Letters with a problem began to arrive in my mail high speed when starting the engine. Immediately, the arrow rises by about 3,000 and after a few seconds falls to its normal position. We will argue logically. Why do we have engine speed? Revolutions directly depend on the opening angle throttle... The greater the angle it is open, the higher the engine speed. Whoever has a BC, the easier it is, they can just look at the readings of the IAC and determine whether this is the case. Those who do not have a bookmaker will need the help of a friend. You need to put him on the driver's seat, and open the hood yourself and observe the metal lever connected to the throttle axis (located in the center of the plastic washer on which the throttle cable is attached). You can watch the video on the page:. This lever is fully associated with the IAC - idle speed regulator. Ask a friend to turn on the ignition. The lever should tilt to the left, opening the throttle to start. The amount of deviation will depend on the engine temperature. If, after starting, the lever deviates even more to the left, thereby opening the damper more, just by 3,000 rpm, and when the speed drops, the lever together with the damper will close - then it’s the IAC. Turnovers correspond to the position of the remote control.

Let's look at another option. Let's say our IAC is working properly. What causes the revs to rise? I often go to forums to see what new sores are popping up on our cars. And there is a wrong opinion. The question is: "Why small turnovers?" And in the answers they write that you need to look at all the hoses, if there are any cracks and if there is air leakage. They write correctly, but only for cars with a mass air flow sensor - a mass air flow sensor. This sensor is installed after air filter and takes into account the air flow passing through it. And the air leak comes after him, and he is not able to determine it. It turns out that the engine passes more air, and the mixture becomes lean, which leads to a decrease in rpm.
... ... We have the opposite. There is a DBP, and it determines the absolute pressure in the intake manifold. If there is air leaks, then he will catch it. It turns out that the damper passes its portion of air, and the suction adds its own. DBP takes into account everything, and the revolutions increase. And in any case, the injectors inject as much gasoline as is needed for the engine to function properly. This is a plus for us. Soon, the ECU will understand that the speed is too high and will give a command to the IAC to cover the DZ - the throttle valve, and everything will be settled. The next time you start, everything should be repeated. Now let's think about where the excess air can come from, other than bursting hoses. Three systems come to mind, although even 4.

If the piston is jammed or the spring burst in the pcv valve - crankcase gas removal, then the air will simply be sucked, bypassing the damper, through a long hose, through valve coverthrough the faulty valve into the air manifold.
... ... If the valve is faulty USR system exhaust gas recirculation, the gases will also go to the air manifold through a metal tube. It is better to turn off the EGR valve immediately:.
... ... If the adsorber purge valve is faulty, then gasoline vapors will also go through the pipe to the manifold.
... ... And the last system that connects to the air manifold is a system for changing its length. To the right of the collector is the actuator itself, black plastic, looks like a mushroom cap. It has a fitting on top, and a black tube is connected to it through a rubber tip. The other tube of this system is connected to the air manifold itself. In this mechanism itself there is a membrane - a diaphragm, and if it is torn, then air will flow through these tubes into the manifold until the engine exceeds 4000 rpm. And then just switch to the short collector and close this circle. Tomorrow we have Monday, I will go to work. I think there will be free time for the experiment. I have a lot of plugs on the intake manifold fittings, and even different diameters. We will simulate air leaks and see how the engine will behave. Then we will definitely find out whether our theoretical conclusions and logical chain are correct. OK, see you tomorrow. I think by the evening by 10 o'clock I will post the video both on the blog and on YouTube.
... ... Well, everything is ready.

All car enthusiasts sometimes face such a problem as increased idle speed. But, unfortunately, it takes a newbie a lot of time to find and fix this problem without a visit to a specialized car service. To do this, you will need a detailed manual, which will specifically describe all the necessary steps.

When starting, the engine may gain over high revs for faster warm-up. This is especially often manifested in winter period... But after a while, after reaching the minimum working temperature the electronic control unit is triggered, which reduces the engine speed to a normal value. If this does not happen, then it is necessary to urgently search for the causes of this problem.

Increased speed indicate more intensive engine operation, which can lead to a wide variety of consequences. Prolonged operation can cause the engine temperature to rise significantly, leading to thermal shock. This will cause the cylinder block to work. In addition, most of the nodes will receive a strong output due to unstable engine operation and, as a result, accelerated wear. All this will affect the engine life.

Therefore, it is necessary to immediately figure out what reason caused the increase in speed. There are several of them:

• idle speed sensor
• throttle angle adjustment problems
• failure of the engine temperature sensor
• air ingress through a damaged intake manifold
• problems with electronic unit management

Ways to solve problems

Diagnosing this problem requires some knowledge, as the process can cause irreparable damage to the engine. Therefore, you must carefully read the instructions for use. this car... It is also important to remember that Chevrolet Niva cars are installed gasoline engines injection type, therefore, the increased idle speed on a warm engine is most likely caused by the electronic components of the car.

Idling sensor check

To do this, the engine is warmed up to operating temperature. Then only the sensor is checked with a multimeter. In case of malfunction, you must replace it with a new one.

