flowing to the wrong terminal.
All the burn marks you see usually form from repeated occurrences. Their appearance is an indication that you need to replace the cap and rotor as soon as possible.
9. Inconsistent Timing
If your car runs okay but you notice slower acceleration, low throttle response, and increased fuel and engine oil consumption, a worn distributor with a worn shaft or broken advance mechanism is involved. You can perform a timing test to confirm it. But if you are experiencing other subtle symptoms associated with this engine part, the timing may already be off.
10. Check Engine Light
Many older cars do not come with sensors like modern ones. However, some of them still have an ECU that displays a code if something is seriously wrong with the car.
If you find your check engine light illuminated and notice any of the above-mentioned symptoms, there is a good chance your distributor is the troublemaker.
What Causes a Distributor to Go Bad?
As a car owner, you need to understand the fact that even with good maintenance, a distributor will eventually wear out. The older the car, the more likely the chances of occurrence. Time, heat, and driving environment all take their toll on your car.
Lesley, who is quite familiar with the automotive mechanism, missed out on this one part, causing her beloved five-seater SUV to break down and her ending up paying hundreds of dollars to get it fixed.
If you do not want to be out of money, always look out for these most common causes:
Moisture in the Cap
The distributor caps will crack or lose their seal over time, making the part prone to moisture. This dampness then consistently interferes with spark delivery, often causing misfires or rough starts.
Worn Cap and Rotor
With its every spin, the rotor creates tiny wear marks inside the cap. And with thousands of miles on your car, those marks burn or corrode, leading to weak or inconsistent spark. If your distributor’s original and your car’s past 100,000 miles, it is worth examining.
Carbon Tracking and Arcing
Every time the spark jumps to the wrong contact point, it leaves behind thin, black lines that act like shortcuts for electricity. These carbon tracks are usually caused by moisture, dirty caps, or old plug wires and will keep on causing misfires until you replace them.
Broken Advance Mechanisms
Older distributors rely on vacuum or mechanical advances to adjust timing. And if those systems break, your engine may hesitate, feel sluggish, or run poorly under load.
Heat and Vibration
Your distributor is present on top of your engine and exposed to severe heat and vibration. After years, this exposure can lead to internal parts cracking, warping, or failure. Thus, every time you are working on your engine, it is wise to inspect the distributor as well.
What Should You Do If You Suspect a Bad Distributor?
If your beloved automobile is showing multiple symptoms of a worn-out distributor, the first thing you need to do is inspect it for cracks, burn marks, corrosion, or moisture.
If you do not find any such extensive signs but still have doubts, look out for the patterns of issues like hard starts on rainy days or engine stalls after warming up. Finding patterns can help you pinpoint the issue faster.
Inspecting the part can also help you confirm whether the problems you are facing are linked to the distributor or something else in the ignition system. If you are familiar with the technical composition of your engine and have the right tools, you can do it yourself. If not, take your ride to a trusted mechanic.
If your distributor is not the main culprit but is worn or starting to degrade, do not patch it. Instead, replace it with a compatible one. It can easily cost you between $100 and $400, plus the labor. While this fix may seem pricey to many, it can completely restore the performance of your engine.
How to Fix a Bad Distributor
If you are 100% sure that you have recognized some of the symptoms associated with degraded distributors, you need to take the right action. If the damage is not severe, you may move ahead with repair. And if the depletion is too much, you will need a brand-new one. Here is a step-by-step guide to help you get started.
1. Pop Up The Hood
Start by opening the hood of your car and securing it well to ensure it does not close midway through your work.
2. Locate The Distributor
Once the hood is properly secured, the next step is to locate the distributor within your engine.
3. Inspect The Cap and Rotor
Start by inspecting the cap and rotor, as they are the most common points for failure. If you find any wear or buildup, replace them right away.
4. Inspect On The Inside
If everything on the outside looks fine, take off the cap and look for cracks, rust, white lines, or carbon buildup on the interior surface of the distributor. If the damage is too much to ignore, you need to install a new distributor right away.
5. Test The Functionality
If everything is fine on the inside, do not get hasty with giving yourself a pat on the back for a job well done. Sometimes, the problems are just building up, and we can miss them in visual inspection. So, test the distributor for its functionality.
Use a voltmeter to check the electrical connections of the part. Do not forget the spark plug wires. I would also recommend checking the timing of spark plugs. It is necessary because if you are unable to pinpoint any visible issue and the distributor still keeps acting out, bad timing might be the culprit.
If this entire process seems too much, please take your ride to a professional mechanic instead of going all DIY on it and making an even bigger mess.
6. Clean The Distributor
Once you are done with all the inspection of parts and wiring, it is time to clean the entire area. Ensure every part, from the cap and rotor to the distributor’s contacts and connections, is dirt, dust, and corrosion-free.
7. Replace The Cap and Rotor
After cleaning, it is time to replace the cap and rotor of the distributor. Replacing the cap and rotor is an easy task if you have the necessary skills. All you need is basic tools and follow the repair manual. However, if you find no change even after this replacement, your ride may require replacing the entire distributor.
Frequently Asked Questions
How much does it cost to fix a distributor?
On average, it will cost you around $40 to $100 for a cap and rotor and $100 to $400 for an entire distributor replacement at home. In a professional setting, you will end up paying $75 to $150 more in labor charges.
Can a bad distributor cause a loss of power?
Yes. By disrupting the spark timing it leads to misfires, poor combustion, and reduced engine efficiency.
What does a bad distributor sound like?
It generally causes the engine to sound rough or uneven. You can hear popping or backfiring through exhaust or intake, skipping sound under load, and occasional sputtering or hesitation during acceleration.
How to tell if the installation has gone wrong?
If, after installing the new distributor, the symptoms related to the bad ones keep showing up, your installation has gone wrong.
Conclusion
A distributor will degrade with time. However, it requires your immediate attention if your car keeps on stalling while on the road or won’t start at all. By keeping an eye out for signs of a failing distributor, you can fix the issue before it turns into bigger engine trouble, costing you more money or even your engine.
