There probably is not a single owner of a domestic car who would never find himself in a situation in which the engine of his car refused to start. A similar problem is familiar to foreign car drivers, however, our cars suffer from this “disease” much more often.
It often happens that the car starts and immediately stalls . There can be many reasons for this. We will talk about them in this article using the example of a VAZ-2109 car with carburetor and injection engines.
Everything you need to start the engine
To start and stable operation of a gasoline power unit, regardless of the type of power system, you need only two things: a good timely spark in the cylinders and the flow of the fuel mixture into the combustion chambers. In the absence of at least one of these components, all your attempts to start the engine will be futile.
Since it is much simpler to carry out a preliminary check of the ignition system than the power supply system, the diagnosis begins with it.
Check the presence and condition of the spark
Determining whether voltage is supplied to the spark plugs is easy. It is enough to unscrew one of them, connect the central electrode to the corresponding high-voltage wire, ensure the contact of its “skirt” with the “mass” of the car, turn on the ignition and start the starter. If a steady spark of blue or white-blue color is observed on the candle electrodes, everything is in order with ignition. Not superfluous, of course, will be in the same way to check all the candles. The fact is that very often the reason that the car starts and stalls immediately is a malfunction of one or more candles.
First, the engine starts and tries to work on three or two cylinders. This process is accompanied by a characteristic “triple” and increased vibration of the power unit. Having worked a little at idle, the engine will certainly stall. Cylinders with non-working candles are filled with gasoline. When you restart, everything repeats, that is, the motor starts to “grab”, but after a few seconds it stops its work.
If there is a spark on all candles, pay attention to its color and size. If it is yellow or red, and its size is disproportionately small, compared to the interelectrode gap, this may also be the reason that your car starts and immediately stalls .
This problem is solved by replacing non-working candles. When buying them, do not forget to comply with the manufacturer's requirements regarding the incandescent number and clearance.
Diagnose high voltage wires
If you have determined that everything is okay with the spark plugs, and the VAZ- 2109 starts up and stalls immediately, as before, you should check the high-voltage wires. Due to the constant loads created by high voltage, they also often fail. The malfunction of the wires is a violation of the integrity of the conductive core or insulation. In the first case, electricity does not enter the candle at all, as a result of which the spark disappears. If insulation damage occurs, a breakdown occurs between the conductive core and the “mass” of the car, that is, part of the electricity simply goes away. Because of this, the spark loses power, and often the ability to ignite the fuel mixture.
High-voltage wires are checked in the same way as candles. Additionally, the resistance value of the conductive core is measured. Depending on the brand and model of wires, it can be from 0.4 to 0.9 kOhm.
The feasibility of further verification of the ignition system
You checked the candles and high-voltage wires, replaced the faulty elements, but the "nine", as before, starts up and immediately stalls ? There is no point in checking the ignition coil and the switch. Typically, these ignition elements either work or don't work. In other words, if there is a steady spark in all cylinders, the cause must be sought in the fuel system.
Injection Engine Power Sensors
When the engine of your VAZ (injector) starts and immediately stalls , but everything is normal with ignition, first of all pay attention to the instrument panel. All problems of the power unit are recorded by the electronic control unit, about which the driver is notified using the CHECK warning light. In this case, it is advisable to immediately test the device and determine the malfunction by the error code. But if this is not possible, check the mass air flow sensor (DMRV) and the idle speed control (IAC).
Often it is the faulty DMRV that causes the injector "nine" to start and immediately stall . This sensor detects the amount of air flowing through the duct into the intake manifold. Based on its data, the electronic control unit controls the concentration of the fuel mixture. The slightest malfunction of the mass air flow sensor leads to its incorrect formation. As a result, we have an increase in fuel consumption, floating idle, problems with starting the engine.
Well, and how not to mention the idle regulator (sensor). It is he who receives a signal from the electronic control unit about the required amount of air for the combustible mixture and mechanically increases or decreases its volume. The regulator takes a direct part in starting the engine and its operation during the warm-up phase in idle mode. So if your car starts up and stalls right away , be sure to check the IAC as well.
DFID check
To diagnose the mass air flow sensor, we need an autotester or a multimeter. DMRV is located on the duct going from the filter to the intake manifold. To start, start the engine and warm it up to operating temperature. Pay attention to its speed.
Now disconnect the wiring harness block from the sensor. The motor should respond to this by increasing the number of revolutions to about 1,500 rpm. This ECU turned on the emergency operation mode, in which only information received from
the throttle position sensor is taken into account for the formation of the fuel mixture
. If the operating mode of the power unit has not changed, most likely, the DMRV is faulty. To verify this, we use a multimeter turned on as a voltmeter with a measurement limit of 2 V. In the car, turn on the ignition, but we will not start the engine. We connect the red probe of the multimeter in the block to the yellow DMRV wire, black to the green. We look at the readings of the device. A working sensor should have a voltage between its terminals of 0.996-1.03 V. If it exceeds 1.05 V, the device has definitely become unusable.
IAC verification
To check the idle speed controller, we use a multimeter turned on in ohmmeter mode. IAC before starting the diagnosis must be disconnected from the on-board circuit. First of all, we measure the resistance between terminals A and B, after C and D. It should be within 53 ohms. Next, measure the resistance between A and C, B and D. Here it should tend to infinity. If the test results differ from the values given, the regulator is faulty, and most likely it is he who is guilty of the fact that your car starts and immediately stalls. The reason for the failure of the IAC can be either a break in one of the windings, or in the wear of the guides of the conical needle. In any case, it is better to replace it.
Possible carburetor malfunctions
And now let's talk about the problems with starting carburetor engines "nine". There are no sensors that affect the operation of the power system, but this does not mean at all that there are fewer problems with them. If you are sure that the ignition system is working, but your car starts up and stalls right away - the carburetor is the reason. Rather, one of its working elements, which is responsible for the engine idling.
It is recommended to start the test with the idle solenoid valve. This device more often than others leads to the fact that the VAZ- 2109 starts up and immediately stalls . It does not matter which carburetor is installed on the engine.
The easiest way to diagnose a valve is to disconnect-connect the device to the power cord with the ignition on. The clicks that occur when the positive lead is connected to the corresponding terminal indicate that the electromagnet is working properly. If the valve does not react in any way to the supply of electricity, you can safely throw it away. Naturally, installing a new one in its place.
Having unscrewed the electromagnetic valve, at the same time check up a condition of the fuel idle jet. If necessary, blow and rinse it with carburetor cleaning fluid. Clogging of the idle nozzle also negatively affects the engine without load.
To problems with starting the power unit leads and suction in the system of excess air. As a result, the fuel mixture is leaner, and the engine starts to intermittently, losing speed and power. Check the tightness of the system at the mounting points of the vacuum tubes leading to the distributor and brake booster, as well as the idle valve seat.
The car starts in cold weather and immediately stalls
Low temperatures can affect engine stability only when the fuel pump is faulty. Are you trying to start the engine in severe frost, it starts, but stalls after a few seconds? Try pumping fuel using the pump lever. If the situation has changed, look for a problem in the pusher. In addition to the fact that its gaskets can be worn out, which, moreover, become more severe in severe frost, he himself can be covered with hoarfrost. All this makes it difficult to move. As a result, the fuel enters the carburetor in a smaller volume, which, again, leads to depletion of the fuel mixture.