Welcome to our indepth article focused on answering all of your car starter problem questions, such as : How to start a car with a bad starter, what causes a starter to go bad, can jump start a car with a bad starter and much more.
✓ Quick Tip : If your car won’t start and suspect it’s your starter, get a hammer and gently tap it 1 to 3 times. This has worked for many countless times but if your starter is completely gone then this probably won’t work. Either way, it’s worth trying and has allowed me to get my car started so I can drive it to a shop and have the starter replaced.
How to start a car with a bad starter
There are few things more annoying than a car that won’t start. When you’re in rush to get to that urgent meeting, this is more than just an inconvenience. If you want to know how to start a car with a bad starter, I have a few useful tips that can save you a lot of hassle.
Before I get into the nitty gritty of how to start a car with a bad starter, let’s cover the basics. Knowing what a starter is, and how it works, is going to help you diagnose possible starter issues and the advice on how to start a car with a bad starter will make better sense if you know what we’re talking about.
What is a car starter and how does it work?
The starter on your car consists of three basic components and all need to work properly in order to start your car. The electric motor is the primary component, this is what spins the engine. In order to do this, the starter needs a gear that engages the flywheel. As the starter motor starts to turn, it moves a gear forward. This is an important part of the process and a gear failure might cause the car not to start. The final important component is the solenoid, this an electric contactor that acts as a switch to conduct electricity from the battery to the starter.
VIDEO | How A Car Starter Works (Classic Video)
These are the basics. Now let’s take a look at how a starter works, by taking a look at each of these three components in more detail and how they function as one unit.
An internal combustion engines works by causing an explosion (combustion) inside a sealed combustion chamber. Thereby, forcing a piston to move inside the cylinder. The movement of the piston is what drives the whole process by turning the crankshaft. As the crankshaft turns, it controls valves that open and close to allow gas and air into the chamber and the burnt (exhaust) gasses to escape. So, in order for the combustion process to commence, the crankshaft needs to turn.
In the early days, people had to use a crank handle to manually spin the crankshaft. This is how they got the engine to fire up. It didn’t take long before someone figured it would be a good idea to fit a large battery to the car and this can be used to power an electric motor that will spin the crankshaft.
What we need realize from the offset, is that the electric motor that spins your engine needs to be very powerful and requires a lot of amps. In other words, it uses a lot of electricity. A small compact car may only need around 30A, larger engines can use 100A or more. Diesel engines have high compression engines and these starter motors can be as high as 300A for large diesel engines.
This high amperage is an important consideration and will feature when we discuss the tips on how to start a car with a bad starter. High amps require thick cables and high amperage switches. So, the power needed to turn your starter motor cannot be conducted through a key switch with thin wiring. Yet, when you turn your key, the car starts. How does this work?
Depending on the size of the engine, and where the battery is located, a battery cable can be anything from 2 – 8 gauge, large diesel trucks may even use a 1-gauge starter cable. This cable runs directly from the battery to the starter, modern cars will have a fuse to protect the wiring and battery from a short circuit. The switch that connects this current needs to be equally up to the task. This switch is known as a solenoid. A higher gauge (thinner) cable is connected to the key switch inside your car. When you turn the key to start your car, power is sent to the solenoid. This energizes an electromagnet that pulls in a contactor. This contactor closes the circuit between the battery cable and the starter motor, causing it to spin.
The starter motor is connected to a shaft with a gear at the end of it. This gear turns forward, by means of a Bendix, as the starter motor begins to spin. Once the gear is pushed all the way forward, it engages the flywheel, which is connected to the crankshaft of the engine. The flywheel has a large ring gear with teeth that slot into those of the starter gear. When the two are engaged, the starter spins the engine and begins the combustion process.
If any of these functions don’t happen as they should, the engine may not start. Your battery is an important part of the equation, as are all the connections between the starter and the battery.
Starter or Battery? Is your battery the cause?
More often than not, a weak battery is the reason why your car won’t start. There are often telltale signs of a weak battery. The starter may begin to turn and then slow down, you will hear the starter make a droning noise if this is the case. The solenoid may engage and disengage in rapid succession. You will hear a rapid clicking sound if this happens. You may simply hear nothing but a single click when the battery is completely flat.
