Many drivers still remember the VAZ-2107 and VAZ-2108, equipped with both carburetors and the first injection systems. The appearance of injection on Zhiguli engines in the 1990s was seen as a major technological leap—a real breakthrough in domestic engine building. At the time, it seemed that the era of carburetors was coming to an end. However, the enthusiasm of owners of injection "sevens" and "eights" faded noticeably quickly.
Practice showed that everything was much more complicated than described in automotive magazines and by specialized experts of that time.
Reliability: The Weak Spot of Injection
The main problem with injection systems was obvious—low reliability. Owners couldn't constantly put up with injection failures, and the situation was aggravated by the fact that in those years there was an acute shortage of both spare parts and specialists capable of properly servicing such systems. Repairs often turned into waiting in line.
Even after the domestic industry was able to significantly improve the quality of electronics and the injectors themselves, the wary attitude towards injection did not disappear. The distrust, once established, stuck for a long time.
At the same time, owners of carburetor cars looked at the new Zhigulis with injection with a certain envy. It seemed that the engine ran smoother, pulled more confidently, and, most importantly, consumed less fuel.
What Injection Really Did Better
From a technical point of view, injection had undeniable advantages. It dosed the fuel supply much more accurately, taking into account the load, RPM, and air temperature. This ensured an almost perfect engine start and stable idling.
It was with these modes that Zhiguli engines traditionally had difficulties. Even relatively new carburetors with an EPHH solenoid valve initially worked properly, but problems started after two or three years. It was necessary to regularly disassemble the system, flush the needle and jets, and clean the channels. In the end, it often ended with the solenoid valve simply being shut off.
Paradoxically, this is where the key advantages of the injection system ended. Then the disadvantages began.
Carburetor: Resource Proven Over Decades
The statement that a Zhiguli carburetor could work for decades sounds somewhat exaggerated, but it is not far from the truth. The real service life of a carburetor system on VAZ engines could reach twenty years.
Yes, the carburetor required periodic maintenance: cleaning the jets, removing debris from the filter, adjusting the fuel level in the chamber. However, structurally it hardly changed. In rare cases, it was necessary to replace gaskets or tighten the throttle cable.
Over time, of course, the bushings of the throttle valve axes wore out, but this problem was also successfully solved by repair.
The injection system looked much less hardy in this regard. Injectors could fail even at the engine break-in stage. They could not be repaired—at most, a high-quality flush. More often, it was about replacement, which was usually carried out simultaneously with the replacement of the fuel filter. In addition, the operation of the injector directly depended on the electronic control unit and several sensors, the reliability of which left much to be desired.
The carburetor, in fact, had only one external parameter affecting its operation—the vacuum in the intake manifold. And if problems arose, they most often came down to a violation of the tightness of the vacuum tube.
It is also important that the design of the carburetor was honed over decades of real operation. All typical malfunctions and ways to eliminate them were well known. Moreover, almost any driver could fix the problem—even right on the road.
Responsiveness and Fuel Consumption
The only thing that carburetor systems really lacked was responsiveness. An injection engine, as a rule, responded to pressing the gas pedal a little faster. However, it is worth considering here that carburetors were designed with low-quality gasoline in mind. And even in the presence of water or small contaminants, they continued to work.
Dirty gasoline did not become a critical problem: the carburetor was purged, the filter was changed, the contaminated fuel was drained and replaced with clean fuel from a canister. The injector, on the other hand, could fail after the first trip if low-quality fuel was used.
Some elements of the carburetor system, such as the idle circuit, required increased attention—especially if the car had been idle for a long time. In rare cases, it was enough to pump gasoline or blow out the jet with a pump. But in general, for normal operation, the presence of fuel in the primary chamber was usually enough.
In certain modes, including idle, the carburetor could work no worse than the injector. Here, a lot depended on the driver's skills. If the fuel consumption in the injection system was calculated by the electronic control unit, then in the case of the carburetor, it was necessary to correctly set the position of the throttle valve.
From an economic point of view, the carburetor lost to the injector mainly at idle and in first gear. Nevertheless, there were enthusiasts who experimentally adjusted the carburetor so that fuel consumption did not exceed the rated values.
The injector in this sense was much more demanding. Any intervention—even a simple flushing of the rail and injectors—required subsequent adjustment and calibration of the system. It was almost impossible to perform such work in a regular garage, so servicing the injector was logically shifted to professionals.