This is easily one of the biggest nightmares for any car owner. Cranking your vehicle one fine morning only to find out that the car won’t turn over but has power. It can be frustrating and disappointing, but with the right guide, troubleshooting is easy. Read on to find out.
If a car won’t turn over but has power, it is failing to fulfill the one task that it is made to do, take you places. The engine refusing to start up can be scary, but it may not always be a nightmare to fix. In fact, in most cases, it ends up being an easy fix. Before we delve into the details, let us learn more about the conditions that happen so that your car won’t turn but has power.
When anything goes wrong with an engine, the first order of business is to assess the situation. Most problems cannot be narrowed down by looking at the health and age of the car. For example, if your car is just a year old, it is highly unlikely that it has a fuel injection issue. In newer cars, it’s most likely a faulty battery.
In older cars, however, especially the ones that are being started after a long while, it can be anything. Right from the battery, all the way to the engine itself. But let us not panic and break it down piece by piece to understand why it happens and how it can be cleared.
Why Won’t My Car Start
If your car won’t start but has power, anything from the battery to the engine can be the culprit. But this is not hard to track. We just need a map of events that happen when you try to start an engine.
To understand what can go wrong with an engine, let us look at what happens when you crank it. The first thing any driver does after sitting in a car is poke their key in and crank the engine.
Then the charge from the battery runs to the starter motor that rotates the crankshaft. Meanwhile, fuel from the fuel tank is pumped into the engine through the fuel pump, then through the fuel lines, the fuel rail, and finally the injectors.
Simultaneously air gets sucked in through the air filter and enters the engine after passing through the intake manifold. In the case of a gasoline engine, a distributor sends sparks through the spark plugs into the engine. This ignites the air-fuel mixture and voila, there is your horsepower.
With the operations sorted, let us dive into each stage and see what can go wrong in each of them.
Car Won’t Turn Over But Has Power, Possible Causes #1: Electrical
This is easily the most probable issue a car that won’t start but has power will have. A flat battery is not an uncommon sight. Almost all car users must have experienced the trouble it can bring.
Though it is just a matter of replacing the battery – a 5 min job – the headache a failed battery can bring is agonizing. But the battery is not the only thing that can go wrong at this stage. But let us start with the most obvious.
1. Dead Car Battery
If your car won’t start but has power, the first thing to know is that it is not a dead battery. That may make the title of this story seem counterproductive but let me explain. If your car won’t turn over but has power, with all electricals functioning, it certainly is not a dead battery.
A car with a dead battery will not have any of its electricals functioning in the worst case. If they function, their weakness will be evident. The lights will be completely dim, the horn will not sound okay et cetera.
In this case, the age of the battery needs to be considered. If you have a new battery, it is not likely to fail this easily. But if your battery age is more than 4 years, it may be almost time to take it to the grave.
If your vehicle has not been used for a while, jump-start it, and drive it for a while. After a drive, the battery should be charged, and restarting it should be a breeze if the battery is good. If not, proceed to the next step.
2. Bad Alternator
The alternator is the device that takes power from the engine and recharges the battery when the vehicle runs. It is essential for the electrical cycle of a car as its malfunction can stop the car from starting. If the alternator is unable to charge the battery, it can exhaust its stored energy and die.
But the main event we are expecting is an increase in the voltage when you rev the engine. The alternator, if good, should flow a bunch of electrons into the battery as the engine runs. If no change or a meek increase in voltage is detected, it shows that the alternator is failing to do its job.
The alternator can have issues with its coil, which converts the rotational motion from the engine into alternating current. Or it can be an issue with the Rectifier/Stator which converts this alternating current to direct current.
3. Bad Starter
This is the third and final element in the ignition circuit. The starter motor is directly connected to the crankshaft of the engine. This rotates the crankshaft to initiate its strokes of the engine when we turn the key. A failure of the starter motor can be a reason why your car won’t start but has power.
Diagnosing this issue is quite simple. If you turn the key, it should crank. The cranking of the engine is initiated by the starter motor. So, if the starter motor has gone south, you turning the key will make no difference. No cranking, no desperate attempts to get the cylinders firing. Just silence.
To confirm that it is indeed a starter motor issue, you can diagnose a dead battery or alternator. If these are working, and the engine won’t crank at all, the starter motor is most likely your culprit.
If you have a stick shift, you can push start it, but that is a solid workout that we will not recommend due to safety reasons. So, tow it to the nearest garage and get the faulty starter motor replaced.
4. Fuse And Wiring Issues
This is a little too obvious. Before your jump the gun and replace the alternators, starter motor, and battery in one go, check the fuse box. If the ignition fuses are blown, a simple fuse replacement can get your car started. Be sure to diagnose what caused the fuse to blow in the first place.
The wiring harness can cause issues too. Do you have a rodent issue in your area? If yes, they may be the reason you are standing in your driveway, late for work, and with a dead car. These mincing machines can make quick work of a car’s wires, disconnecting many critical components.
The starter motor and battery may be perfectly healthy, but a severed connection can render them useless. A cut-open wire can cause electrical shorts that can blow the fuse, or more importantly, turn into a fire hazard. So, be sure to check and make sure that no wires are damaged. A mechanic can help you with that.
