On a VAZ 2109, the carburetor fails when you press the gas - reasons

Carburetor or injector

While the whole world has made a choice in favor of injection engines, in our country the intensity of the debate on the topic “injector or carburetor” does not subside. Mostly, the debate revolves around the possibility of field repair of an engine with a carburetor or an injector. Adherents of the first passionately prove that a failed carburetor engine can be easily repaired literally “in the open field.” And if the injection engine fails, prepare a tow rope and go to the service center.

Proponents of injectors raise the objection that injection engines break down much less often, and there are only two typical malfunctions.

1. Damage to the crankshaft position sensor.
2. Fuel pump failure.

At the same time, the “injection guys” rather sarcastically clarify that the fuel pump can just as easily break down on a carburetor engine, and the sensor costs a penny and can be easily changed even in the field. Perhaps we should admit that the supporters of injection are somewhat right. But if you happen to drive a carburetor version, then you shouldn’t chase the illusory savings of a glass of gasoline per 100 kilometers. You shouldn’t start switching to a new type of power system just because the VAZ 2109 carburetor failed when you pressed the gas pedal.

If something happens, the carburetor “nine”, even if it sneezes in blue puffs, even with a sinking accelerator pedal, will take you home - after all, it’s worth something.

Let's sum it up

So, we see that a car can jerk for many reasons. As a rule, it helps to alternately replace consumables (filters, spark plugs, armored wires) and clean the injector nozzles. It is better to entrust the check of electronics and sensors to a specialist at a service station.

Often the problem can also lie in the transmission; the car also “jumps” in this case - especially with an automatic transmission, although manual transmissions are also prone to failure. In a manual transmission, replace the basket and/or clutch disc.

The automatic transmission checks the oil for its level and quality. Please note that qualified repair of an automatic transmission “in a garage” is impossible; it must be diagnosed at a service station.

Ozone or Solex

With the start of production of the VAZ 2108 and 2109, AvtoVAZ designers abandoned the use of Ozone carburetors, in which many complex options had no practical meaning. What was the cost of the forced idle economizer alone, which supposedly served to save fuel during engine braking? Neither engine braking became widespread, nor did the EPKH bring any noticeable savings, but it provided drivers with quite a few headaches when pressing the gas.

When switching to “eights” and “nines”, the plant returned to a simpler version of the carburetor. It was distributed under the name Solex: after the name of the French company that produced its prototype. Solex lost the pneumatic drive for the secondary chamber damper, a semi-automatic starting device, and an autonomous idle system.

The design has been simplified and reliability has increased. It is Solex that, as a rule, owners of carburetor versions of the VAZ 2109 deal with.

Video - Why the engine speed fluctuates at idle

The occurrence of the above malfunctions is a consequence of violations of the operating conditions defined by the manufacturer, or the negative impact of external climatic factors: high humidity, abnormally high (low) temperature values ​​or its sharp fluctuations.

In addition, it must be taken into account that the reason for the incorrect functioning of the “nine” carburetor may be a malfunction of the vehicle’s power system, ignition system, or a clogged air filter.

Depending on the type of VAZ engine, there are different types of reasons. Let's start with carburetor cars of Soviet and Russian production VAZ 2107 and VAZ 2109.

In a situation where the reason that the VAZ 21099 (carburetor) has variable speed is due to incorrect adjustment, the vast majority of car enthusiasts, especially those with little practical experience, prefer to use the services of professional auto mechanics. However, you can perform this operation yourself, using the instructions presented below. As an example, let's look at the technology for adjusting the idle speed of the Solex carburetor, which is the most common on the VAZ 2109 and VAZ 21099 models.

The objects of adjustment are the screws that regulate the “quantity” (Figure 1, position 1) and “quality” (Figure 1, position 2) of the combustible mixture, and the working tool is a screwdriver with a flat blade and an external tachometer, which makes it easy to take readings.

Picture 1

Non-carburetor causes of engine failure

Car owners usually refer to failures as unpredictable short-term interruptions in the operation of a car’s internal combustion engine. Failures belong to the category of so-called “unreasonable”, or, more precisely, multi-cause failures. It is impossible to say unequivocally about such breakdowns: failures appear - change the spark plugs. More precisely, it is possible to say, but it is not a fact that after replacement the failures will disappear. Although this also happens.

So failures in the operation of a carburetor engine are not necessarily related to the device itself. And before you start working on such a complex unit, you should exclude the influence of other reasons.

1. Mechanical failure of the drive.
2. Ignition system malfunctions.
3. Failures of the power system located outside the carburetor.

These groups of negative factors stand out among others. Let's look at them in detail.

Remove the outlet pipe from the fitting. Press the fuel pump manual drive lever vigorously. There should be an intense stream of fuel coming out of the hose. If not, the pump is faulty and must be repaired or replaced. Clean the fuel line filters from the tank to the carburetor, and blow out the pipelines themselves.

If everything is in order with the power and ignition systems, move on to the carburetor itself.

Let's sum it up

So, we see that a car can jerk for many reasons. As a rule, it helps to alternately replace consumables (filters, spark plugs, armored wires) and clean the injector nozzles. It is better to entrust the check of electronics and sensors to a specialist at a service station.

Often the problem can also lie in the transmission; the car also “jumps” in this case - especially with an automatic transmission, although manual transmissions are also prone to failure. In a manual transmission, replace the basket and/or clutch disc.

