But having changed the car to a more modern one, many motorists continue to turn to the same masters. And they lack the courage to admit that they do not understand the complex processes in fuel systems and electronic ignition circuits. They watch the spark for a breakdown, while breaking through transistors, the insulation of the bobbin windings, high-voltage wires, and "blazing" conductive paths on the covers and runners of the distributor. Without solving the problem, such mechanics drive "disease" inside. And in the end, the owner still goes to professionally trained engineers. But "treatment" machines are already much more difficult.
Specialists often find themselves in a situation where, after a long work, even with the help of instruments, nothing can be understood. And only after a while it turns out that the previous "smart ass" twisted the jets in the carburetor or twisted everything in the injector, and at the end violated its tightness or burned the pressure sensor.
The list of possible causes leading to increased fuel consumption and reduced power is very rich. And besides them, there are a number of uncharacteristic, but often occurring problems, such as piston burnout, fuel getting into oil, failure of one of the injection system temperature sensors, thermostat failure, entanglement of vacuum tubes, destruction of one of the carburetor gaskets, piston rings or piston baffles.
Diagnostics must be carried out without disassembly, since otherwise there is a great chance to eliminate the consequence only for a while or even supplement the existing problem with new, sometimes more complex ones.
For example, there are a lot of reasons leading to a decrease in spark power. If diagnostics are performed on a multifunctional motor-tester, on its screen you can immediately determine which defect is present. In any other way, it is impossible to assess the conformity of the form of the sparking process with the one in which complete combustion of the fuel occurs in various operating modes.
A common situation is when, having found signs of abnormal operation in the engine, a motorist goes to a mechanic. He, having measured the engine compression and found compliance with the norm, begins to regulate both the carburetor and the ignition system, achieving stable operation. Sometimes it succeeds. The engine starts up regularly, stops stalling, but at the same time, traction and fuel consumption leave much to be desired. Where is the mistake?
In a worn engine, valve seals often leak. The oil flowing onto the pistons leads to artificial compensation of the gaps that have arisen due to wear of the pistons, rings and cylinders. And when measuring compression, false readings are obtained. Fixing this problem after "repair", made by a mechanic, is significantly difficult due to the need to restore the original adjustments.
The reverse situation is also quite common, when the owner is unjustifiably "plunge" in a major overhaul, although it would be enough to replace the same seals, which is more than 10 times cheaper.
Unfortunately, until now, the car maintenance market remains approximately equally divided into stations that meet modern requirements for qualifications, technical and cultural services, and fragments of the sadly memorable Soviet car service. Therefore, car owners should carefully familiarize themselves with the technical center in the pit of which they put their car. And not so much with the cost of services, but with how, with what and in what conditions the car will be diagnosed and repaired.