Possible engine malfunctions, their causes and troubleshooting methods for Niva Chevrolet
Cause of malfunction
Remedy
The engine does not start
No fuel pressure in the rail:
- - clogged fuel lines;
- - faulty fuel pump; clogged fuel filter; faulty fuel pressure regulator
flush and blow out the fuel tank and fuel lines; replace the pump; replace the filter;
check the regulator, replace the faulty one
- The ignition system is faulty
See "Features of the Niva Chevrolet engine management system"
The engine runs unsteadily or stalls at idle
- Insufficient fuel pressure in the engine fuel line ("ramp")
See «Engine won't start»
- Idle speed control valve is faulty
Replace the idle speed control valve, article - Idle speed control valve Niva Chevrolet
- Air is sucked in through the engine crankcase ventilation hoses and the hose connecting the intake manifold to the brake booster
Tighten the mounting clamps, replace damaged hoses
- Clearances between the levers and camshaft cams are violated
Check the hydraulic mounts, replace faulty ones
- Ignition system is faulty
See "ECU sensors Niva Chevrolet"
The engine does not develop full power and does not have sufficient throttle response
- Incomplete throttle opening
Adjust throttle actuators
- Throttle position sensor is faulty
Replace sensor
- Insufficient fuel pressure in the engine fuel line ("rail")
See «Engine won't start»
- Air filter is dirty
Replace the filter element
- Ignition system is faulty
See "Engine management system"
- Clearances between levers and camshaft cams are violated
Check hydraulic supports, replace faulty ones
- Insufficient compression - below 1 MPa (10 kgf/cm 2):
- Blown cylinder head gasket;
- Piston burnout, broken or stuck piston rings; poor valve seat fit;
- excessive wear of cylinders and piston rings
Do the following:
- replace the gasket;
- clean the rings and piston grooves from carbon deposits, replace damaged rings and pistons;
- replace damaged valves, grind the seats;
- replace pistons, bore and hone the cylinders
Knock of crankshaft main bearings
Usually a dull, metallic knock.
It is detected when the throttle valve is opened sharply at idle.
Its frequency increases with increasing crankshaft speed shaft.
Excessive axial clearance of the crankshaft causes a knock that is sharper with uneven intervals, especially noticeable with a smooth increase and decrease in crankshaft speed
- Insufficient oil pressure
See "Insufficient oil pressure at idle"
- Loose flywheel mounting bolts
Tighten bolts to recommended torque
- Increased clearance between journals and main bearing shells
Grind journals and replace shells
- Increased clearance between thrust half rings and crankshaft
Replace thrust half rings with new ones or thicker ones
Knocking of connecting rod bearings
Usually the knocking of connecting rod bearings is sharper than the knocking of main bearings. It can be heard at idle speed of the engine when the throttle valve is opened sharply.
The place of knocking can be easily determined by disconnecting the spark plugs one by one
- Insufficient oil pressure
See "Insufficient oil pressure at idle"
- Excessive clearance between the crankshaft journals and the bearings
Replace the bearings and grind the journals
Piston knock
This knock is usually not ringing, muffled; is caused by the piston "beating" in the cylinder.
It is best heard at low engine speeds and under load
- Increased clearance between pistons and cylinders
Replace pistons, bore and hone cylinders
- Excessive clearance between piston rings and piston grooves
Replace rings or pistons with rings
Knocking of intake and exhaust valves
Operating with increased clearances in the valve mechanism causes a characteristic knock, usually at regular intervals; its frequency is lower than any other knock in the engine, since the valves are driven by the camshaft, the rotation speed of which is two times less than the crankshaft rotation speed
- Increased clearance y between the levers and the camshaft cams
Check the hydraulic supports, replace the faulty ones
- Valve spring failure
Replace the spring
- Excessive clearance between the valve stem and the valve guide
Replace worn parts
- Camshaft cam wear
Replace the camshaft and valve levers
Excessive noise of the camshaft drive chain
From the general engine noise, the noise of the camshaft drive chain stands out when gaps appear between the engagement elements and is clearly heard at low crankshaft speed
- The chain has weakened due to wear
Replace the chain
- Shoe failure chain tensioner or damper
Replace the tensioner shoe or damper, article - Niva Chevrolet damper replacement
- The hydraulic chain tensioner is faulty
Replace the hydraulic tensioner, article - Replacing the Niva Chevrolet tensioner
Insufficient oil pressure at idle on a warm engine
- Foreign particles getting under the oil pressure reducing valve
Clean the valve from foreign particles and burrs, flush the oil pump
- Worn oil pump gears
Repair the oil pump
- Excessive clearance between the liners and the main journals of the crankshaft
Grind the journals and replace liners
Excessive oil pressure on a warm engine
- Seizure of the oil pressure relief valve
Replace the valve
Increased oil consumption
- Oil leaking through engine seals
Tighten fasteners or replace gaskets and seals
- Wear of piston rings and pistons or engine cylinders
Bore out the cylinders and replace the pistons and rings
- Broken piston rings
Replace the rings
- Coking of oil scraper rings or slots in piston grooves
Clean the slots and rings from carbon deposits
- Wear or damage to oil scraper caps valves
Replace valve stem seals
- Increased wear of valve stems or guide bushings
Replace valves, repair cylinder head
Increased fuel consumption
- Increased resistance to vehicle movement
Check and adjust tire pressure, brake system, wheel alignment
- Faulty ignition system
See "Engine management system"
- Faulty injectors
See "Checking and replacing Niva Chevrolet injectors"
- Fuel leakage in pipe connections
Tighten pipe connections
- Using low-quality fuel
Fill with recommended fuel
Engine overheating
- Weak tension of the pump and generator drive belt
Adjust the belt tension
- Insufficient amount of fluid in the cooling system
Add coolant to the cooling system
- The outer surface of the radiator is heavily contaminated
Clean the outer surface of the radiator with a stream of water
- The thermostat is faulty
Replace the thermostat, article - "How to replace a thermostat"
- The radiator cap valve is faulty, the opening pressure is less than 0.05 MPa (0.5 kgf / cm 2)
Replace the cap
The coolant pump is faulty
Check the operation of the pump, replace it or repair it, see the article - "How to replace a water pump"
Fast drop in the liquid level in the expansion tank
- Damaged radiator
Repair the radiator or replace
- Damaged hoses or gaskets in the pipe connections
Replace damaged hoses or gaskets
- Liquid leaking from the heater tap
Replace the tap
- Loose hose clamps
Tighten the clamps
- Liquid leaking through the coolant pump seal
Replace the seal
- Damaged radiator plug or gasket
Replace the plug
- Damaged cylinder head gasket
Replace the gasket, article - "Replacing the cylinder head gasket"
- Fluid leaking through microcracks in the block or in the cylinder head
Check the tightness of the block and cylinder head, if cracks are found, replace the damaged parts
- Fluid leaking through microcracks in the housing or cover of the coolant pump, expansion tank or inlet pipe
Check the tightness, if cracks are found, replace the damaged parts; minor leaks can be eliminated by adding a sealant such as NIISS-1 to the coolant