First of all, the evaluation «playfulness», or, as experts say, traction and speed qualities, can be objective and subjective. The criteria for an objective assessment are the maximum speed of the vehicle measured with the help of instruments and the intensity of its acceleration, primarily the acceleration time from a standstill with gear shifting to a certain speed. The criteria for subjective evaluation are much more complicated; for example, in different cars we feel the same intensity of acceleration in different ways depending on the strength of noise and vibrations in the cabin, the nature of the change in engine noise with an increase in the speed of its shaft, the clarity of gear changes and the stroke of the shift lever, the stroke of the accelerator pedal and the nature of its connection with axes of carburetor throttle valves. It can immediately be noted with satisfaction that cars «Zhiguli» have sufficient «playfulness» from an objective and subjective point of view. You just need to keep in mind that a high-speed engine «Zhiguli» and transmission designed for it «do not like» driving with a low number of revolutions, which means that when accelerating the car, you need not rush to switch to the next, higher gear, and when reducing speed while driving, turn on a lower gear in a timely manner, preventing jerks in the transmission. So, for example, in fourth gear, you should not drive at a speed of less than 50 km / h in a VAZ-2101 car and less than 45 km / h in a VAZ-2103 car.
«Appetite», or the fuel efficiency of a car, is characterized by fuel consumption per unit of distance traveled in various driving conditions; in general, it is estimated by the operating costs of fuel.
It must be borne in mind that the reference fuel consumption given in the technical data of the vehicle refers to the case of driving a fully warmed-up vehicle with a full load in the summer on a straight, level road with an improved surface in top gear at a constant speed of 80 km/h. In everyday operation, the conditions, even in the most favorable cases, are much more difficult; for example, the road, as a rule, has ups and downs and turns, there are obstacles in the way of movement, forcing to slow down, brake, accelerate again, shift down gears, etc. Therefore, although in real conditions the car is usually not fully operated, and with a partial payload, the operating fuel consumption is always higher than the control one, and the latter is used only to check the technical condition of the vehicle (hence its name).
Car fuel operating costs «Zhiguli» various models are given in table. 1.
It is useful for motorists to know that the following operational fuel consumption standards are established for state-owned VAZ vehicles:
- on the VAZ-2101 - 10.0 l / 100 km;
- on the VAZ-2102 - 10.3 l / 100 km;
- on the VAZ-2103 - 10.5 l / 100 km.
Operating fuel costs are highly dependent on specific driving conditions and driving style; they should be constantly monitored according to the diary of operation and maintenance of the vehicle.
Let us now consider what needs to be done to restore the high traction and speed qualities and fuel efficiency of the car, if they have decreased during operation. Let us keep in mind that, since cars «Zhiguli» have high durability, you can be sure that such phenomena, even with very significant runs, are not a consequence «old age» vehicle and engine, but a consequence of the occurrence of specific, usually easily remedied malfunctions. It can be said with certainty that traction and speed qualities and fuel efficiency can be maintained at a high level until the engine is put in for repair due to severe wear of the piston group, which caused excessive oil waste, which usually occurs only at runs far exceeding 100 thousand km.
Consider the main reasons that can lead to a decrease in traction and speed qualities, bearing in mind a run-in car without obvious signs of malfunctions (interruptions in the engine, knocks in it, etc.). In this case, the main reasons may be:
- incomplete opening of the throttle valves when the accelerator pedal is fully pressed;
- malfunction of the carburetor accelerator pump;
- incorrect fuel level in the carburetor float chamber;
- incorrect ignition timing;
- increased vehicle rolling resistance.
The last three reasons also lead to a deterioration in fuel efficiency.
Methods for ensuring that the carburetor throttles are fully open are described below in the section «Features of maintenance and current repair», and the fuel level settings in the float chamber - in the car's operating instructions. We only add that it is convenient to check the distance between the float and the gasket, as well as the size of the float stroke, using a home-made caliber in the form of a parallelepiped, one side of the section of which has a size of 7.5, and the second - 15.5 mm. It must also be borne in mind that the distance between the float and the gasket should in no case be more than 7.5 mm, as this will lead, during intensive acceleration, high speeds and overcoming long climbs, to sudden engine malfunctions due to exhaustion. fuel supply in the float chamber. At the same time, during operation, the fuel level tends to constantly increase, so it must be periodically checked and adjusted.
The accelerator pump test method was described above in the section «You are on your way», however, there it was an integral part of checking the power system in the event of an engine stop during movement. In the case under consideration, when the engine is running, but does not provide the required acceleration intensity, the absence of a stream of gasoline during the same test will indicate a failure of the accelerator pump itself; the usual easily remedied cause in this case is grazing the roller of the lever 1 of the accelerator pump drive (pic. 5) behind the carburetor float chamber tray, due to which the lever remains in the depressed position. Second (less likely) the cause is a rupture of diaphragm 2, which in this case must be replaced.
Pic. Fig. 5. Accelerator pump: a - diagram; b - view of the carburetor from the side of the accelerator pump:
1 - lever drive pump-accelerator; 2 - accelerator pump diaphragm; 3 - housing of the emulsion jet of the idle system.
The ignition timing is determined by the position of the body of the breaker-distributor, its shaft and the adjusting nut of the octane corrector. The procedure for the initial setting of the ignition timing is set out in the vehicle's operating instructions. The position of the body of the breaker-distributor relative to its socket is fixed when installed at the factory with a spot of paint, and there is no need to change it in operation; so you should check if the case is installed «on the spot» and, if it is not, restore its correct position. Just in case, it is useful to know that turning the breaker-distributor body counterclockwise leads to an increase in the ignition timing, and vice versa. «Thin» adjustment is performed by turning the adjusting nut of the octane corrector; normal is the position of the latter in the interval between zero and the third division towards earlier ignition (to the side «+»).
