Your vehicle dying or stalling while driving is a frequent car trouble. The causes for this problem are many, ranging from a dead alternator to a faulty battery and a bad ignition switch.
But what about when a car dies while driving but restarts? Although not typical, a car can shut off while driving and then restart due to issues with fuel delivery. Sometimes, the problem could occur due to defective sensors, a vacuum leak, overheating issues, and ignition system problems.
Want to know in detail about diagnosing and fixing the cause of the problem? In this guide, we will delve into that.
Car Dies While Driving But Restarts: Causes and Fixes
When a car shuts off while driving but then restarts, it can occur for various reasons. Read on to find out what they are.
1. Fuel Delivery Problems
When your car’s fuel supply to the engine is disrupted, it could die while driving but restart. Generally, fuel delivery problems are caused by a faulty fuel pump, dirty fuel filter, and failing fuel injection systems.
If any of these components have issues, they can cause low fuel pressure, leading to the engine dying. This will mostly happen when your vehicle is under heavy load or accelerating.
After some time, your car can restart and run temporarily at lower speeds or loads. The reason is that the fuel demands on the pump and injectors will be minimal. Similarly, dirt in the filter may settle when the car shuts off, allowing for a brief restart.
Diagnosing and Fixing the Problem
- The best way to diagnose a faulty pump is to perform a fuel pressure test using a fuel pressure gauge.
- If the reading is zero, the pump is dead. For the filter, you can remove it and visually inspect it for debris and clogs.
- To diagnose failing injectors, place a long metal screwdriver against one of them. Then, listen for a clicking sound on the screwdriver’s handle. If there is no sound, the injector is bad.
The best solution for failing fuel pumps or injectors is to install new ones. But due to the job’s complexity, you should let professional mechanics handle it.
As for the dirty fuel filter, you can replace it yourself through the following steps:
- Step 1: Depressurize your vehicle’s fuel system by unplugging the fuel pump’s relay or fuse.
- Step 2: Detach the fuel lines from the filter.
- Step 3: Remove the old filter from its assembly.
- Step 4: Install the new filter in reverse sequence.
2. Defective Sensors
Some other common culprits of a car dying while driving and restarting are a failing MAF, camshaft, and crankshaft position sensors.
Typically, the MAF or Mass Air Flow sensor measures the precise amount of air that enters the engine. This helps ensure an ideal air and fuel mixture. Conversely, the camshaft sensor allows the engine to establish the crankshaft drive’s exact position.
As for the crankshaft sensor, it determines the crank’s position or rotational speed. This is essential for the engine’s timing and fuel injection.
If one of these sensors becomes faulty, they usually provide inaccurate or erratic data to the engine control module (ECM). This can cause your car to stall while driving due to the ECM making incorrect adjustments.
However, the car can restart after about a minute as the sensors intermittently provide correct data to the ECM.
Diagnosing and Fixing the Problem
- The best way to diagnose sensor issues is to check for trouble codes using an OBD-11 scanner. In the case of a bad MAF sensor, you can get error code P0101.
- If the camshaft position sensor has problems, the error code will be P0340. On the other hand, the trouble code for a bad crankshaft position sensor P0335.
If the MAF sensor is faulty, you can clean it using any electronic contact cleaner. If this does not fix the problem, you must replace the faulty sensor. Replacing the MAF sensor involves the following:
- Step 1: Disconnect the battery’s negative terminal.
- Step 2: Locate the sensor between the air filter housing and the throttle body.
- Step 3: Unhook the wiring harness from the sensor.
- Step 4: Remove the faulty sensor by unscrewing any clamps holding it in place.
- Step 5: Install the new sensor in reverse order and clear any error codes.
The above steps also apply when replacing the camshaft sensor, and the only difference is the sensor’s location. You can find it on the cylinder head, at the timing cover, or on the side of the engine block.
Below is a video of how to perform a camshaft sensor replacement:
As for the crankshaft sensor, you should let a qualified technician perform the replacement. The reason is corrosion around it can make the job difficult.
3. Vacuum System Leak
Your vehicle’s vacuum system plays a role in regulating the air-fuel mixture entering the engine. If you have a leak in the system, the engine will receive too much air and not enough fuel.
Consequently, your car will die but restart when you turn the ignition back on. This happens especially when the leak is minimal, causing it to stop temporarily.
Diagnosing and Fixing the Problem
- Look for a disconnected or loose rubber hose connection in your vacuum system.
- Also, check the intake manifold gasket for cracks.
Once you have located the source of the vacuum leak, you can fix the problem by:
- Replacing the intake manifold gasket
- Reconnecting unplugged vacuum hoses
- Tighten loose hose connections
If you lack strong DIY skills, you should not attempt to do the gasket replacement yourself. The job is very time-consuming.
4. Overheating Problems
A car can die in the middle of the road and then restart due to overheating issues. These problems can result from a coolant leak, defective thermostat, cracked radiator, and low engine oil.
When the engine overheats, it will temporarily lose power, causing the vehicle to shut off. And once the engine has cooled down, your car will restart.
Diagnosing and Fixing the Problem
- First, check for coolant leaks underneath your car while it is idling, which could be caused by a cracked radiator or hose.
- Next, remove the thermostat from its housing and put it in boiling water (over 200 degrees Fahrenheit). If it does not open when submerged and close after pulling it out, it is faulty.
- If your vehicle has low engine oil, the oil light should illuminate your dashboard.
Once you have determined the cause of the overheating issues, your mechanic should:
- Replace the faulty cooling system components.
- Top up the coolant.
- Refill the engine oil.
5. Ignition System Issues
Faulty ignition coils are the common ignition system issues that can make your vehicle shut off while driving and then restart. Ignition coils produce the high voltage required to fire spark plugs and keep the vehicle moving.
If the coils are failing, they can lead to incomplete combustion. As a result, your car will feel sluggish and then die due to loss of power. However, the coils’ operation could improve after some time, allowing you to restart the car.
Diagnosing and Fixing the Problem
Remove the coils and inspect each for cracks or damage. If damaged, replace them through the following steps:
- Step 1: Disconnect the battery.
- Step 2: Locate the coils in the engine bay.
- Step 3: Unhook the electrical connector from the coils.
FAQs
Below, we will respond to frequently asked questions about a car dying while driving but still having the power to restart.
Is it safe to drive a car that shuts off while driving and restarts?
No. Driving a car with such a problem can pose a significant risk to you and other road users. Therefore, you should avoid it and have the issue fixed immediately.
Can a bad alternator cause my car to die and restart while driving?
No. A bad alternator will only make your car shut off but not restart while driving. The reason is that it will not recharge the battery. Therefore, the only way to restart the car is to jump-start it.
What causes a car to die while driving and restart but no check engine light?
Generally, fuel delivery issues, such as a faulty fuel pump and dirty filter will not cause the engine light to come on. This happens when the problem is intermittent, and the engine restarts immediately.
Conclusion
Having your car die while driving and restarting can be a nerve-wracking experience, even for an experienced hobbyist mechanic. The good news? If you know the different causes of the problem, diagnosing and fixing it should be easy. However, if you lack basic mechanic skills, you should seek help from a professional mechanic. The reason is that some repair jobs can be complex, and you could end up causing more damage to your car.