Throttle position sensor

This component is responsible for the amount of air mixture entering the engine's combustion chamber. If the sensor is not correctly adjusted, then the oversaturated fuel will detonate more, spinning the engine faster and increasing the revs. The sensor is also checked using a multimeter.

Throttle travel problems.

These problems are similar to the failure of the throttle sensor and lead to the same consequences. Only the main problem here is not an electronic one - but the contamination of the damper itself by oil vapors coming from the crankcase, residues of combustion products or due to a rare change of the air filter. If there are traces of dirt, the damper must be cleaned. To do this, remove the throttle assembly completely and either replace it if damaged or clean it using special means... It is important to remember that after cleaning the throttle angle may be incorrectly set, due to the so-called "memory effect" in the ECU. In this case, on some models, additional computer diagnostics will be required.

Engine temperature sensor.

This component most often fails because it is constantly exposed to strong high temperatures. Therefore, in some cases, it is better to start looking for problems with it. It is checked in the same way, using a multimeter. After replacement, cleaning of the ECU errors may be required.

Damage to the intake manifold.

The collector itself may fail if the car has a sufficiently large resource. But more often the gasket fails. In this case, excess air is sucked in. To eliminate the problem, it is necessary to dismantle this part, as well as the nodes on which the injection elements are located. Before installing the gasket, carefully grind the surface of the collector and clean it from traces of the old gasket. But it is important to remember that the occurrence of this problem is accompanied not only by increased idle speed. Damage to the gasket leads to the fact that it is more difficult to start the engine, the speed floats while driving.

As you can see from practice, there is a very a large number of problems that can cause increased idle speed on a warm engine. Therefore, if in doubt that dIY repair will not bring the desired result, it is better to entrust the car to specialists who, with the help of professional equipment, will be able to quickly identify the defect and eliminate it.

Why on the Chevrolet Niva there are increased idle speed on a warm engine All motorists sometimes face such a problem as increased idle speed. But, unfortunately, it takes a newbie a lot of time to find and fix this problem without a visit to a specialized car service. To do this, you will need a detailed manual, which will specifically describe all the necessary steps.

Table of Contents 1 Main Causes 2 Solutions 3 Idle Speed \u200b\u200bSensor Test 4 Throttle Position Sensor 5 Throttle Travel Problems. 6 Engine temperature sensor. 7 Damage to the intake manifold. Root Causes When starting, the engine may speed up higher to warm up faster. This is especially true in winter. But after a while, after reaching the minimum operating temperature, the electronic control unit is triggered, which reduces the engine speed to a normal value. If this does not happen, then it is necessary to urgently search for the causes of this problem. Higher revs indicate more intensive engine operation, which can lead to a wide variety of consequences. Prolonged operation can cause the engine temperature to rise significantly, leading to thermal shock. This will cause the cylinder block to work. In addition, most of the nodes will receive a strong output due to unstable engine operation and, as a result, accelerated wear. All this will affect the engine life. Therefore, it is necessary to immediately figure out what reason caused the increase in speed. There are several of them: idle speed sensor throttle valve sensor problems with adjusting the angle in the throttle valve failure of the engine temperature sensor air ingress through a damaged intake manifold problems with the electronic control unit

Ways to Solve the Problem Diagnosing this problem requires some knowledge as the process can cause irreparable damage to the engine. Therefore, you must carefully read the instructions for using this car. It is also important to remember that petrol injection-type engines are installed on a Chevrolet Niva car, therefore, the increased idle speed on a warm engine is most likely caused by the electronic components of the car. Checking the idle speed sensor To do this, the engine is warmed up to operating temperature. Then only the sensor is checked with a multimeter. In case of malfunction, you must replace it with a new one. Throttle Position Sensor This component is responsible for the amount of air that enters the engine's combustion chamber. If the sensor is not correctly adjusted, then the oversaturated fuel will detonate more, spinning the engine faster and increasing the revs. The sensor is also checked using a multimeter.

Throttle travel problems. These problems are similar to the failure of the throttle sensor and lead to the same consequences. Only the main problem here is not an electronic one - but the contamination of the damper itself by oil vapors coming from the crankcase, residues of combustion products or due to a rare change of the air filter. If there are traces of dirt, the damper must be cleaned. To do this, you must completely remove the throttle assembly and either replace it if damaged or clean it using special tools. It is important to remember that after cleaning the throttle angle may be incorrectly set, due to the so-called "memory effect" in the ECU. In this case, on some models, additional computer diagnostics will be required. Engine temperature sensor. This component most often fails because it is constantly exposed to strong high temperatures. Therefore, in some cases, it is better to start looking for problems with it. It is checked in the same way, using a multimeter. After replacement, cleaning of the ECU errors may be required.

Damage to the intake manifold. The collector itself may fail if the car has a sufficiently large resource. But more often the gasket fails. In this case, excess air is sucked in. To eliminate the problem, it is necessary to dismantle this part, as well as the nodes on which the injection elements are located. Before installing the gasket, carefully grind the surface of the collector and clean it from traces of the old gasket. But it is important to remember that the occurrence of this problem is accompanied not only by increased idle speed. Damage to the gasket leads to the fact that it is more difficult to start the engine, the speed floats while driving.

