Car Won’t Turn Over But Has Power

Car Won’t Turn Over But Has Power – How To Troubleshoot

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.

Car Won’t Turn Over But Has Power – Why Does This Happen?

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.

What Are The Things That Can Go Wrong?

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 poking his key in and cranking 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.

1. Battery And Ignition System

Car Won’t Turn Over But Has Power

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.

A Dead Battery: An Unlikely Issue For A Car That Won’t Turn Over But Has Power

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, 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.

If you have a multimeter, check the battery voltage and it should be more than 12 volts. Change your battery if it reads less than 12 volts and you should be good to go.

Malfunctioning 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.

If there is no recharging happening, the electrical systems in the car will take the power from the battery. This can eventually drain all the juice from the battery, rendering it dead. For starting an engine, the starter motor needs a large bout of electricity from the battery. In this case, there is nothing left for the battery to give. The car won’t start but has power.

Checking the alternator is a simple task. Jumpstart the vehicle and use a multimeter to measure the voltage at the battery terminals. If it is less than 12 volts, the battery may be dead. 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. This diagnosis can only be done by a trained mechanic. Replacement of the alternator is also not a rookie’s job so you will benefit from a trip to a garage.

Issues With The Starter Motor

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.

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.

2. Fuel System

The fuel system is what feeds the engine its 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 is found to be faultless. Let us drill through the list to find out what can be the pain points in the fuel system.

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.

Low Fuel Pressure/Clogged Fuel Lines Or Fuel Rail

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.

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.

You can check the fuel injectors yourself. Press a screwdriver onto each of them and listen for a click as the engine cranks. If there is a click, that fuel injector is properly functioning.

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.

Generally, it is a good practice to clean your fuel system as a maintenance procedure. This story will help you as a guide to learn how.

3. Air Intake System

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.

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.

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.

4. Spark Ignition system (For Gasoline Engines)

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?

Troubles With 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.

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. Watch this video to learn how to do this.

Which Issue Is To Be Expected The Most If Your New Car Won’t Turn Over But Has Power

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, 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: What Is The Fix?

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 the 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.

1 Comment

  • trish Says

    my g6 pontiac wont start at times till i run the gear shift through the the gears and it will start it might take 2 or 3 times to do this has anyone got any ideas on why it happens i have replaced everything that could be the problem and it still happens at times

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