Basic information
On all carburetor models, the main parts of the power system are a Stromberg or Pierburg carburetor, a gas tank, a mechanical fuel pump, metal and rubber fuel supply and return lines, an air cleaner and a cartridge-type fuel filter (non-separable), fixed in the gas tank.
The gas tank is located in front of the luggage compartment inside the car.
With the help of a gasoline pump, fuel is supplied from the gas tank through the fuel filter. It travels through the fuel supply line to the carburetor's float chamber, where a float and needle valve control the level of fuel that is maintained in the chamber. Excess fuel is sent back to the fuel tank through the fuel return line.
Depending on the model, the air cleaner is located either on top of the camshaft cover or directly on top of the carburetor inlet. It contains replaceable paper and mesh filters. All models include a thermostatic damper mounted on the air cleaner. It allows outside air to mix with warm air from the exhaust manifold, which optimizes the temperature of the air entering the carburetor.
The type of carburetor installed on the car depends on the year of manufacture and the market of the car. Stromberg CDT 175 or Pierburg 2E-E carburetors can be installed.
On a Stromberg COT 175 carburetor, cold start fuel delivery and high idle are controlled by a temperature delay valve. It is a bimetallic plate that controls the supply of vacuum to the diaphragm of the air damper trigger. When a cold engine is started, the valve cuts off the vacuum supply to the diaphragm and the choke is held closed. As the bimetallic plate of the delay valve heats up during the flow of current when the ignition is turned on, the vacuum supply to the diaphragm of the starting device is gradually restored and the air damper opens. At the same time, the revolutions x.x. and the mixture quality returns to normal. A fuel shut-off valve is also installed; it prevents the engine from running when the ignition is turned off and prevents the engine from exceeding a predetermined threshold.
For certain markets, vehicles are equipped with Pierburg 2E-E electronically controlled carburetors. idle speed (x.x.) and mixture quality are controlled by throttle and choke actuators, respectively.
The operating parameters of the engine are monitored by a set of sensors and the entire system is controlled by an electronic control unit (ECU). At engine speeds higher than x.x. mixture quality is maintained by a choke actuator that changes the position of the choke and therefore the amount of air entering the carburetor. At speed x.x. or close to x.x. the actuator controls the mixture by changing the position of the needle inside the air speed correction jet x.x. This allows you to deplete or enrich the mixture entering the engine through the idle jet. The idle speed is controlled by the ECU and compared with the data stored in the electronic memory of the unit. With the help of the ECU, the idle speed is maintained at an optimal level under all engine operating conditions. The block regulates the position of the throttle valve using an actuator. Feedback is implemented using a throttle potentiometer (position sensor). The secondary functions performed by the actuators are engine braking when the shut-off valve is turned on, limiting the maximum engine speed and preventing the engine from running when the ignition is turned off.
Precautionary measures
Many of the operations described in this chapter involve disconnecting fuel lines, which may cause some fuel to leak. Parade start work carefully read the warnings above, and the information handed out "Safety first!" at the beginning of this book.
Warning: Gasoline is a very dangerous and volatile liquid, so no precautions should be taken when handling it. Ventilate the premises well when working with gasoline - open windows and doors to create a draft. Do not smoke and keep open flames or uncovered lamps near the work area. Remember. that household appliances such as heaters, water heaters, and hair dryers also pose a potential gasoline fire hazard. Always have fire extinguishing equipment on hand and familiarize yourself with the rules for their use before starting work. Protect your eyes when working on the power system and immediately wash off any gasoline that comes into contact with your skin with soap and plenty of water. Remember that gasoline vapors are just as dangerous as liquid gasoline; the canister from which the gasoline is drained contains gasoline vapors and is potentially hazardous.
Caution: Pay special attention to cleanliness when working with parts of the power system - dirt entering the power system can block the pipelines, which will lead to interruptions in engine operation.