Car troubles are always inconvenient and it only ever happens when you’re in a hurry. Relax, with a little help you can get rolling within minutes, and here’s how.
Use the bump-start procedure to start a vehicle without the use of a starter motor. This method will only work on vehicles fitted with a manual transmission. To jump-start a vehicle, follow these simple steps:
- Driver sits in vehicle
- Ignition switch turned to “On” position
- Gearbox in 2nd gear with clutch pedal pressed
- Have helpers push vehicle
- At 10 mph approx, drivers releases clutch pedal
- Engine starts
In this guide, you’ll learn how to start your vehicle without a starter motor, why you can’t start an auto transmission by bump starting, and mechanics tips for swapping out your starter motor.
How To Bump Start Your Car
Bump starting is an easy hack to start your car, it’s not difficult to learn or apply. The principle is simple, we need to turn over your engine quickly enough that the engine starts. This clever hack reverses the relationship between the engine and wheels. So instead of the engine’s power turning the wheels, we’ll use the wheel’s power to turn the engine.
This is a great hack to use when your battery is flat or your starter is faulty, however, this is a miracle cure for general nonstarting issues. If your car has some other problem, a bump start won’t help. It should be noted, this hack will only work for manual transmission cars.
1 Driver sits in vehicle
The driver sits in the vehicle, they have an important job to do at the critical moment in the process. It is possible for the driver to be a pusher also, but this risks a runaway car or personal injury and isn’t advised especially as a first-time bump starter.
2 Ignition switch turned to “On” position
The ignition switch needs to be in the “ON” position, that’s position two. Although we’ll be using momentum and man power to turn over the engine, your car still needs some power in the battery in order for this procedure to work. Your car’s engine is as you know ran by a computer, known as a PCM (Power-train Control Module) and it uses battery voltage to operate.
Other critical components require voltage also, your fuel pump is electric the pump sends gas from the tank to the engine without power the engine won’t receive any gas.
3 Gearbox in 2nd gear with clutch pedal pressed
The driver places the gearbox in second gear, presses and holds the clutch pedal down, and awaits their time to shine. Why second and not first gear? Second gear offers greater momentum, first gear tends to concentrate the momentum in a smaller window.
4 Have helpers push vehicle
The more helpers you have the easier this will be. At least two pushers are needed and more if your car is an SUV or truck. Pushing downhill likewise will make the whole job a breeze. If on the other hand, your car happens to be pointed uphill, you can attempt the bump-start procedure in reverse but it is more difficult.
As an alternative to using manpower to push your car, instead tow it with another vehicle. However, if you choose to tow start, make sure the tow rope is sufficiently so you don’t rear-end your tow car.
5 At 10 mph approx, drivers releases clutch pedal
Once the vehicle has gained enough momentum about 10-15 mph, the driver takes their foot off the clutch, known as dropping the clutch. The wheels are now connected to the engine and the engine turns over. However, it’s not enough that your engine turns over, it must turn over quickly. That’s because your engine is fitted with a sensor that detects engine movement.
As the engine cranks over, the crankshaft sensor (also known as CKP or engine speed sensor) produces a voltage. The voltage is the PCM signal to initiate the start procedure, it sends power to the coils for spark and power to the fuel injectors for gas. A slow crank speed means the start signal isn’t sent to the PCM and so these critical components are activated.
6 Engine starts
Modern cars start quickly when bump started. The spark and fueling systems are sophisticated and don’t generally require much effort to start. If you are struggling to start your vehicle, you may have more than a bad starter or soft battery. An engine fault code reader may be needed to read any DTC’s logged.
Is Bump Starting A Car Bad?
Bump starting your car isn’t ideal, calling a tow truck is the correct course of action but not always an option. But you need not concern yourself, bump starting your car once in a while won’t cause any damage. If you were to bump start it all the time, however, you may cause issues with the gearbox, drive axle, and motor mounts.
Common Causes Of No Crank?
I’m a mechanic for over twenty years and here’s a list of the most common causes of a no crank in a manual transmission car.
- Flat battery
- Bad battery connection
- Bad battery
- Faulty starter solenoid
- Faulty starter relay
- Faulty clutch sensor
- Inertia switch fault
In addition to all of these, an auto transmission car may have exhibited a no crank because of a PRNDL fault.
