Why wont my car start but I have power?

If your car has power but won’t start, it can be especially frustrating. The lights come on, the stereo comes to life – but your engine just won’t crank.

So, what’s the problem?

In truth, there could be any number of things wrong. With this in mind, we’ve put together a quick guide that will help you understand what’s going on under the bonnet!

When you’ve read this guide, you’ll have a better understanding of what could go wrong – and how Auto Hero can help!

What’s going on when the car won’t start?

Your car’s engine needs very specific conditions to start when you turn the ignition switch. It needs exactly the right amount of fuel and air, a source of ignition from the spark plugs, help from a starter motor, and a handful of other factors to be all working properly.

If the car’s electrical system is good, the engine will have some of the conditions it needs – but with one missing, it still won’t come to life.

So, what could those missing conditions be?

1. The battery could be flat

This is the most common reason why a car have power but won’t start. If your headlights are dim or your car is making a clicking sound when you turn the key, it’s likely that your battery is flat.

You can check this by using a multimeter to test the voltage of your battery. If it’s 12.6 volts or less, then it’s time to recharge or replace your dead battery.

2. There could be an issue with your starter motor

If your starter motor is faulty, it won’t be able to provide the power needed to start your engine. This can be caused by a number of things including a loose wire or a problem with the solenoid. Engine cranks needs a lot of power to get started – so if you have a faulty starter motor, your car won’t turn on.

You’ll need to get this checked out by a mechanic to see if it needs to be repaired or replaced.

3. Your fuel system could be the problem

If your car has petrol in the tank but won’t start, there could be an issue with your fuel system.

This fuel supply system is made up of a fuel tank, a fuel line or fuel lines, a fuel pump, fuel filter, and a fuel injector on each of the engine’s cylinders.

It could be something as simple as a dirty air filter preventing enough air from getting into the engine or a problem with the fuel pump not delivering enough petrol to the engine. Again, this is something best left to a mechanic to diagnose and fix.

4. You battery terminals may be corroded

If you don’t have a dead car battery but you still don’t seem to be getting full electrical power to get your engine cranking, you might have corroded terminals on your battery.

The acid inside your battery can cause a reaction that creates a kind of ‘fur’ build up on the terminals. This reduces the effectiveness of the connection and can causing problems with electrical power delivery.

Sometimes, cleaning the terminals with a wire brush and reattaching the cables can fix a problem like this – but be sure to wear appropriate protective clothing if you do this job.

5. Your battery cables could be loose

Battery cables should connect tightly to the battery terminals. If they don’t, you could have no power or intermittent power – and this often won’t be enough to ensure the car cranks.

Battery terminal clamps are quite simply to tighten up – so if they seem loose, you might find your problem is solved with a few careful turns of a 10mm spanner.

Car still not starting?

These are just some of the reasons why your car might have power but won’t start. If you’re having trouble with your car, it’s always best to take it to a mechanic so they can figure out what’s going on and fix it for you. Trying to carry out bigger fixes yourself might just make things worse!

If you need the help of a local mechanic – Auto Hero can help! Give us a few details and we’ll connect you with the best workshops in your area. We even work with mobile mechanics in most areas – so you don’t have to worry about moving your car if it won’t start!

Written By

Matt Banks

Matt is the founder of Autohero.com.au and has been hooked on cars and repairs ever since childhood. A veteran in automotive since leaving school, Matt has completed his trade as a panel beater and is across all things with wheels. 

His first car was a 1967 FORD XR Wagon followed by a string of collectable Holden’s.

Have a question for Matt? leave a comment below.

Auto Repairs Are EXPENSIVE

There are certain signs that your car is dead, won’t turn over, or in the process of dying. By realizing these signs, you can prevent your car from running and functioning as they should. There are certain symptoms, like your engine cranking but the inability to start, your engine doesn't crank, inconsistent starting and stopping, difficulty cold cranking, and repeated car jumping. Any single one of these signs can alert the driver that your car won’t turn over, but has power. 

If your engine cranks or turns over when you put the key in the ignition and turn the key, the most likely culprit is actually a dead battery. Although you have done the tests and determined the battery is not the culprit, most of the time, the battery is the cause of the issue if the engine cranks and makes noises. However, there are some circumstances where the alternator could be the cause of the issue. If you find yourself in this situation, you need to narrow down why your car won’t turn over but has power.  

To determine why your car won’t turn over but has power, you need to disconnect the cable from your engine and let the engine run for 30 minutes to see if the alternator can charge the battery and power the car. If the alternator and the battery are working in good condition and functioning as they should, you need to troubleshoot and diagnose the other potential root causes of the problem. 

