The situation when a car is treacherously silent at the most inopportune moment is familiar to many drivers. A dead battery, faulty starter or contact problems can turn driving into a headache. In such cases, a method proven over decades comes to the rescue - starting the engine from external kinetic energy.
However, this process requires a clear understanding of the physics of work transmissions and internal combustion engine. Incorrect actions can cause serious damage to units, especially when it comes to modern cars with complex electronics or automatic transmissions. Before pushing, it is necessary to assess the risks.
In this article we will look at the technical nuances that allow the crankshaft to start rotating without the help of a starter. You'll learn why acceleration speed is critical and which gears to use to minimize load. We will also discuss in which cases it is better to immediately call a tow truck.
How the launch method works
The essence of the “pushrod” method is to force the engine crankshaft to rotate through the transmission. When the car moves, the wheels transmit torque through the gearbox to the flywheel, simulating the operation of a starter. If a spark and fuel are applied at this moment, the mixture ignites.
The key element here is inertia car. The greater the mass of the car and the higher the speed of its movement at the moment the gear is engaged, the more effective the jerk will be. However, excessive speed can result in shock loads that can damage gear teeth or even the timing belt.
It is important to understand that this method only works on cars with manual transmission. In automatic transmissions, there is no rigid connection between the wheels and the engine when the engine is turned off, since the torque converter cannot transmit rotation in the opposite direction without a working oil pump.
An attempt to start an automatic transmission using a pushrod can lead to fatal damage to the automatic transmission due to a lack of oil pressure in the lubrication system.
To start successfully, the engine must reach a certain speed. Typically this value is between 60 and 100 rpm, which is well below idle speed, but is sufficient for the compression stroke and subsequent ignition.
Preparing the vehicle and assessing the situation
Before proceeding to active actions, it is necessary to conduct a quick diagnosis. Make sure that the reason for the lack of starting lies precisely in the starter or a discharged battery, and not in a broken timing belt or lack of fuel. If you hear a characteristic crack or click when you turn the key, but the engine does not engage, the method may work.
Visually inspect the area around the car. You will need a smooth, paved road. Gravel, snow or steep inclines will significantly reduce acceleration performance and increase the risk of loss of control. Also check whether the wheels are blocked by the anti-theft system.
⚠️ Attention: If you suspect a broken timing belt, starting from a pusher is strictly prohibited. Rotating the shafts can cause the valves to meet the pistons and cause major engine overhauls.
Remember to turn on your hazard lights and, if possible, post a warning triangle if you are on a busy highway. The safety of the people involved in the process is more important than the speed of launch. Make sure your assistants understand your commands.
Check the engine oil level. If the problem is caused by jamming due to oil starvation, revving the engine will not help, but will only make the situation worse. A short start is still better than no rotation at all, but it’s not worth the risk.
Starting with assistants: step-by-step instructions
The most common option is to use the physical strength of 2-3 people. The driver sits behind the wheel, depresses the clutch and engages second gear. Helpers begin to push the car, accelerating it to walking speed, approximately 5-10 km/h.
As soon as sufficient inertia is gained, the driver smoothly but quickly releases the clutch pedal. At this moment, a jerk occurs and the engine should begin to turn over. At the same time, it is necessary to add gas to maintain the speed after the flash.
- 🚗 The driver squeezes the clutch and engages 2nd or 3rd gear.
- 🏃 Helpers accelerate the car to a speed of 5-10 km/h.
- ⚡ The driver abruptly releases the clutch and adds gas.
- 🔋 After starting, he immediately squeezes the clutch so that the engine does not stall.
After successful starting, do not turn off the engine immediately. Let it idle until the battery begins to charge. If you release the clutch too early, the car will not move. If it's too late, you'll lose your momentum.
☑️ Checklist before pushing
Sometimes it takes several tries. Pause between jerks so that the participants in the process can take a breath and take the correct positions. Do not try to push a car alone on a steep hill - it is life-threatening.
Launching Alone: Rolling Method
If there are no helpers nearby, the only option is to use the terrain. You will need a slope that the car can accelerate down under the influence of gravity. It is almost impossible to start a car alone on a horizontal surface without a special cable.
