How to Fix a Car That Won’t Start Intermittently: A Step-by-Step Guide
There are few things more frustrating than getting into your car, turning the key, and hearing nothing. And when that problem happens intermittently, it can be even worse—because you never know when it’s going to leave you stranded. If you're like me, you’ve probably faced this issue at some point. Maybe it’s a cold morning, and you’re in a rush, but your car refuses to start for no apparent reason. Or perhaps it starts fine one day, but the next day, it’s a completely different story. This kind of intermittent starting problem can be tricky to diagnose and fix. However, over the years, I’ve learned a few ways to tackle this issue—and in this guide, I’ll share what I've learned.
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1. Check the Battery
The first thing I always check when my car has intermittent starting problems is the battery. A battery can still show signs of life and seem to work fine, but it could be weak enough to cause issues. It’s a common cause of intermittent starting problems, especially when the battery is beginning to fail. If the battery is old (over 3-5 years) or has been subject to extreme temperatures, it’s likely the culprit.
I remember the time my car wouldn’t start properly for a few days, but it would start on the third or fourth try. After some troubleshooting, I realized the battery was only weak enough to turn over the engine sometimes. I had it tested, and sure enough, it was on the verge of dying. Replacing the battery resolved the issue instantly.
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1.1 How to Check the Battery
To check your battery, you can use a multimeter to measure its voltage. If the reading is below 12.6 volts when the engine is off, the battery is likely not charging properly. A fully charged battery should read around 12.6 to 12.8 volts. Additionally, if the car cranks slowly or makes a clicking noise, the battery could be the problem. If you're unsure, most auto parts stores will test your battery for free.
2. Investigating the Starter Motor
If your battery is in good condition, the next part I always check is the starter motor. The starter motor is responsible for turning the engine over when you start your car. If it’s malfunctioning, it may only work intermittently, causing that frustrating “sometimes it works, sometimes it doesn’t” issue.
I had a situation where my car wouldn’t start consistently, and after checking the battery, I moved on to the starter motor. It turns out that the starter motor was faulty and needed to be replaced. The car would sometimes start, and other times, the engine would make a grinding noise and not start at all. Replacing the starter motor fixed the problem and solved the issue once and for all.
2.1 How to Check the Starter Motor
Check for signs like a clicking sound when you turn the key, or no sound at all. You can tap the starter gently with a hammer or a tool (be careful!) while someone else turns the ignition. If the car starts right after tapping, it could be a sign that the starter is sticking and needs replacement.
3. Inspect the Fuel System
Fuel delivery issues can also cause intermittent starting problems. When the car starts sometimes and not others, it could be due to a clogged fuel filter or a failing fuel pump. I encountered this issue once, where my car would crank but not start, and after a few tries, it would start up. After some investigation, I realized that the fuel pump was intermittently failing, not providing the necessary fuel pressure to the engine.
3.1 How to Check the Fuel System
If you suspect a fuel issue, listen for a humming sound from the fuel pump when you turn the key to the “on” position. If you don't hear it, the fuel pump may be faulty. Another test is to check the fuel filter—if it's clogged, it can restrict fuel flow to the engine, causing intermittent starting problems. Replacing the fuel filter is an easy and inexpensive fix that can save you a lot of headaches.
4. Examine the Alternator
The alternator is another key component in your car’s starting system. While the alternator doesn’t directly cause the engine to turn over, it does provide power to recharge the battery. If the alternator is failing, it could lead to a battery that isn't charging properly, causing intermittent starting problems. I’ve personally experienced this with my old car, where the alternator would intermittently fail, resulting in starting issues that only got worse over time.
4.1 How to Check the Alternator
To test the alternator, you can use a multimeter to measure the voltage while the engine is running. It should read between 13.7 to 14.7 volts. If it’s lower than that, it could indicate that your alternator isn’t charging the battery properly. Another sign of a bad alternator is dimming headlights or electrical issues while driving.
5. Inspect the Ignition Switch
Another potential cause for intermittent starting problems could be a faulty ignition switch. If your ignition switch is worn out or faulty, it may not send the proper signals to the car’s electrical system, which can prevent the car from starting. This was the issue I faced with my old sedan, where it would fail to start unless I wiggled the key a certain way in the ignition. Once the switch was replaced, the problem was solved.
5.1 How to Check the Ignition Switch
To diagnose an ignition switch issue, try jiggling the key in the ignition while trying to start the car. If this makes the car start, then the ignition switch is likely the problem. Additionally, the issue may present itself as flickering dashboard lights or problems with the starter motor engaging.
6. Check the Wiring and Connections
Finally, if none of the previous components are the issue, I’d recommend checking the wiring and electrical connections. Loose or corroded wires, especially those connected to the battery, starter motor, and ignition switch, can cause intermittent issues. This is especially true in older cars or vehicles exposed to extreme weather conditions.
6.1 How to Check the Wiring
Visually inspect the wiring around the battery, starter, and ignition switch for any loose, frayed, or corroded wires. If you find any, you may need to repair or replace them. Corrosion can build up on battery terminals and wires, preventing proper electrical flow and causing starting issues.
If you're not comfortable checking these components yourself, it's a good idea to seek professional help. A reliable towing or roadside assistance service can also help get you to a mechanic if you’re stuck on the road.
If you're in need of roadside assistance, I highly recommend checking out Rescue & Towing. They offer expert help for all kinds of car troubles, including intermittent starting issues.