Car Won’t Turn Over But Has Power, Possible Causes #2: Fuel System
The fuel system is what feeds the engine it’s choice of potion. Gasoline and diesel engines have different designs for their fuel systems, but the general working principle is almost the same.
So, if your car won’t start but has power, the fuel system can be a source of the problem. But the fuel system must be checked after the entire battery & ignition system are found to be faultless. Let us drill through the list to find out what can be the pain points in the fuel system.
5. Faulty Fuel Pump
This is not a problem with most new cars. If your car is regularly driven and is filled with neat gas/diesel, this should not bother you. Unless your vehicle was fitted with a faulty fuel pump right from the factory. But, if your car is quite old or the fuel quality in your area is questionable, a faulty pump can be a scary reality.
Diagnosing this problem is quite easy. When you turn your key to ignition, before cranking the engine, you can hear a hum from the rear. This is the functioning of the fuel pump. Before the car is started, the fuel pump ensures the flow of fuel and readies it for injection.
But if you have a faulty fuel pump, this may not happen. The engine will not get its calories and refuse to start. So, when you turn the key and hear no hum coming from the back, it is possibly a fuel pump issue. Or your car’s sound deadening is that darn good. You decide.
But if you suspect a fuel pump failure, it must be checked. Maybe it is just clogged up and unable to function. But that is for a trained eye to decide. So, an expert technician is needed for this job.
6. Low Fuel Pressure
Your fuel pump may be working but what if the fuel pressure is not reaching the injectors? A clogged fuel rail or fuel line can be an issue. Or it can be a fuel pump issue that reduces the fuel pressure. Some fuel rails may have a Schrader valve on the fuel rail that helps you test the fuel pressure.
If the fuel pressure is found to be low, you have to give it to a mechanic for further diagnosis. But know that, these issues mostly crop up in very old vehicles.
7. Fuel Injector Failure
This is a rare possibility if your car won’t start but has power. If you have a four-cylinder engine, all four fuel injectors should stop working for the engine to not start. So, this is a rare scenario but still possible.
If you find all your fuel injectors failed, proceed on to check the throttle position sensor. Remove the sensor and try starting the engine. If it starts, replace your throttle position sensor and you should be on the road in no time.
Car Won’t Turn Over But Has Power, Possible Causes #3: Air Intake
This is yet another rare that prevents a car from starting. If your car won’t start but has power, it can mean that the engine is not getting all it needs. We covered the starting movement and fuel supply. Now let us focus on the air supply. The engine needs air to burn the fuel. If less air is being pumped in, your car won’t start but has power.
8. Clogged Air Filter
In rare instances, a clogged air filter or airline can stop the engine from starting. Check for a choked filter. Replace the filter if needed. Look as far as possible into the air tube that leads to the engine to spot any debris, animal nests, etc. If it looks clear, it is clear.
9. Faulty MAP Sensor Or MAF Sensor
The MAP (manifold absolute pressure) sensor and MAF (mass airflow sensor) measure the volume and pressure of the air being pumped into the engine. If these sensors are faulty, the engine can get a wrong reading and will not start. Unplug these sensors and start the engine. If it starts, replace the faulty sensors.
Car Won’t Turn Over But Has Power, Possible Causes #4: Ignition
For diesel engine owners, you can skip this section. Gasoline engine users, read on. If your car won’t start but has power, and has a gasoline engine, it can be a spark issue. The system is important for spark-ignited units like gasoline or natural gas engines. So, what can go wrong in this area?
10. Ignition Coil Or Distributor
The ignition coil and the distributor are two important parts of the ignition system. If they have failed, the engine will not receive timely sparks, causing it to not start. You can test these using a multimeter but a trained hand working on it will be the better option.
11. Faulty Spark Plugs
Spark plugs ignite the fuel injected into each cylinder. These can wear down over time, leaving the engine with no spark to burn fuel, and your car won’t start but has power.
Removing the spark plugs is easy. Once removed the spark plugs can be inspected for cracks or clogs. If the ceramic area of the spark plug is cracked, the insulation is compromised, and it is a broken spark plug. If the tip of the plug is clogged with gunk or debris, you must replace it.
Replacing spark plugs is supposed to be done as a timely maintenance procedure. Keeping tabs on their health and replacing them at manufacturer-recommended intervals can help sustain the health of the engine.
Once you have the spark plugs out and they look okay, you can test them again using a multimeter. This measures the resistance across the ends of the spark plug. If it shows a wrong resistance across the ends, it is a faulty plug. If it shows resistance between any two points, other than the ends, it is still a faulty plug.
Car Won’t Turn Over But Has Power: What Can Cause A Car Not To Start
The battery is mostly the culprit for a new engine that fails to start. But if the vehicle still has power, a dead battery is mostly out of the question, and so is a dead alternator. Some batteries may come with lower charge retention capacity from the factory. This is a manufacturing defect and a replacement can be claimed under warranty.
But if a car won’t start but has power, it is easy to confuse that the battery is completely healthy. Especially, if the lights, horn, and other electricals function properly, it can be quite misleading. This is due to the fact that all peripherals do not have the same energy requirement.
