One of the problems that a car enthusiast who owns a domestic VAZ 2109 may encounter is that the carburetor stalls while driving. A large number of articles are devoted to this topic, but real experience will allow you to solve the problem faster, since there are several reasons for this.
So, professionals who had experience solving the problem of a VAZ 2109 with a carburetor engine stalling at idle found several reasons and ways to solve them.
Causes and solutions
When the VAZ 2109 carburetor stalls at idle, that is, when your foot is on the gas pedal, the car works flawlessly, and as soon as you lower it, it stalls, you should look for the cause in the idle speed solenoid valve. To find the reason, you need to understand the meaning of the machine. Thus, the carburetor of the car has an idle system, which consists of a fuel channel with a nozzle, an air channel and a solenoid valve. When the car is idling, fuel moves through a special idle passage into the engine. To ensure that the car operates at idle speed, there are holes on the nozzle.
What kind of malfunction causes the idle speed to disappear?
There may be two reasons:
- Problems with fuel supply at idle.
- There is an air leak in the system, which disrupts the optimal proportion of air and gasoline in the combustible mixture.
In the first case, the responsibility falls on the idle air solenoid valve. If it malfunctions, fuel will not be able to flow into the engine.
To eliminate the cause, you should remove the air filter, from which the cover is then removed. After this, a mini service check is carried out. With the ignition on, remove and place the chip on the valve. The serviceability of the coil is indicated by characteristic clicks that are heard during manipulations. But to be completely sure of serviceability, you should unscrew the valve. To do this, use key No. 13. Then remove the jet and check for contamination. Blowing air through your mouth, see if it passes through it normally. After such a check, you need to close the hole in the EAC (hereinafter the idle speed solenoid valve) with your finger and turn on the ignition. This procedure will blow out any debris that has accumulated in front of the fuel jet, if there is any there.
You should also check the integrity of the rubber seal. If there is damage, deformation or a loose fit, air will be sucked in, which is why the machine will malfunction when idling.
If there is no characteristic click when removing and putting on the chip, then you should check whether there is voltage. If it is missing, you should check the carburetor throttle economizer.
If there is voltage, but there is nothing to replace the valve with (the breakdown occurred on the road), then you can take emergency measures that will allow you to complete the route. To do this, you need to remove the nozzle and break off the plastic needle and put the nozzle in place. In this case, there is no need to put a wire on the EPHH.
What to do if there is no idle on a VAZ-2109 car
As mentioned above, this problem is quite common, and this applies to a greater extent to “nines” with a carburetor engine. Here they often get clogged:
Because of this, the speed eventually begins to fluctuate or the engine simply stalls. Fixing this problem is not very difficult. You can do everything yourself, thereby saving a certain amount of money, because you will have to pay for the diagnostics and work of the car service technicians.
In the “nines” the jet is responsible for the stable operation of the carburetor. The problems here arise due to its contamination. Accordingly, to eliminate them you just need to unscrew the nozzle and blow it out with a stream of air. This is the simplest solution to the problem.
However, in case of more serious blockage, it is no longer possible to do without the flushing procedure. This is done using a diluted mixture of acetone or gasoline.
It should be noted that some VAZ “nines” are equipped with jets with a valve that has an electromagnetic control. With its help, the supply of the fuel mixture to the nozzle is adjusted. If the valve is operating normally, the flow stops when the engine speed rises above 2.1 thousand per minute. Manufacturers claim that a breakdown of a jet with such a valve can only be diagnosed at a car service center, using special equipment. However, craftsmen have come up with their own way to avoid a visit to the service station. In particular, you just need to quickly disconnect and reconnect the wire that supplies power to the valve. If, while performing this manipulation, you hear a clear click, it means that everything is fine with this unit, and the source of the problem should be looked for elsewhere.
In the fuel line through which gasoline is supplied to the carburetor, there is a fine filter. Its contamination can also cause problems with the normal operation of the car at idle. According to the recommendations of the manufacturers, this element should be changed after every 15 thousand kilometers. However, the fine filter will only have such a resource if the car is constantly refueled with high-quality fuel. Otherwise, you will have to change it much earlier. It should be immediately noted that the purging procedure is ineffective here. Therefore, change the filter immediately, especially since it is not that expensive.