If your car makes a clicking noise when you turn the key, check out this post, it covers all you need to know – “Car won’t start clicking sound”.
I wrote this post about troubleshooting a no-crank – “Jump start a car with bad starter”.
I wrote this post about engine damage and a no crank, lets hope you don’t need this one – “Will a blown engine crank?”
How To Fix The Starter In Your Car?
Starter motors areas you know important bits of kit and just attempting to push your car will give you some idea of how difficult their job really is. But remarkably starters are quite durable and often give great service for years and years without any maintenance.
A starter motor will often give you warning of its demise, slow crank, unusual sounds when cranking, occasionally offering a click sound instead of the usual sounds, the starter may stop mid crank. It is not unusual for the starter to work fine one day and just not work the next.
Stater motors can’t be repaired while in the vehicle, they must be removed. On most vehicles, removal is easy and can be undertaken with just basic tools. Higher-end vehicles however tend to be compact under the hood, and often that means taking off other components to gain access. Exhaust systems, cooler lines, engine mounts, etc.
Once the starter motor is free, you’ll have a choice of having your old unit reconditioned or buying a new starter off the shelf.
Mechanics tips when swapping out starter motor:
- Always buy quality parts, you only want to fit your starter once.
- Use a Keep Alive Memory (KAM) tool before removing the battery cable.
- Check resources like Google or YouTube, for helpful tips about your make and model.
You can check out the KAM tool I use here on the Auto electrical repair tools page.
But before we condemn the starter, it’s better to diagnose the failure, better to check a fact is a fact. Here’s a link you might find helpful, I wrote this post about diagnosing your starter motor and how to fix it – “Jump start a car with bad starter”.
You might also like this post “Is it hard to change a starter motor?”
Can You Push Start A Diesel Car?
It is possible to push start a manual transmission diesel car but not an automatic diesel car. Diesel engines areas you know are generally more difficult to start than gas engines. Diesel requires heat to ignite the diesel fuel and so employ glow plugs to help the start procedure.
That said, modern diesel is very well designed and creates enough heat to ignite the diesel by compression heat alone. Modern engines will only employ glow plugs (aka heat plugs) if ambient temperatures are low.
To push-start your diesel, you’ll need plenty of help. Diesel cars are heavier than gas, mostly because diesel engines are usually fitted to larger cars, SUV’s and trucks. But the diesel engine itself is made from heavier materials. They need to be more robust as they are under much greater stresses than a gas engine.
Follow the bump start procedures as above to start your diesel, however, a tow start will make more sense, pushing a diesel isn’t easy.
How To Push Start A Car Automatic
It is not possible to push-start an automatic car. Unlike a manual transmission vehicle, an auto transmission uses a fluid coupling. That simply means the drive train (engine to wheels) is not physically connected.
Instead, in auto transmissions, an impeller attached to the engine turns the wheels by forcefully throwing fluid at a turbine, which is connected to the wheels through the transmission.
The only way to start an automatic car is with a good battery and starter motor. This guide shows you how to bypass your ignition system and power the starter directly. – “Jump start a car with bad starter”.
Can You Push An Automatic Car If Broken Down?
An automatic car may be pushed but you’ll first need to place the transmission in neutral. This as you know will mean the ignition switch first needs to be turned to the “On” position. You’ll also need to place your foot on the brake pedal to release the shifter’s safety interlock.
In addition, the ignition switch will need to remain on and in the vehicle while the shifter is in the Neutral position. Leaving the shifter in “N” for long periods will drain the vehicle’s battery.
Can you push a car in park? When an automatic car is in Park, the wheels and transmission are locked and can not be pushed. To push a car with an automatic transmission, follow these steps:
- Turn ignition on
- Remove the parking brake
- Place your foot on the brake pedal
- Move the shifter to the “N” (Neutral) position
- Car is now free to move
- About the Author
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John Cunningham is an Automotive Technician and writer on Rustyautos.com. He’s been a mechanic for over twenty-five years and has worked for GM, Volvo, Volkswagen, Land Rover, and Jaguar dealerships.
John uses his know-how and experience to write fluff-free articles that help fellow gearheads with all aspects of vehicle ownership, including maintenance, repair, and troubleshooting.