Checking and repairing the EPH system of carburetor 2108, 21081, 21083 Solex

Design

EPHH carburetor VAZ 2109 includes the following components:

• Economizer;
• Solenoid valve;
• Throttle valve limit switch.

If at least one component of the EPHH design fails, the entire assembly stops working.

Element location

Operating principle

To determine the cause of the problem and take action to troubleshoot the EPHH, you need to know about the principle of its operation.

1. The economizer is equipped with output and input circuits.
2. The input circuits are a limit switch and a wire that connects to the switch.
3. The throttle (throttle) limit switch tells the economizer whether the gas pedal is depressed or not at that particular moment.
4. If the pedal is not depressed, the limit switch closes to ground.
5. As soon as the gas pedal is pressed by the driver, the contact is switched off.
6. The wire that connects the switch and the economizer reports the number of pulses to the ignition coil. In fact, due to this, the economizer is able to find out about the actual current speed of the power unit.
7. The EPHH has only one output circuit - the XX solenoid valve of the carburetor system (XX - idle speed). The economizer can turn this valve on and off.
8. Fuel economy is ensured by closing the XX fuel jet at high engine speeds.
9. If the gas pedal is not depressed, the throttle limit switch closes to ground, the speed is less than 2.1 thousand per minute, then the economizer opens the XX solenoid valve.
10. When the gas pedal is depressed, the limit switch opens, leaving the valve open anyway. The valve closes only when the engine speed exceeds 2.1 thousand per minute.
11. The valve is in the closed position until the speed drops below 1.9 thousand per minute.

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If the car is coasting with the gear engaged and the accelerator pedal released, the EPHH will not turn on, even if the revolutions drop below 1900 per minute. The economizer monitors the closed position of the damper. If the engine speed at idle is too high, it is perceived as coasting.

Actually, this is all you need to know about the operation of such an element as EPHH.

Practice and research show that the use of an economizer allows you to save about 5 percent of engine consumption.

Device

The VAZ 2109 carburetor consists of two main elements - the body and the cover. All parts are mainly located in the housing (pump, jets, float, etc.). Also, the power system, which may be associated with repairs, includes: candles, EPHH, and so on.

When the pump pumps fuel from the tank, it first enters the carburetor float chamber block. This chamber is also called the first or primary. It serves to maintain an optimal level of gasoline at which the carburetor can operate normally and maintain stable speed. At the entrance to the chamber, there is a special fitting through which fuel passes. Its quantity is controlled by the valve, as well as several floats. When you lightly press the gas pedal, the amount of gasoline entering the chamber, and accordingly its pressure, decreases sharply. In order for the flammable mixture to enter the chamber normally, at low pressure, the valve rises higher, clearing the way. This process is continuous and runs as long as the engine. The valve structure is closely connected to the float. This control scheme eliminates the chance of spark plug overflow.

When you sharply press the gas pedal, a large amount of fuel enters the primary chamber block. In order to protect the candles, there is a secondary chamber. It opens when the engine speed is high. The first chamber, with the accelerated movement of fuel, pours it into the second, and ensures a uniform, enriched mixture when it enters the cylinder, thereby preventing pedal failure.

For normal operation of the VAZ 2109 engine, simply gasoline is not enough. The carburetor must also receive air. It enters through the valve into the float chamber block, where it is mixed with fuel and forms a flammable mixture.

In addition to when the VAZ 2109 car is in motion, it can also be stationary, but with the engine running. Here a device such as idle speed is already triggered. It is regulated separately, supplying fuel through a solenoid valve to the float chamber. The idle control circuit includes an electronic device - an economizer. It activates the solenoid valve at speeds below 1700 rpm and deactivates when the gas pedal is pressed.

It is very important to know that food does not always pass through an economizer. Sometimes, the idle circuit bypasses this device, turning on the solenoid valve directly from the ignition.

Symptoms of a problem

There are several main signs indicating failure of the EPHH:

• The engine regularly stalls at idle;
• Detonation occurs in the engine when the ignition is turned off;
• The engine stalls when coasting braking is performed.

You can check whether the EPHH and its control unit are working correctly with your own hands. To check the valve, you should monitor its activation in various operating modes. Correct operation is determined by ear or using a voltmeter.

Valve check

There are three main steps to checking the functionality of the solenoid valve.

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In addition to the solenoid valve itself, you should also definitely check the EPHH control unit.

Plus and minus

Checking and repairing the economizer of power modes of the carburetor 2108, 21081, 21083 Solex

A faulty economizer of the power modes of the carburetor 2108, 21081, 21083 Solex on VAZ 2108, 2109, 21099 cars causes some loss in power and throttle response of the car engine (when the engine is running at full load), as well as an increase in fuel consumption (insignificant).

Possible malfunctions are damage to the diaphragm - leads to failure of the economizer and, as a consequence, deterioration in power, increased fuel consumption, clogging of channels and nozzles - also leads to failure and a drop in power, leakage of the ball valve - increases fuel consumption due to leakage from the economizer nozzle.

Checking the economizer of power modes of the carburetor 2108, 21081, 21083 Solex

As such, in general, it is impossible to check the operation of the power mode economizer. The deterioration in the performance of the car engine associated with it is difficult to notice. Therefore, it is necessary to remove the carburetor from the engine and check its channels, jets and diaphragm.

— Checking the tightness of the economizer system

We turn the removed carburetor over and press the rubber tube with one end to the outlet hole of its air channel.

We create a vacuum with our mouth or using a rubber bulb (suck in air). The drop in vacuum should not be observed for a long time (20-30 seconds). If it falls immediately, then the economizer housing is not sealed or its diaphragm is damaged.

The outlet hole of the air channel (vacuum supply channel) of the economizer of power modes of carburetors 2108, 21081, 21083 Solex

We are trying to restore the tightness of the case first by tightening the screws securing its cover. It didn’t help, remove the cover and change the aperture.

— Checking the tightness of the ball valve

We remove the economizer housing cover, the diaphragm with the spring, firmly attach the rubber tube to the valve and again create a vacuum in it. If the valve is in good working order, no drop in vacuum should be observed.

Elements of the economizer of power modes of carburetors 2108, 21081, 21083 Solex

— Checking the height of the pusher

A worn pusher on the economizer diaphragm greatly reduces its performance.

We measure its protrusion with a caliper. Must be at least 6 mm.

Measuring the height of the pusher on the economizer diaphragm of power modes of Solex carburetors 2108, 21081, 21083

Repair of power mode economizer

Repair of the power mode economizer consists of cleaning its jet channels, replacing the diaphragm, and eliminating deformation of the economizer housing cover.

— We clean the channels with thin copper wire and a pointed wooden stick. Before cleaning, you can pour a little acetone into them and let them sit for a while.

— We carry out cleaning through visible holes: the air channel, the fuel channel (by unscrewing the fuel nozzle), the ball valve (by pressing the valve ball and inserting the wire behind it).

After cleaning, blow everything out with compressed air (pump or compressor).

— We straighten the curved housing cover with a file.

Notes and additions

— The design of the economizer of power modes of carburetors 2108, 21081, 21083 Solex of VAZ 2108, 2109, 21099 cars, the location of its channels and elements can be seen in the article “Design of the economizer of power modes of carburetors 2108, 21081, 21083 Solex”,

“Scheme: economizer Solex 2108, 21081, 21083”,

principle of operation in the article “Principle of operation and operating procedure of the economizer of power modes of the 21073 Solex carburetor.”

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