The car stalls at idle - reasons

Many drivers are familiar with the situation when the engine starts to run erratically or stall at idle. After the driver takes his foot off the gas pedal, the tachometer may show a normal number of revolutions, or vice versa, its readings are constantly changing and dips in the engine are felt, and after a while it completely stalls.

There can be many reasons for such a malfunction, they depend on the type of engine - injector, carburetor - on the make of the car, on the type of gearbox. In addition, such problems are inherent not only in domestic cars, but also in foreign cars with a noble origin. Let's try to figure it out.

The main reasons for the engine to stop idling

Even experienced drivers cannot always correctly diagnose a problem. Several main reasons immediately come to mind:

the idle speed sensor is out of order;
throttle body has not been cleaned for a long time;
failure of the throttle position sensor;
the nozzles of the injection system are clogged;
The carburetor is not working properly, water in the carburetor.

Of course, there are also such banal problems as a broken battery terminal, an empty tank, and poor fuel quality. But this is already a separate case, and it is not worth describing how to get rid of them.

Ways to solve problems

So, idle speed sensor - it is also a valve, it is also a regulator, it is also an electro-pneumatic valve - it is responsible for supplying air to the manifold bypassing the throttle. If it fails, then air can only enter the manifold through the damper, respectively, as soon as you take your foot off the gas pedal, the engine starts to stall.

Also, the reason may lie in the fact that the air channel through which air enters bypassing the throttle is clogged. Be that as it may, but in this case it is worth completely dismantling the sensor, cleaning the channel and installing a new one.

If the problem is in throttlethen you will have to clean it completely. To do this, it is dismantled, disassembled, cleaned with the help of special tools and installed in place.

Throttle position sensor - DPDZ. If failures and engine stops at idle are observed, then the “Check Engine” will inform about the breakdown of the TPS. The sensor is connected to the throttle axis and reacts to its changes, transmitting this information to the CPU. If the information is transmitted incorrectly, then the fuel system will not be able to work correctly. It is not difficult to replace the sensor yourself - it is located on the throttle valve pipe, you just need to unscrew the two bolts, having previously snapped off the block with wires, and screw on the new sensor.

The car stalls at idle - causes

If problems in injectors, then it is necessary to flush the injector with the help of special compounds that are sold at any gas station, they are added to gasoline and they gradually do their job. Although a more effective procedure is to purge the injector, which is performed on special equipment.

If you have carburetor and water accumulates in it, this may be caused by condensation. In this case, you will need to remove the carburetor cover and get rid of moisture. If the problem persists, all water must be removed from the fuel tank and fuel lines.

It is worth noting that diagnosing a particular problem is a difficult task. For example, a breakdown of the idle speed controller can only be guessed by indirect methods, while the “Check Engine” button will inform you about the failure of the TPS.
Additional reasons for stopping at idle

In addition to all of the above, other breakdowns often occur.

Increased gap between electrodes, oiled candles. The solution is to install new spark plugs, install them properly, or clean the old ones.

Air leakage occurs due to the fact that over time, the fastening of the intake manifold cover to the cylinder head weakens from vibrations. Manifold gasket starts to let in air. The solution is to unscrew the manifold, buy a new gasket and use sealant to fix it in place and screw the manifold back in accordance with the prescribed torque - too weak or too strong tightening of the studs leads to damage to the gasket.

Also, air can leak through the carburetor or mixing chamber gasket.

Another important issue is incorrectly set ignition. The spark appears prematurely or late, as a result of which detonations do not occur at the moment when they should be. The solution is to set the exact ignition timing using the ignition coil and the crankshaft pulley, which must be combined with the marks on the timing cover.

The list can go on for a very long time. But the most important thing is to correctly diagnose the cause of the breakdown, even the smallest gaskets, cuffs or seals break over time, and this leads to serious problems.

Video for those whose car stalls at idle. The solution to this problem on the example of a VAZ 2109 car.