The automatic transmission checks the oil for its level and quality. Please note that qualified repair of an automatic transmission “in a garage” is impossible; it must be diagnosed at a service station.

VAZ 2109 carburetor malfunctions

The carburetor is one of the most delicate components of the VAZ 2109 car to configure. Its repair requires experience. The maximum that an amateur can handle is replacing the throttle cable of a VAZ 2109. Many subtle technologies interact with each other in the process of preparing the air-fuel mixture. By adjusting the operation in acceleration mode, you risk disrupting the idle speed adjustment, and vice versa. So you should start repairing the carburetor yourself with caution and without excessive self-confidence.

A significant volume of fuel with all impurities, chemical and mechanical inclusions, conceivable and inconceivable contaminants passes through the carburetor. This means that cleaning will never harm the carburetor. It is about total cleaning that we will talk about.

Everything is cleaned, including fuel injectors, air jets, transition channels, filter elements and metering wells. This is done like this:

• disconnect the mechanical throttle actuator;
• separate the inlet and outlet fuel pipes;
• wrap the freed carburetor with aluminum foil of sufficient width;
• place the wrapped carburetor in a plastic bucket to protect it from leaking;
• fill the carburetor with acetone or other strong solvent;
• leave the carburetor in a flooded state for a day.

Keep in mind that this should be done in a well-ventilated non-residential area. At the end of washing, drain the solvent, rinse the unit with a running stream of solvent, blow with a stream of compressed air, and dry. Install the carburetor in its original place. Try your "nine".

If a radical flush solves the problem, ride to your heart's content. If you haven’t decided, it’s time to turn to professionals. Forget about engine failures for a while and go to a car service center.

Failure in transient modes on Solex

Frequently encountered problems when pressing the accelerator pedal of a carburetor engine are the so-called “failure”, “jerk”, “twitching” and “swaying”.

A failure is when, when adding gas when starting or accelerating a car, sluggish engine operation is observed, a slow increase in speed up to a deceleration lasting from half a second to several seconds.

A jerk is the same failure, but shorter, up to half a second.

A twitch is a series of several jerks.

Swinging - several failures following one after another.

It is worth noting that before eliminating these malfunctions by changing the settings of the carburetor itself or disassembling it, you need to make sure that the reason lies precisely in it. The technical condition of the engine is of great importance. Incorrect installation of the gas distribution mechanism, wear of the camshaft, incorrectly set ignition, violation of compression in the cylinders: too low or unacceptably different in different cylinders. All this disrupts the normal operation of the engine, increases fuel consumption, and leads to clogging of the carburetor with deposits and resins.

It is also necessary to check the fuel supply system to the carburetor for blockages in the fine filter, the fuel pump strainer, the fuel intake, the tightness of the fuel pump, as well as the ignition system. At idle or at low loads, the engine can operate normally, but when the load increases, disturbances in the fuel supply may appear.

We will assume that the ignition, gas distribution, cylinder and fuel supply systems are fully operational and the reason lies in the carburetor. Let's consider the possible causes of dips and jerks in the Solex 21083 carburetor and ways to eliminate them:

Dips when starting - The outlet of the transition system is clogged.

Adjusting the ignition angle

Sluggish acceleration of the car and instability of the idle speed are also often associated with incorrectly set ignition; this procedure is mainly carried out in car repair shops using special equipment. But if you wish, it’s easy to make the adjustment yourself, and without a strobe, and quite accurately:

• with the engine stopped, loosen the three nuts securing the distributor (the third fastening is located at the bottom, it is not visible from above);
• we start the car, turn the distributor-distributor clockwise (to “+”), and if the ignition was late, the idle speed will increase noticeably;
• we select the optimal position of the distributor (the operation of the internal combustion engine should be smooth, without failures), reduce the speed using the quantity screw, turn off the engine, fix the distributor-distributor with one nut for now, and check the results of the ignition adjustment on the fly.

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If, under heavy load and sharp acceleration, your fingers begin to noticeably “knock” (engine detonation appears), you should move the distributor a little to “minus”, then check the car again while driving. This way you can set the ignition quite accurately, and sometimes even better than with a strobe light.

Holes for Solex carburetor transition systems

The size of the holes can decrease over time due to deposits reducing fuel flow and leaving the mixture lean. To clean the holes in the transition systems, you will have to remove the carburetor, turn it over and clean it with a sharp stick or copper wire (it is impossible to clean the holes with anything harder than the carburetor material to avoid damaging the holes), rinse with acetone and blow out.

Low fuel level in the float chamber. This situation makes the fuel mixture leaner. To find out the fuel level in the chamber, let the engine run for a while, then remove the upper half of the carburetor and measure the fuel level, for example, with a caliper; for Solex 21083 the level should be 29 ± 1 mm. Gasoline tends to evaporate quickly, so remove the cap and take a measurement quickly. The needle valve may stick, thereby interfering with the flow of fuel into the float chamber; you can return the needle to its place by gently tapping, but it is better, of course, to replace it. If the fuel level is not correct, adjust the float mechanism.

Leaky tube supplying vacuum to the ignition vacuum corrector. Check the tube for cracks and breaks; the tube should fit tightly onto the appropriate fittings; replace the tube if necessary.