Increased rolling resistance of the car is most often the result of low inflation pressure in the tires, excessive tightening of the front wheel bearings, incomplete release of the foot or more often hand brake, and incorrect toe-in of the front wheels. To make sure that there is no increased rolling resistance, you should first check the internal air pressure in the tires and, if necessary, bring it to normal, eliminating this factor. Then you need to warm up the car engine, drive it for at least 15 km, find a small horizontal area with asphalt or cement concrete pavement in good condition, stop on it, open the driver's door, drive off and immediately release the accelerator pedal, simultaneously disengaging the clutch and leaving it in this position until the car comes to a complete stop (it is enough if the latter rolls by inertia only 2-3 m). In this case, looking through the open door at the road surface, make sure that the car rolled back at least 3-5 m after a complete stop. If this did not happen, one of the remaining causes of difficult rolling should be found and eliminated, which were mentioned above.
Let us now consider the causes of various malfunctions in the engine.
The occurrence of vibration («shaking») an engine with a frequency proportional to the number of revolutions, accompanied by a noticeable deterioration in the dynamic qualities of the car, is usually associated with a high-voltage wire jumping off one of the candles or with its failure. To find a defective candle, when the engine is running at low idle, one by one remove the high voltage wire from each of the candles (in order to avoid unpleasant electric shocks, it is better to remove and put on the wires with the engine off); that candle will be faulty, the disconnection of which did not entail an additional reduction in speed. A faulty spark plug can sometimes be found «to the touch» by its lower temperature compared to serviceable candles. You can also turn the candles out of the engine one by one and inspect their electrodes; the electrodes of a faulty spark plug will, unlike others, be covered with black soot, sometimes wet. A defective spark plug must be replaced. Sometimes, however, it does not stop its work completely, but partially (only under load, at high speeds or intermittently); in this case, it becomes difficult to detect it according to the signs described above, and the defect should be eliminated by alternately replacing one of the working candles with a known-good spare and each time checking the result of the replacement by moving in normal modes for several minutes.
At «uneven» engine malfunctions, it is necessary to check the ignition system in the same way as recommended above.
In cases of interruptions at high speeds, including in engine braking mode, the cause is usually a malfunction of the distributor contacts.
In the event of sudden failures at the end of a long, hard acceleration, long climbs with a heavy engine load, and driving at high speeds, the cause is most often a too low fuel level in the carburetor float chamber. At the same time, excessively high levels are one of the most common causes of increased fuel consumption.
Traction and speed qualities noticeably deteriorate, and fuel consumption increases if the ambient temperature is not appropriate for the season, or rather, the ambient temperature, the position of the air filter cover; should be placed in the position «winter» at temperatures below +5°C, and vice versa.
Often, despite the presence of a special control light, the cause of a sharp deterioration in the dynamics of the car is the hand brake, «forgotten» in an incompletely released position.
If a fully warm car starts badly «to pull», and this is accompanied by the appearance of a smell of gasoline in the cabin and deterioration of the engine at low idle speeds, the most likely reason is a spontaneous increase in the fuel level in the float chamber, which occurs regardless of its previous adjustment, which is associated with jamming of the locking needle in the lowered position or more often loss of tightness of the carbon valve. The latter, if it occurs even to a small extent, is also a hard-to-diagnose reason for the deterioration in the fuel efficiency of a car.
To check, you need to remove the cover of the float chamber and float 4 (pic. 6), remove the shut-off needle 3 and unscrew the needle valve. Then you should put a rubber hose 15-20 cm long on the thread of the valve, turn the valve upside down, insert the locking needle and, putting the other end of the hose on the tip of a squeezed small rubber bulb, check whether the bulb will gradually fill with air. If this happens, the needle valve has lost its tightness and must be replaced complete with the needle and the gasket underneath. In the absence of a replacement, the performance of the previous valve can be restored for a while by «tapping» locking needle. To do this, the valve must be clamped in a vise with the hole up, insert the needle and, without turning it, lightly hit through the wooden gasket on its end, into which the ball is inserted (do not hit hard, as this will lead to the loss of mobility of the ball). Then you should check the tightness of the needle valve and, if it is restored, install it in place.
An important element of the normal operation of the engine is its stable operation at low idle speeds. The procedure for adjusting the idle system is described in the instructions attached to the car, but sometimes the adjustment does not help and the engine immediately stalls when the accelerator pedal is released. Most often, the cause of this situation is clogging of the emulsion jet of the idle system. Therefore, in this case, it is necessary to unscrew the body 3 of this jet (see fig. 5), which is more convenient to do after removing the air filter housing, remove the jet from the housing and blow it thoroughly with a pump. In the carburetor of a VAZ-2103 car, the jet must be unscrewed together with the solenoid valve into which it is inserted, removed and blown through.
Let us especially consider the question of the rational warm-up time of the car before starting off after a long parking. Studies have shown that the amount of starting wear depends mainly on the number of piston strokes during the time until the engine warms up, and not on the load of the latter. Since the engine naturally warms up faster under load, it is more correct not to warm it up on the spot at idle, but to move off 20-30 seconds after starting and warm up while driving. In this case, of course, you need to drive slowly and not give the engine high speeds. This is even more true for cars «Zhiguli», whose engines run on oils that remain fluid at low temperatures, have an anti-drain valve in the oil filter that prevents oil from draining into the sump after the engine is stopped, and a carburetor that provides the car with satisfactory traction and the engine - stable operation at low idle almost immediately after a cold start. Switching to a short warm-up time will not only reduce starting wear on the engine, but also save you time, reduce fuel consumption and reduce air pollution in the parking lot.