A quick test to see if the battery is functioning properly is to honk the horn or turn on the windshield wipers. If the horn makes a dull sound, or the wipers move slowly, the battery isn’t providing the voltage required to start your car.
If your battery is the cause, you’ll need to use jumpers to start your car. If the battery is fine, you need to consider the starter, or the electrical connections to the starter, as being the root cause of your starting problem.
How to start a car with a bad starter
Having eliminated the battery as the reason for your car not starting, you need to move on to the starter. It may be a bad starter or the condition of the wiring.
Start by checking the connections to the starter. Tighten these, just to be sure. A loose connection is the most common cause of a bad starter.
Corrosion is also a common problem. Dirt, grease, or rust can easily cause a weak current to the starter. If you notice that your starter wiring is covered in grease and dirt, or has a brown rusted appearance, you’ll need to clean the connections. You will need to disconnect all the cables from your starter and use sandpaper to clean up the terminals until the regain their shiny appearance. For a quick fix, you can simply buy a can of contact spray which will clean the contacts. Though, cleaning with sandpaper is the best long term solution.
Older cars may need replacement terminal cables. The thick red cable that is bolted to your starter is what supplies the power to turn the motor. You can trace this cable back from the starter to the source and disconnect both ends. Replace this with a cable of the same gauge and length. If you can’t match the gauge correctly, you can always use a thicker cable. But never use a cable that is thinner than the original one fitted to your car. This takes care of the positive supply to your starter, but the negative supply is equally important.
The negative terminal of your battery will usually be connected to the body of the car and the engine. It’s advisable to change both these cables on an old car. Again, use the same gauge, or thicker cable, as the original. Even then, this may not be sufficient. Your starter receives a negative current by the conductivity through the engine block. Over the years, corrosion, oil buildup and dirt collecting around the engine causes a weak negative connection to the starter. It is impossible to clean all of this away, as some of it is internal. The solution is install an additional negative cable to the starter.
Remove one of the bolts that attach the starter to the engine. Use the same gauge cable as the one connected to the negative terminal of your battery. Place the mounting bolt for your starter through the lug at one end of the cable, and refasten it. Now loosen one of the bolts that mount your alternator to the engine and place it through the lug on opposite end of the cable. Refit the alternator bolt. This ensures a good negative supply to the starter. Take note that his is only necessary for older cars where the engine block is resisting the current flow for the negative connection to the starter.
Okay, so all the electrical wiring is in order, and still no luck. It’s not time to give up just yet. The solenoid or starter gear may be jammed. This is often as a result of dirt inside the starter. Using a wrench or hammer, tap on the back of the starter a few times. This will loosen the gear or solenoid. Though this is a sign that the starter may need a repair job. So, even if your car starts after giving the starter a few knocks, the problem is most probably going to reoccur. The starter will need to be stripped and cleaned, to permanently resolve the situation.
If you hear a grinding sound when you try start your car, you can safely assume that the Bendix is faulty. This is the mechanism that pushes the starter gear forward so that it engages the flywheel. In some cases, removing the starter and cleaning the Bendix can help. Though replacing the Bendix is usually the only, or best option.
Can you jump start a car with a bad starter?
Generally speaking, I’d say no – you can’t jump start a car with a bad starter. Jumper cables or boosters are used when the battery has no power. You’re basically using a second battery to supply the power needed to start the car.
However, if the cause of the problem is as a result of a bad connection to the starter, connecting a jumper directly to the starter can be a solution. So, instead of connecting the jumper cable to the battery of the car that won’t start, you connect it to the positive terminal of the starter. If the solenoid is not receiving power from the ignition key inside the car, you can use a screwdriver to bridge the connection between the main battery lead, with a jumper cable attached, and the terminal at the back of the solenoid.
Some people may confuse a bump (or push) start with a jump start. A manual car, with a stick shift, can be started in this way. You can turn the ignition key to the on position, the warning lights on your dashboard will ignite. Put in car in gear, second or third gear is usually better. Keep the clutch depressed while a second person pushes the car to get it rolling. Once the car is in motion, release the clutch. The car will probably shudder a little before the engine fires up. It may take a few attempts before the car starts. If you don’t succeed at first, allow the car to gain a little more momentum before releasing the clutch.
