How to start a car with a bad starter

How to start a car with a bad starter

In this article, I explore the best tricks on how to start a car with a bad starter so you can get on your way.

Problems starting are some of the most common mechanical issues we face when maintaining older cars, and it can be a real pain to put up with.

A bad starter motor is one of the most common reasons why your car won’t start.

What is a starter motor?

Gone are the days of hand-cranking your engine to get it to fire, most cars since the 1920s have come equipped with an electric starter to do the hard work for you.

Electric starter motor diagram.
Image credit: https://en.wikipedia.org/wiki/Starter_(engine)

A typical electric starter motor is a cylinder-shaped object connected to the side of the engine. It features a small drive pinion which contacts the much larger starter gear on the outside edge of the engine’s flywheel.

Once the key is turned in the ignition, an electric solenoid is engaged which extends to mesh the drive pinion up with the flywheel gear, and the electric motor turns the flywheel cranking the car over and allowing the engine to fire.

Once the engine has fired the solenoid releases to allow the drive pinion to disengage and the now running engine simply relies on its own inertia to keep turning over.

Bikes are a different story with many featuring a kick start as opposed to an electric start well into the 80s.

Starter Motor Failure Causes

Like most mechanical things, starter motors are subject to lots of stresses and strains and can simply wear out over time.

The parts which are most likely to wear include the electrical solenoid which is susceptible to overheating, the electromagnet inside the starter which also commonly fail due to overheating, or worn teeth on the drive pinion gear which can be a result of loose mountings or just old age.

Luckily, the most common reasons for your bad starter are much easier to spot and fix, quite often for free.

The following tips should be enough to get you to your next destination, which should probably be a mechanic’s workshop.

Check Wiring and Connections

This is by far the most common reason for your car, manual or automatic to have a bad starter. Being so exposed, the wiring for your starter motor can suffer over time and connections need to be repaired or replaced.

Check starter’s electrical connections

First things first, check the electrical connections between the car’s battery and starter motor and ensure they are not loose. A poor connection to the battery can cause an intermittent electrical signal limiting the amps passed on to the starter preventing it from having the strength to turn the flywheel.

I’d recommend giving the connections a wiggle and tightening them up a little anyway.

Once you’ve confirmed that the connections on the battery side are in fine fettle, you can follow the positive wiring from the battery to the starter and ensure that there is no damage to it.

Generally, you’ll find that the positive wire splits off into two, one connected to the car’s alternator and one to the starter motor.

It’s good to keep an eye out for damaged wiring often caused by contacting hot parts of the engine that can short and cause symptoms of a bad starter.

Checking the connections on the starter itself is quite easy on an older car with more space to work in the engine bay. It’s especially easy on a car where the engine is mounted longitudinally (most rear-wheel drive cars with the engine in the front).

Modern classic rear-wheel drive car starter motor.

If your car is front-wheel drive and has a transversely mounted engine, then you may find accessing the starter motor a bit more challenging as it will likely be located in the tight space between the engine and the firewall.

A starter should have three key things, a current from the car’s battery, an earth (or ground connection) and a positive connection to the starter’s solenoid from the starter relay.

Check the Engine’s Grounds

Follow the earth connections, generally, black ground wire earthed to the metal chassis of the car. Ensure that these connections are solid and secure, and not suffering from serious corrosion weakening the connection.

If the ground connection is broken somewhere then it will create an open circuit giving symptoms of a bad or completely failed starter motor.

If you locate a loose ground, then cleaning it up and securing it again could solve your starter problems.

If you find a ground wire that is completely broken, then one handy trick is to rig up a temporary connection between the battery’s negative terminal and the metal body of the starter motor to complete the circuit.

Check the Starter Solenoid’s Wiring

Another common starter wiring problem that’s easy to fix is the solenoid.

If your starter motor is spinning away (and you’ll hear it) when the key is in the ignition but it’s just not cranking the engine over then its quite likely that the solenoid is at fault.

As mentioned earlier, the solenoid extends the drive pinion to the flywheel in order to transmit the turning force of the starter motor to the engine.

The solenoid uses a particularly small wire between it and the main body of the starter motor so check this wiring is in good order and solidly connected first.