If your engine doesn't crank, you can’t start your car, and there are no lights or electric powered devices working, then your battery may or may not be at fault for why your car won’t turn over but has power. As you know, the battery is in charge of powering all electrical accessories in your car if the alternator is not running.

However, if you realize that your car battery is working well but your car won’t turn over, then the culprit could actually be a combination problem with the alternator. If the car does not crank or turn over, but the headlights turn on, this could be due to an alternator issue, mechanical problem, or engine deterioration. If this is the case, your battery might not be the reason behind why your car won’t turn over but has power. 

If starting is a problem for you regularly, this is a clear sign that your battery terminals are corroded, damaged, broken, or loose. If your connections are not secure and snug, then your power is being drained consistently by some gadget that causes a quick decrease in power. If this is the case, it can be the culprit as to why your car won’t turn over but has power. 

Check the battery cables first to see for any visible signs of damage. If they look okay and there is no sign of damage, then the problem is not the battery, and the starter could be the cause of why the car won’t turn over but has power. 

This slow-draw of electricity from your system is actually quite common and can drain your car battery if you let it sit for a few days. To investigate these “parasitic” drain of electric power in your vehicle, you need to bring your vehicle to a mechanic to have them use a diagnostic tool and voltmeter to see why your car won’t turn over but has power. 

Cold-cranking functions to give your engine enough energy to get started for the first time after sitting or a long time. This is generally called “cold-cranking,” as it could be cold in the morning when you turn on your car and your engine itself is cold from sitting for so long. 

A sign that your battery is the problem for your dead car is that you have to turn the key a few times in the ignition for it to work, you need to press on the gas pedal repeatedly, and it takes a lot longer to crank. The long cranking and the dead car can be the reason why your car won’t turn over but has power. 

However, the reason could be that your battery is good, but the battery might not be big enough or provide enough power for your vehicle when it was installed. In this case, the mechanic who did the installation got the wrong size battery for your car, causing your car not to turn over but has power. 

If you always have your jumper cables out to start your car due to the inability to start on a consistent basis, this is a sure sign that something is wrong with your vehicle. In this case, you might have finally had enough when you determine why your car won’t turn over but has power – this indicates something is very wrong with the alternator, starter, fuel pump, or electrical components. 

Car Won’t Turn Over Symptoms

Your car might not start for numerous reasons and boil down to various root causes. However, if you are experiencing why your car won’t turn over but has power, this could be due to other causes – like a faulty alternator and not a dead battery. Let’s check out the most common car won’t turn over symptoms and what you can do to troubleshoot these problems.

If you put your key in the ignition and turn the key to hear the audible clicking sound and hear the engine turn over and it doesn’t happen, this can make you immediately concerned. If this is the case, check the new battery terminal cable connections to see if there are any loose wiring connections or damage. If it starts when you turn on the engine, you might need to check the new battery cables. 

When you are trying to figure out why your car won’t turn over but has power, the alternator could be the culprit. 

If you realize why your car won’t turn over but has power, this could be due to an improper battery installation in your car from the last person to work on your vehicle – your mechanic. In rare circumstances, mechanics may install a dead battery in your car during a replacement and cause your car to make a clicking noise and not be able to start.

If you realize that you have just replaced your battery, but it still doesn't work, you could be trying to figure out why your car won’t turn over but has power. 

If you hear noises, but your car still won’t start, you need to check the fuel supply to your engine by analyzing the fuel filter, the fuel lines, and the fuel injector to ensure they are all working properly and do not have any holes, leaks, damage, or cracks. 

If all fuel and fuel system components are in good condition, check the spark plugs and see if they are sending the necessary electrical sparks and timing to your ignition to spur the internal combustion. If the spark plugs are not working correctly, you might feel your car cranking but cannot turn over the engine or start the vehicle.

If you hear cranking, but your car won’t turn over but has power, this could be signaled by loud cranking. 

If you use a car that has a carburetor, then check the choke to see if it is closing and opening at the right intervals. If you have fuel injection, you can’t make this diagnosis on your own and will have to bring your car to a mechanic to see why you are having trouble starting your vehicle. If you realize that your engine starts but dies much sooner than it should and does not provide any performance benefits, you might find out why your car won’t turn over but has power. 

If your car won’t start but has power, only occurs in certain conditions; this could be due to excess dampness inside the vehicle. Bring your car to a local auto body shop and ask the mechanic to check the distributor cap inside for any wetness or dampness. The mechanic needs to see if the moisture has harmed the internal components. 

If this is the case, try to get rid of the dampness by evaporating it inside the cap using an aerosol can of a solvent. Using the aerosol can remove the moisture and prevent your car from not being able to turn over. 

Conclusion

When looking at why your car won’t turn over but has power, you need to keep an eye on the main internal components in your vehicle, like the engine, transmission, and battery!