What causes a starter to go bad?
For the most part, a starter deteriorates over time. So the cause of a bad starter is usually old age. The windings on the stator and rotor become brittle and the insulation cracks. Dirt in the starter and general wear and tear may cause the solenoid or Bendix gear to jam.
Starters can fail prematurely from overheating. This happens when you continuously try to start a car that won’t start. A starter is only designed to turn for short while. Cranking the engine for longer than a few seconds, generates a lot of heat. Similarly, holding the key in the start position for a second or two and then trying again several times in short succession will also overheat the starter.
If your car won’t start after two or three attempts, there is obviously a problem with fuel or ignition system and this needs to be rectified. Cranking the starter motor won’t help to start an engine if there is mechanical or electrical failure.
What are the signs of a bad starter?
If you hear that your starter is turning slower than usual, this an obvious sign that either your battery or starter is beginning to fail. A starter that is functioning properly makes a high pitched whine. A starter that is turning slowly, will make a low pitched drone. First have your battery checked to eliminate this as the cause. If the battery is fine, you can try the tips listed above for starting a car with a bad starter. Though it’s probably time to repair or replace the starter.
The starter may turn for a while and then stop. If you try again, it might start. This indicates that the solenoid is probably beginning to fail. It probably means that worse trouble is to come and repairs are imminent.
The Bendix may be showing early signs of decay. Sometimes you may hear the starter gear grinding against the flywheel. This is an unmistakable sound. This can be a result of a bad connection that causes the starter to stop intermittently, causing the Bendix to not fully engage with the ring gear. This can be rectified by checking, cleaning, or replacing the wiring to the starter. It can also be an indication grease and dirt are impairing the Bendix operation, or that the Bendix need replacing. In this instance, you’ll need to remove the starter to resolve the problem.
How much is a starter? Starter replacement cost
I’m always hesitant to talk about the price of automotive replacement parts, because they vary so greatly. When it comes to your car’s starter, you have several options. The most expensive choice is obviously to take your car to the dealership and have them fit a genuine replacement starter. For a small, cheaper car, this is likely to cost you anything from $350 – $500. A large expensive car is probably going to cost $1000 or more.
Having a factory rebuilt starter can save you about 20 – 30% of the cost, when compared to buying a new starter. However, a starter is made to be repaired and this isn’t too complicated if you know what you’re doing. Any reputable mechanic or auto electrical shop should be able to repair a bad starter. This could cost anything from as little as $150 up to around $800, depending on the vehicle and the repairs that are required.
Should I rebuild my starter or buy a new one?
As I mentioned in the previous paragraph, repairing your starter is the most economical option and, to my mind, this makes the most sense.
As a hobby mechanic, I’ve repaired and rebuilt many cars over the course of my life. I find that rebuilding a starter is one of the more pleasurable and rewarding auto repair tasks. The toughest part is removing and refitting the starter. Once you have the starter in your shop you can sit at your bench and work in a clean, comfortable environment. This is an important thing to remember.
Whether you’re doing it yourself, or paying a mechanic, it’s a good idea to do a full rebuild of the starter once you’ve removed it from the vehicle. If you only fix what is broken, you’ll probably have to repair something else not too far down the road. The labor involved in repeatedly removing and replacing your starter is either going to be a waste of money if you’re paying a mechanic, or a waste of your time if you’re doing it yourself.
In my experience, once a starter reaches a certain age, components start to fail. When one part gives up the ghost, the others are likely to follow shortly. So, if you’re going to rebuild your starter, do a proper job of it.
Remove the stator (field windings) and the rotor (armature). Send these to a reputable auto electrical shop for rewinding. Replace the Bendix, bushes, bearing, and solenoid. Clean everything thoroughly and be sure to lubricate the Bendix.
Before refitting the starter, test it several times. Secure the starter in a bench vise and connect it to a battery using jumper cables. Bridge the battery terminal of the starter and solenoid terminal to run the starter motor. Check that the Bendix moves forward and seats against the front bush. Listen to the sound of the motor, you want to hear a high pitched whine. Repeat this procedure four or five times, to make sure that the starter is working properly. I’d recommend replacing the electric cables supplying the starter when refitting. These too will be aging and may not be conducting the full current that is required.