If you don’t find a fault here but are still confident it’s a solenoid problem, then the next step would be to try to bypass it.

The solenoid only needs a positive 12v current to engage, so again you can rig up a nice temporary fix in the form of wire directly from the battery’s positive terminal.

When connected you should hear an audible click which is the sound of the pinion drive gear extending to contact the flywheel.

After you hear this, you can simply turn the key and the car will start. But remember to quickly unhook the wire once started so the pinion gear can disengage avoiding unnecessary damage.

Check for Corroded Connections

All the above-mentioned connections are susceptible to corrosion, and it can quite often appear more subtle to the eye.

Corrosion can be a real barrier to good electrical connection and a corroded connection can give very poor conductivity leading to all kinds of problems.

Start by checking and cleaning off the battery terminals which can also end up with acid deposits on them which also hinders conductivity.

I like to use a fine wire brush and a cloth to remove light corrosion, and a fine coating of WD-40 can ward off future rust and corrosion to boot.

Don’t forget to check the connections at the other end including the earth, these are usually more susceptible to traditional rust and can require a good clean up from time to time.

how to start a car with a bad starter with a screwdriver

Older cars can often suffer from faulty ignition switches or starter relays which can be a very involved process to replace.

In this scenario, you can learn a thing or two from car thieves of the past and crack out your trusty screwdriver and start the car without either.

As the starter motor is directly connected to the battery’s positive terminal, you can simply use a large screwdriver to bridge both the positive connection on the starter motor and the solenoid’s connection at the same time.

When you do this, it will completely bypass the starter relay and the ignition switch and the starter should burst into life and start the engine.

Classic BMW ignition switch and instruments.

Tapping the starter with a hammer

A tired old starter motor will likely develop the odd dead-spot or two between its armature and field coils. The field coils rotate at speed enclosed in the armature, and if there is a dead spot or two, and the starter happens to stop in that position, then it won’t be able to start turning again without some external assistance.

Lightly tapping the starter with a hammer while turning the key in the ignition simply gives it a helping hand and hopefully can get it to turn just enough to get out of the dead spot and spin.

You don’t even need to use a hammer, you can use anything which will give a solid tap, such as a big spanner. That’s handy to know if your starter motor is positioned in an awkward place.

How to Push Start a Car

Push starting a car (also sometimes referred to as bump starting) is an old favourite trick of mine. It’s a method that’s got me out of trouble more than once in the past when my car had a weak battery.

Sadly, this method will only work with a manual transmission car. If your car is an automatic you won’t be able to put the car in gear manually to do it.

If you trying to find out how to start a car with a bad starter automatic transmission, then you’ll want to skip this one or focus on the methods described above.

The technique for push starting a car is as follows:

  1. Turn the ignition to the on position with the key
  2. Depress the clutch and shift into first gear
  3. With the clutch depressed, get a friend to give the car a push
  4. When the car reaches around 5mph, lift your foot off the clutch swiftly and the engine should burst into life

However, after you’ve push started your car and driven off towards your destination, it’s easy to forget that you’ll have to do the same again when you switch it off.

More experienced push starters will be careful to park their car with a weak starter on a hill, with space to manoeuvre the car onto the road without the need for a three-point turn.

Bear in mind that this will work just as well in reverse, but either way, your car will not have power steering or power brakes while the engine is off so its worth being very careful not to lose control.

If your car is parked on a hill, you can often push start it solo by releasing the handbrake and allowing gravity to do the pushing.

Can you jump start a car with a bad starter?

Jump starting a car refers to the technique of hooking up the battery from a healthy car via jumper cables to give your own battery a boost in order to get the car started.

Simply connect the positive and negative terminals of both batteries together after arranging the assisting car into a convenient position for them to reach.

How to jump start a car with battery cables.

This is an old-school technique which can get you out of a sticky situation if the reason your car won’t start is that the battery is weak.

Unfortunately, if your car simply has a bad starter then additional electrical amps are unlikely to make a difference. If it’s a combination of factors, then it may well be worth a try.

It can also aid in diagnosing whether your car has a bad starter or whether it’s just that the battery is past its best.

Hopefully, the above tips and tricks on how to start a car with a bad starter will prove useful when the unexpected happens. With old cars, you will learn to always expect the unexpected.

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