The situation when a car suddenly refuses to start from the starter is familiar to many drivers, especially in the cold season or after a long period of inactivity. A discharged battery, oxidized terminals or a malfunctioning relay can turn a trip into a serious problem that requires an immediate solution. At such moments, an old method proven over decades comes to the rescue - starting the engine from the pusher, which allows you to start the engine without the participation of the standard starting system.
However, the effectiveness of this method directly depends on proper preparation and selection of the transmission operating mode. Many beginners mistakenly believe that it is enough to simply engage any gear and push, but this is not always the case. Manual transmission (manual transmission) requires strict adherence to the sequence of actions so as not to damage the engine or transmission components.
In this article, we will analyze in detail which gear is best to start with, how the algorithms differ for injection and carburetor engines, and why modern cars with automatic transmission are almost impossible to start in this way. Understanding the physics of the process will help you avoid costly repairs and successfully start the engine even in the most difficult conditions.
The principle of operation of starting an engine from a pusher
To understand which gear to choose, you need to understand the physics of the process. An internal combustion engine cannot operate on its own; it requires an external impulse to complete the first stroke - the intake and compression of the fuel-air mixture. In normal mode this work is performed starter motor, which spins the crankshaft to a certain speed.
When starting from a pusher, the role of the starter is taken over by the driving wheels of the car. When you push your car, the kinetic energy of the movement is transferred through the wheels to the transmission, then to the transmission input shaft, and finally to the engine crankshaft. If the crankshaft rotation speed reaches the required minimum, the ignition and fuel injection system will begin to operate and the engine will start.
Why is it more difficult to start a diesel engine?
Diesel engines have a higher compression ratio than gasoline engines. This means that significantly more cranking force is required to ignite the fuel. Therefore, it is more difficult to start a diesel engine from a pusher, and it requires a higher acceleration speed or the assistance of a more powerful towing vehicle.
The key here is the gear ratio of the selected gear. The higher it is (as in first gear), the more effort you need to make to turn the engine, but the higher the risk of jerking. The lower the gear ratio (as in third or fourth), the easier the shaft turns, but more vehicle speed is required to achieve the desired speed.
Gear selection: first, second or third?
The most common question among car enthusiasts is which gear is optimal for starting. The answer to this is not clear and depends on the type of engine, the condition of the car and environmental conditions. Let's look at the characteristics of each mode.
First gear has the highest gear ratio. This means that it transmits the maximum torque to the wheels, but also requires the greatest effort to rotate the engine. When trying to start the engine in first gear, the car often jerks forward, which can lead to hitting people pushing or colliding with an obstacle if the driver does not have time to depress the clutch.
Second gear is considered the “golden mean” for most passenger cars with an engine capacity of up to 1.6–1.8 liters. It provides a balance between cranking force and smooth operation. The risk of a jerk is much lower here, and the probability of a successful start is high, since the engine speed is gained quite quickly.
Third and fourth gears used less frequently, mainly for large-volume engines or in winter, when the engine oil is thick and creates high resistance. In these gears, the shafts spin the easiest, but to start you need to accelerate the car to a speed of 20–25 km/h, which is not always possible in urban conditions.
The best choice for a standard gasoline car is second gear. For diesel engines or cold starts in winter, it is better to try the third one.
Startup algorithm for manual transmission
The process of starting the engine from a pusher requires precise coordination of the actions of the driver and assistants. An incorrect sequence can lead to the car simply not starting, or, worse, an accident. Below are step-by-step instructions.
First you need to make sure that the car is safe and does not interfere with other road users. Turn the ignition on to activate the fuel pump and engine management system. If you have a carbureted car, it may take several presses on the gas pedal to pump fuel.
Depress the clutch pedal all the way and engage the desired gear (usually second). After this, start accelerating the car with help or towing. When the speed reaches 10–15 km/h, you need to smoothly but quickly release the clutch pedal. At this point you will feel the engine “catch” and start working.
- 🚗 Help: for a light car, 2-3 people are enough; for a heavy SUV, 4-5 people or towing may be required.
- 🔑 Ignition: do not forget to turn the key to the “On” position, otherwise there will be no spark, and gasoline will simply flood the spark plugs.
- 🛑 Braking: As soon as the engine starts, immediately depress the clutch and press the brake so that the car does not start moving on its own.
☑️ Checklist before launching from a pusher
This is necessary in order to generator managed to charge the battery, otherwise the next time you try to start the situation will repeat.
Features of starting injection and carburetor engines
The difference in launch algorithms is due to the fuel supply system. Carburetor engines found on older models VAZ, Moskvich and foreign cars before the 90s, are less demanding on the accuracy of the process. For them, only the fact of rotation of the crankshaft and the presence of a spark are important.
