Dips when you press the gas. Failure of the gas pedal

2024 Author: Erin Ralphs | [email protected]. Last modified: 2024-02-19 11:42

Failure of the gas pedal - a rather rare phenomenon for modern cars. However, if you notice that your iron friend began to twitch when you press the gas, do not put off solving this problem for later.

In today's article, we will find out the causes of this phenomenon, as well as consider ways to solve this problem.

What is this?

Failure when pressing the gas pedal is a sudden failure in the operation of the internal combustion engine, which can occur in any of the modes and loads. Sometimes it can be accompanied by a sudden braking of the car and its stop. There are several types of this phenomenon:

• Short dips when pressing the gas pedal (about 2-3 seconds).
• Twitching (a series of jerks while moving).
• Deep dip (can last up to 10 seconds).
• Dash (1-2 seconds).
• Wobbling (series of dips).

Possible causes

Most often this problem is associated with a spontaneous change in frequencycrankshaft rotation. The latter can produce revolutions regardless of the position of the accelerator. That is, the problem is accompanied by a delay in the response of the motor to pressing the accelerator.

Jerks and dips when you press the gas can occur during acceleration, at the beginning of the movement, with a constantly stable position of the accelerator. You can determine the true cause of this phenomenon yourself (by checking the condition of the sensors) or using diagnostic equipment. Most often, jerks and dips occur due to abnormal fuel pressure in the rail. Also, the problem may be hidden in a malfunction of the DMRV (mass air flow sensor) or TPS (throttle position device). These two mechanisms are responsible for mixture formation, namely for the supply of a specific portion of air. These sensors rarely break, but failures when you press the gas most often occur through their fault. Sometimes they just have clogged contacts.

Dips in motion

Jerking of the car at the moment when it starts moving, occurs, as we have already said, due to the delay in the response of the motor to pressing the pedal. The jerk itself occurs when the throttle is open, that is, when, according to the TPS signal, the electronic control unit determines the moment of transition from idle to load mode. At this time, the fuel supply should be as high as possible. If the system does not provide a normal level of pressure, the machine is not able to continue moving - it stops and stalls. For the ECU, the location of the pedals inthe car is not important, since all actions with the supply and analysis of electronic signals are carried out automatically.

For the same reason (low fuel pressure), the car cannot accelerate. Here, the control unit, as in the previous case, seeks to increase the fuel supply by giving a signal to open the throttle. But due to low pressure, dips are noticeable, and, accordingly, a decrease in speed when moving.

Dips in speed: what to do?

If the car has already picked up speed and is moving at a stable speed, but suddenly there was a failure, then it was caused by a malfunction in the ignition system. In this case, it is necessary to diagnose it. It is done as follows.

First you need to turn off the ignition, then pay attention to the reliability of fastening the wiring harness block to the ignition coil. When starting, the motor should not emit a characteristic crack (if this is observed, it means that a breakdown of high voltage has occurred).

Often, failures when you press the gas happen due to a poor-quality spark plug. Using a candle key, we unscrew each of them and evaluate the external condition. At the end there should be no soot and oxidation. The very ability of the element to form a spark is determined by the ignition tester (for example, the domestic Test-M device). If, after installing new candles, the car twitches again when driving, inspect the throttle position sensor. A malfunction of this mechanism may be reported by signs such as:

• Sudden reduction in engine power.
• Irregular idling.
• Changes in fuel consumption.

Engine Trouble

This phenomenon can also cause a failure when the gas is pressed sharply. The fact is that during tripling in an engine out of 4, 1 or 2 cylinders do not work at once. Hence all the ensuing consequences.

Below we list the main signs indicating this phenomenon:

• Weak acceleration dynamics (even at high speeds).
• Change the sound of the exhaust.
• Uneven engine idling, slight engine shaking.
• High fuel consumption. It can increase by 20 or even 50%.
• Darkening of one or more spark plugs.
• Constant jerks while driving and accelerating.

As you can see, the device of a car is such that the motor itself will make itself felt in case of any breakdown. Most often this happens due to incorrect ignition timing. Also, tripping occurs with faulty candles. The latter does not emit sparks to ignite the mixture, resulting in poor acceleration dynamics and increased fuel consumption. Less commonly, this problem is provoked by worn piston rings or piston/valve burnout.

To solve this problem, you should determine which of the cylinders stopped working. To do this, alternately removedhigh-voltage ignition wire from candles. But this is done with special care, since there is a risk of electric shock to the body. After removing one of the wires, the engine speed rises to 1.5 thousand. The valve is also removed from the cylinders one by one. If the sound of the engine has not changed, then the cylinder is working correctly, and the search for a non-working element continues. And so on until the faulty mechanism is found.

High voltage wire diagnostics

Since this part is an integral part of the ignition system, it should also be diagnosed. To do this, we need to remove the tip that is put on the candle. The wire itself is in a special winding. Its tip has a special persistent penny. Through the last part, current is supplied to the candle. So, the core of this wire should fit as tightly as possible to the penny. Over time, this place can oxidize, due to which the current supply stops or occurs partially, which provokes the engine to triple.

How to check contact oxidation? This is done in the following way. The second probe of the multimeter is connected to the central core of the wire. If the values on this device have not changed, then this place has poor contact. In this case, the damaged area is cut off by 0.5-1 centimeter. Sometimes the core of the wire can be deformed or oxidized not at the tip, but near it. In this case, you need to cut the cord until the multimeter shows voltage (of course, if the length of the mechanism isallows).

Corrector gas pedal

Some motorists, in order to reduce dips when you press the gas, install the so-called correctors. They can be purchased at a price of 3 to 10 thousand rubles. Such devices electronically shorten the accelerator stroke. The location of the pedals in the car does not change. Usually correctors have a removable remote control and operate in three modes ("Sport", "Speaker" and "Economy").

In principle, this device does not solve the problem with jerks, therefore only avid tuning enthusiasts install it. By the way, after such an upgrade, many drivers complain about difficult traffic jams - the car starts to twitch even more.

Conclusion

So, we examined the features of failures when pressing the gas pedal and found out how to fix this malfunction with our own hands. As you can see, to cope with this problem, it is not at all necessary to go to a car repair shop. It is enough to at least superficially know the device of a car.