Car engine diagnostic

To get started, you need to familiarize yourself with the engine construction, power systems, lubrication, cooling and ignition of carburetor engines. Examine mates and parts that affect engine performance. Learn to determine the structural parameters of the crank mechanism and valve mechanisms and engine systems of various technical conditions. Learn how to adjust the interface between the engine and its systems. Learn to determine the places and methods of connecting diagnostic tools to the engine and its systems. Have an idea of ​​the nature of changes in the structural parameters of the engine.

Diagnosis of the engine of a modern car consists of the following steps:

Diagnostics of car engine crankshaft;

Diagnostics of the timing of a car engine;

Diagnostics of the cylinder piston engine group;

Diagnostics of the fuel system of the car;

Car carburetor diagnostics;

Diagnostics of the car engine power system;

Diagnostics of the engine cooling system;

Diagnostics of the engine lubrication system;

Diagnostics of the engine ignition system.

The technical condition of the engine, the most complex and important unit, has the most significant impact on the performance of a car – performance, economy, speed, readiness for movement, the content of harmful substances in exhaust gases.

List of engine breakdowns

(Help you in diagnose your car)

Engine breakdownSignCause
Engine power reduction The engine under load does not develop revolutions, smokes heavily, does not have throttle response.

Deterioration of parts of the cylinder-piston group, interruptions in the ignition system, malfunctions in the power supply system, deposits in the combustion chamber, deposits in the intake and cooling systems, disruption of the gas distribution mechanism, damage to the cylinder head gasket. 
Increased engine oil consumption Oil leakage through the crankshaft oil seals, leaks in the crankcase sump joints, with covers, valve boxes, distribution gears, difference in the densities of the fuel pump and engine block connections, oil pipelines, wear or breakage of piston rings and grooves in the piston, coking of slots in the oil scraper piston rings, production of cylinders, the formation of rear or scratches on their surface, increased pressure in the crankcase due to the large number of gas and malfunctions in the ventilation system map a.

Increased fuel consumption

 Depreciation of the cylinder-piston group, malfunctions in the power and ignition systems.

Large clearance between valves and pushers

Knocks in the engine during operation

Violation of the adjustment of the gap between the valve stem and the pusher (rocker).

Depreciation of main and connecting rod bearings, piston pins and bushings

 The increased clearance between the bearings and the necks of the crankshaft, the wear of the cam gears, the increased clearances between the cylinder and the piston, between the piston bosses and the piston pin, the wear of the camshaft bearings, as well as the early ignition of the mixture, causing detonation (explosive) combustion of the working mixture.

Low oil pressure

Increased clearance in the bearings of the crankshaft, lack of oil or a decrease in its viscosity, overheating of the engine and oil, malfunction of the oil pump, violation of the adjustment of the pressure relief valve of the oil pump.
Water in the oil pan

Malfunctions in the engine during proper operation of the power and ignition systems.

Malfunction of the cylinder head gasket, weak tightening of the bolts and nuts of the studs of the cylinder head, cracks in the cylinder block and cylinder head.

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Author: delfi

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