As with many other malfunctions, the causes of high idle engine speeds should be looked for from simple to complex. In fact, there can be many reasons for these, but among them the most common ones can be distinguished:

• big idle speed due to air leaks from the manifold (followed by hitting the engine);
• increased idle speed due to leak in the vacuum line;
• high idle speed due to faulty ignition system engine.

As you can see, these reasons are quite "smeared", and they should be specified. But the first thing to do is the standard procedure - turn off the car, remove the negative terminal of the battery for 15-20 seconds, then plug it back in and check if the problem remains.

High idle engine speed due to air leaks and vacuum line leakage

So, if the cause of high idle speed was excessive air ingress into the engine, then the first thing to check is the throttle cable. Because of it, the damper can remain unnecessarily open at idle, as a result of which the latter grow. This happens because the "brains" of the engine see that a lot of air (more precisely, oxygen) is entering the manifold, and therefore they adjust the fuel supply by increasing it. As a result, the engine speed increases at idle speed. Cleaning the throttle valve with special chemicals can help in this case.

More air can enter the collector due to a leak in the air intake system. In this case, check all vacuum lines, head breathers and all sections of the air line to the engine for air suction. Listen for hissing noises, which can be a key indicator of vacuum leaks and air leaks.

Increased idle speed due to problems in the ignition system

In this case, the reason lies in one of the parts of the ignition system - also a fairly common cause of the problem with speed. Here you should check and, if necessary, replace the distributor cover, ignition wires or simply spark plugs.

Other causes of increased idle speed and solutions:

• Idle sensor... In principle, this malfunction should be included in the list of common ...
• Fuel pressure control can operate at too low pressure. Check the fuel pressure with a dedicated fuel pressure gauge. Replace the fuel pressure regulator if necessary (not independent work for many drivers).
• Incorrectly installed or knocked down ignition timing (in this case, idle speed usually does not increase much).
• The reason may be malfunction in the computerized control system engine. The errors should be read with a scan tool to identify the problem.
• Generator also sometimes causes high idle speeds. If it is not working properly and does not generate enough current, the motor will try to crank it even more to balance the voltage.
• If you know what it looks like and where it is PCV valve and its hosethen inspect them. Use pliers to pinch the hose of this valve. The engine speed should drop slightly. If this does not happen, then it is the faulty valve that is the cause of the increased engine speed - you need to replace it.
• Overheating of the engine or a faulty temperature sensor in rare cases can also cause high idle speed.

description

The procedure is an idle air ECM learning operation to keep the engine speed within the normal range. It must be performed in the following cases:

When replacing the throttle actuator or ECM;

When the speed h.x. or the ignition timing is abnormal.

1.preparation

Before performing the training procedure for air supply at rpm h.x. make sure the following conditions are met. The training procedure is canceled if one of them is not observed even for a moment.

Battery voltage: more than 12.9 V (at rpm);

Engine coolant temperature: 70-100 "С;

PNP switch in "ON" position;

Electrical load switch: in pos. "OFF" (air conditioner, headlights, rear window defogger).

On vehicles equipped with a daytime lighting system, set the light switch to 1 position to turn on only small lights.

Steering wheel: in neutral position (corresponding to straight-line movement);

Vehicle speed: vehicle is stationary;

Transmission: warmed up;

On models with CVT and manual gearbox:

Travel by car within 10 minutes.

2. execution procedure

If there is a malfunction in the accelerator pedal position sensor circuit, it is not possible to switch to diagnostic mode.

1. Perform the accelerator pedal release learning procedure. See above.

2. Perform the Throttle Close Learning procedure. See above.

3. Start the engine and warm it up to normal operating temperature.

4. Turn the ignition key to the "OFF" position and wait at least 10 seconds.

5. Make sure that the accelerator pedal is fully released, turn the ignition switch to the "ON" position and wait 3 seconds.

6. Repeat the following procedure quickly five times within 5 seconds:

Fully depress the accelerator pedal.

Release the accelerator pedal completely.

7. Wait 7 seconds, fully depress the accelerator pedal and hold it for approx. 20 seconds, until the “MI” malfunction indicator stops flashing and turns on with a steady light.

8. Fully release the accelerator pedal within 3 seconds after the malfunction indicator "M |"

9. Start the engine and let it run at idle rpm.

10. Wait 20 seconds.

Go to step 3.

3. check the rpm h.x. and ignition timing

Boost the engine two to three times and make sure the rpm is running. and the ignition timing is normal.

Are the test results normal?

Yes -\u003e End check.

No -\u003e Go to step 4.

4.Identify the faulty component

Check the following:

Check if the throttle valve is fully closed.

Check the operation of the PCV valve.

Check for air leakage behind the throttle valve.

Are the test results normal?

Yes -\u003e Go to step 5.

No -\u003e Repair or replace the defective component.

5.Identify the faulty component

Engine components and their installation condition are in doubt. Check and correct the deficiencies.

If one of the following conditions occurs after starting the engine, eliminate the cause of the problem and re-run the Idle Air Teach from the beginning:

Engine stalls;

Unstable work at speed h.x.

End of check.