Incorrect carburetor adjustment is another very common cause of problems with idle speed on the VAZ-2109. In this case, you need to set the screws that regulate the mixture to the correct position. The procedure for adjusting the carburetor is quite simple, and you can do it yourself. The problem may also be caused by air getting into the fuel mixture due to poor sealing of the connections. First of all, you should check the pipe that connects the intake manifold and the brake booster.
On “nines” with an injection engine, the main cause of problems with idle speed is the idle speed regulator. If everything is in order with this unit, you should continue to search for the cause of the malfunction. In particular, you need to check the pressure in the fuel rail. To begin, simply remove the cap from it and press a suitable object onto the valve. After this manipulation, gasoline should spray out in a powerful stream. This means everything is fine. If the gasoline “sputters,” then you should arm yourself with a pressure gauge and measure the pressure. The normal range is 2.8 to 3.5 bar.
Causes of the problem
Quite often, VAZ 2109 owners are faced with a problem when the carburetor does not hold speed while idling, and the engine simply stalls. There can be many reasons, and they are all united by a number of characteristic features.
The first reason is a clogged idle jet. Even though the fuel supply system has 2 filters (coarse and fine), even one speck may be enough to clog the nozzle.
fine filter
Also, the fine filter itself may become clogged. This often happens when the filter was not replaced with a new one in time. Less commonly, malfunctions in the idle system occur.
There is no difference at all between the symptoms for any of the causes of the problem. Determining what exactly needs to be cleaned or changed can only be done through a visual inspection or diagnostics.
Also, sometimes the revs not only disappear completely, but also float. At the same time, the VAZ 2109 car does not stall. In this case, to the above reasons, you should add: a faulty solenoid valve or idle speed sensor.
Determining the quality of the spark
At this stage, you need to understand whether there is voltage on the spark plugs. To do this, just unscrew one spark plug and connect the central electrode to the high-voltage wire. Next, ensure that the threads are in contact with the ground of the car and turn on the ignition. A stable spark of blue (white-blue) color indicates that everything is fine with the ignition.
Check the remaining spark plugs in the same way. Because a common reason for an engine to fail to start is the failure of one of these parts.
After working for a while in this mode, the engine will stall.
Cylinders with non-functioning spark plugs are simply filled with too much gasoline and the situation will repeat itself when the engine is restarted. If there is a spark on all spark plugs, evaluate their color and size. Yellow/red color and small size also indicate that the car will start and subsequently stop working.
At this stage it is enough to replace the failed spark plugs
When purchasing parts, pay attention to the manufacturer’s recommendations regarding clearance and heat rating parameters
Troubleshooting
In order to fix this problem, you need to determine the culprit. Once you have located the location where the problem occurred, you can begin preparing for the repair work. First of all, check whether the carburetor is set correctly. To do this, tighten the quality screw and the quantity screw until it stops, and then unscrew it as indicated in the factory settings of the carburetor (often, the carburetor settings are as follows: quality screw - 2.5 turns, quantity screw - 4 turns). If there are no changes, and the engine still does not idle, or even stalls, then you need to look for the reason, choosing from the above.
The engine stalls periodically
This phenomenon may be due to problems with the ignition system. When driving, chaotic interruptions with sparking on the spark plugs are possible, both on a specific one and on all of them at the same time. The lack of a spark will most likely lead to the unit stopping.
If a car stalls while driving and then starts (including the 2112 VAZ), the most common reasons include the following: malfunction and moisture in the ignition coil, damage to the crankshaft position sensor and ignition module, failure of safety elements of control systems sensors
In this case, you should pay attention to the condition of electrical wires and their connections, which may contribute to power outages
It is very rare for a car to stall while driving and then start again due to a faulty vehicle speed sensor.
Optional equipment
As a rule, the stable engine speed of most cars is affected by turning on the air conditioning compressor. Very often this happens at low and idle speeds. Since the air conditioner consumes a considerable amount of energy, the control unit sends a signal to the power system to increase the volume of fuel mixture supplied to increase idle speed to compensate for the loss of power consumed by the air conditioner.
But when the impulse to turn on the air conditioner does not arrive at the electronic unit due to a communication failure between the computer and the device module, the control unit is not able to assess the situation and add fuel. As a result, the stability of idle speed is disrupted until the moment when the engine completely stalls.