But the starter motor needs a lot of energy to crank the engine. A battery that is almost at the end of its lifecycle may not be able to supply enough electricity to the starter motor. Some electronic ignition systems also will leech a lot of energy at the start. But the peripherals like lights, horns, stereo, etc. may work as they need less energy from the battery.
This is where it can confuse everyone. So, if your car won’t start but has power, break out your multimeter and get the battery terminals checked. With the engine off, it should read ideally 12 volts, if not very close to it. If not, the battery is almost dying.
Jumpstart the engine, turn on most peripherals and read it again. There should not be a drop in voltage, and it should increase to 13.5 to 14 volts as you step on the accelerator. If this is not happening, then it may be an alternator issue. This is the most common issue if a car won’t start but has power.
Car Won’t Turn Over But Has Power: How To Fix It
If the issue can be traced back to a faulty battery or alternator, replacing them is the only measure. This diagnosis can be done by almost anyone and needs no specialized tools. You only need to have an inexpensive multimeter.
But if the problem lies with other areas of the engine like the fuel system, ignition system, or air intake, you will need a trained mechanic to go to the bottom of it. Yes, the basic diagnosis can help you narrow down the options. But, for a thorough diagnosis, a skilled pair of hands is indispensable.
But that being said, the preliminary diagnosis must be done before you approach a garage. This is more important if you are approaching an unknown mechanic. There are possibilities of them scamming unwary customers.
So, if you turn up at an unknown garage and go “There is something wrong with my engine”, they may pick that up as an opportunity to drain your wallet. Though you might find that your car insurance policy will cover assistance to get your car started and back on the road, it’s worth checking with them. So, do your homework and conduct basic troubleshooting to narrow down the possibilities.
It is always better to tell a mechanic that “I suspect it is a problem with my fuel pump. Can you please check that for me?” instead of being completely clueless. Not rocket science but can save you some valuable bucks.
FAQs On Car Won’t Turn Over But Has Power
If you’re still curious to learn more about why your car won’t turn over but has power, our FAQs here might help…
How To Start A Car With A Bad Starter
If your car fails to start properly due to a bad starter, there are some things that you can do. First off, check to make sure that all the wires leading to and from your car’s starter are in good shape. And, the respective connectors are all tight and secure. Besides this, you could also try tapping on the starter very gently with a hammer. Over time, it’s possible that the armature inside isn’t making good contact with the starter motor’s brushes. To close that gap, a gentle tap with a hammer can make them fall into place neatly once more. Other than this, you could try bypassing a bad starter relay by jumping the (starter) motor’s positive terminal to the (starter) solenoid’s terminal.
How To Tell If Alternator Is Bad
There are numerous ways that you can tell if your car’s alternator is failing. The most obvious one would be a dead or dying battery, as the now-faulty alternator isn’t able to provide a sufficient amount of charge. Elsewhere, a bad alternator would also impact your car’s electrics and their ability to function. So, see if you’re able to notice dim or overly bright lights, or if the accessories (like the radio, A/C, power windows, heated seats, etc.) aren’t working properly. Beyond this, your car would also have trouble trying to start. It might fail to turn over, show a battery warning light, emit burning smells, make growing/whining noises, or cause your car to stall while driving.
How To Test A Car Battery
To test your car’s 12V battery, you should start by turning off the ignition and all other accessories or electronics. Then, grab a multimeter… And, if the multimeter isn’t able to auto-range, manually set it to 20V DC. Now, connect the red lead to the positive battery terminal, and the black lead to the negative battery terminal. Finally, take a look at the multimeter’s readings. An ideal reading should be somewhere between 12.2 volts to 12.6 volts. If the reading is below 12.2 volts, it’s an indicator that your car’s battery is weak or dying, and needs a recharge. It’s a good opportunity to consider replacing the battery if it’s too old (more than 3 to 5 years), as well.
Why Is My Battery Light On
Some cars will display a battery light warning on the dashboard if it senses a problem with your vehicle’s electrical system. Specifically, it usually entails a dying or bad battery. Or, if there’s an issue with your car’s alternator, including if there’s a bad alternator belt (or if the entire alternator is faulty). Otherwise, corrosion on the battery terminals, frayed/burnt battery cable, or general wiring issues may also prompt the battery light to come on. In some cases, it’ll light up if the car senses a likely accessory overload. This is where your car’s accessories and electronics (radios, lights, infotainment system, etc.) are drawing too much power at once.
What Sensors Can Cause A Car Not To Start
Should your car fail to start, among the potential causes is faulty sensors. There are a vast number of sensors that might prevent your car from starting. They might relate to informing the ECU of the state of the engine, such as the crankshaft position sensor and camshaft position sensor. Or, it might be sensors that otherwise fail to initiate the combustion process (i.e. mixing and ignition of fuel and air), such as the fuel pressure sensor, manifold absolute pressure sensor, or mass airflow sensor. Otherwise, the trottle position sensor, brake pedal position sensor, and oil pressure sensor are among the other possible points of failure as far as sensors are concerned.
These tools have been tried and tested by our team, they are ideal for fixing your car at home.