The algorithm of actions is similar to the previous one, but gravity works instead of pushers. Get into the car, put it in neutral and let the car pick up speed. As soon as the speed reaches 10-15 km/h, depress the clutch, engage a gear and quickly release the pedal.
Steering becomes difficult and braking distance increases. Be prepared to apply significant force to the steering wheel and brake pedal.
What to do if the slope is not steep enough?
If the car does not accelerate on its own, you can try to rock it by pushing your feet off the ground while sitting in the driver's seat, or use a long strong cable tied to a stationary object (tree, pole) and wrap it around the wheel, but this requires extreme caution.
After starting the engine, immediately put the car in neutral and put the handbrake on, as it may continue to move due to inertia. Make sure you are in a safe place before leaving the salon.
Table of optimal speeds and gears
Choosing the right gear directly affects the success of the operation. First gear creates too much resistance and can cause the wheels to lock or jerk, which can damage the transmission. Third and fourth gears require higher acceleration speeds.
Below is a table to help determine the optimal starting parameters depending on the selected gear and engine size. Data are averages and may vary depending on the condition of the vehicle.
| Transfer | Min. speed (km/h) | Engine type | Risk to transmission |
|---|---|---|---|
| Second (II) | 5 - 10 | Gasoline / Diesel | Low |
| Third (III) | 10 - 15 | Gasoline (small volume) | Medium |
| Fourth (IV) | 20 - 25 | Diesel (high volume) | High |
| First (I) | 3 - 5 | Not recommended | Critical |
Using second gear is considered the “golden mean”. It provides enough torque to turn the engine, but does not cause the wheels to suddenly stop. Diesel engines with high compression ratios sometimes require a higher speed or third gear.
Don't try to use fifth or sixth gear. The gear ratio in this case is too high, and it will be extremely difficult to turn the crankshaft even at high speed. You will only lose precious inertia.
Common mistakes and precautions
One of the most common mistakes is trying to start a car with a completely faulty starter when the engine itself is jammed. In this case, the wheels may become blocked, leading to a skid and an accident. Always check that the crankshaft rotates freely by hand (if possible) or at least listen for sounds when attempting a normal start.
Another mistake is ignoring the state catalytic converter. When starting from a pushrod, the mixture may be over-rich, and unburned fuel burns out in the catalyst, causing it to overheat and melt. Do not repeat the procedure more than 3-4 times in a row.
⚠️ Attention: When starting in a cold gear in winter, there is a high risk of damaging the oil filter or tearing it off the thread due to a sharp jump in oil pressure. Warming up the oil in the pan is critical.
Also, drivers often forget to depress the clutch before engaging a gear during acceleration. This leads to the fact that the car begins to brake with the engine ahead of time, and it is not possible to gain the required speed. Sequence of actions: acceleration -> depress the clutch -> engage gear -> release the clutch.
Don't forget about the safety of passengers. During a dash, they can be thrown forward. Warn them about the moment the engine starts. All people involved in the process should be on the sides of the vehicle, but not in front or behind, to avoid injury.
The success of a push launch depends on the synchronization of the actions of the driver and assistants, as well as the correct choice of gear (optimally 2nd).
Frequently asked questions (FAQ)
Is it possible to start a machine gun from a pushrod?
Strongly not recommended. In classic automatic transmissions (torque converter), the lubrication pump is powered by the engine. When towing or pushing, lubrication of the rubbing pairs does not occur, which leads to rapid failure of the box. On some older models this was possible for short distances, but modern assault rifles will not forgive this.
Is it harmful for the engine to start a car?
If the procedure is performed correctly, the harm is minimal. However, sudden jerks can negatively affect the condition of the timing chain or belt, as well as the engine mounts. For a modern engine with an electronic throttle, this is also stressful for the control system.
What to do if the car does not start after 3-4 attempts?
If after 3-4 attempts the engine does not catch, further actions are pointless and can be dangerous. Most likely, the problem is deeper than just a dead battery (for example, lack of spark, fuel or compression). It is better to use wires for lighting or call a tow truck.
Do I need to depress the gas when starting from a pushrod?
On injection engines there is usually no need to pedal the gas; the electronics itself will determine the start mode. On carbureted vehicles, it may be necessary to briefly press the accelerator pedal to pump fuel before pushing forward.