In injection engines, the entire process is controlled electronic control unit (ECU). When starting from a push start, it is critical that the ignition is turned on early, as the pump needs time to build up pressure in the fuel rail. If you start cranking the engine before turning on the ignition, the ECU may not respond correctly.
⚠️ Attention: When starting an injection engine, do not under any circumstances try to “gas” the accelerator pedal while rotating the starter or pushing. The ECU itself regulates the air supply, and unnecessary actions can disrupt the startup algorithm or lead to an over-rich mixture.
It is also worth considering the temperature regime. A cold injection engine may require longer cranking or higher pushing speeds for the control system to recognize the "cold start" condition and richen the mixture.
Is it possible to push start an automatic transmission?
Owners of cars with automatic transmissions are often interested in whether the push method works for them. Short answer: practically none. Unlike mechanics, where the connection between the wheels and the engine is rigid (it breaks when the clutch is depressed), in a classic torque converter automatic the connection is made through liquid (oil).
To transfer torque from the wheels to the engine, the automatic transmission requires oil pressure, which is created by the pump. The pump only works when the engine is already running. It turns out to be a vicious circle: to start the engine, you need pressure, and there is pressure only when the engine is running.
| Gearbox type | Possibility to launch | Risk of damage | Required speed |
|---|---|---|---|
| Mechanics (manual transmission) | High | Minimum | 10-15 km/h |
| Automatic (Classic) | Impossible | High (clutch burnout) | - |
| Robot (AMT) | Possible (as with manual transmission) | Medium | 10-15 km/h |
| CVT (CVT) | Not recommended | Critical | - |
Trying to push start a classic automatic transmission can lead to overheating of the transmission fluid and failure of the friction discs. The only exception is some rare cases on older 3-speed automatics, but you shouldn't rely on that. Robotic boxes (Robotic) with one clutch, are essentially electronically controlled mechanics, so you can start them by switching to manual mode.
Risks and precautions when towing
Starting the engine under external influence is stressful for all components of the car. Shifting gears abruptly can lead to breakage of gearbox teeth or even breakage of the timing belt if the engine is seized or frozen. Therefore, it is worth conducting a quick diagnosis before the procedure.
Be sure to check the oil level. If the engine is running dry due to low levels, pushing may be the last thing it experiences. Also make sure that the brake system is working properly, since when the engine is running, the vacuum brake booster will begin to work, and the pedal may become hard or, conversely, too soft, depending on the condition of the system.
⚠️ Attention: It is strictly forbidden to push start a car if there is a suspicion that the engine is seized or the timing belt is broken. Rotation of the shafts in this state will lead to complete destruction of the motor.
When using a towing rope, maintain a distance of at least 4-5 meters. A sharp jerk when engaging a gear can jerk the tow vehicle back or push you off the path. It is ideal if the towing car also has an experienced driver who can synchronize the acceleration.
What to do after a successful launch
Once the engine has “caught up” and started running smoothly, do not turn it off immediately. Your task is to charge the battery. Let the engine idle for a few minutes, then you can start driving. Driving in low gears at high engine speeds will provide a more intense charge than standing still.
If the starting problem persists, you need to check the condition of the battery terminals, the integrity of the wiring and the operation of the generator. It is possible that the battery has expired and requires replacement, even if it looks good on the outside.
If, after a push start, the car stalls when you release the gas pedal, the idle air control valve or throttle valve may be dirty. Try lightly pressing the gas pedal in the first minutes of operation.
In winter, after such a start, it is recommended to check the spark plugs. Frequent push start attempts may cause them to fail. flooding fuel, which in the future will complicate engine operation and increase fuel consumption.
Frequently asked questions (FAQ)
Is it possible to push start a car with a completely dead battery?
Yes, it is possible, but only if the battery is not completely “dead” and is able to at least hold some voltage to operate the electronic ignition and pump. If the automatic transmission is completely discharged to zero, the electronics may not turn on and the car will not start. In this case, you must first “light” or recharge the battery.
Is it harmful to start a car frequently?
It is not very harmful for the engine if it is in good condition. The main impact is taken by the clutch (the discs wear out during a sharp throw) and the gearbox (the gear teeth experience shock load). There is also a risk of damage to the catalytic converter due to unburnt fuel entering in unsuccessful attempts.
Why doesn't the car start from the pushrod in second gear?
There may be several reasons: the acceleration speed is too low, a malfunction of the ignition system (plugs, coils), problems with the fuel supply (pump, filter) or low compression in the cylinders. It is also possible that the gear selected is incorrect for the current oil temperature.
What speed is needed for a push launch?
The optimal speed for starting most passenger cars is 10–15 km/h. Diesel engines or larger vehicles may require acceleration up to 20-25 km/h. Exceeding this speed is pointless and can be dangerous.