The situation when engine-troit The Niva Chevrolet, which is familiar to many owners of this SUV, suddenly loses traction, fuel consumption increases, and the exhaust pipe begins to come out of black smoke with characteristic cottons. The engine works unevenly, vibrations on the body become noticeable even when idling. For an injector engine VAZ-2123 or more modern versions, this is a signal of a serious failure in the ignition system or fuel supply.
This behavior of the power unit cannot be ignored. Prolonged work with the failure of the ignition of the mixture in one or more cylinders leads to rapid failure of the catalytic converter and destruction of the piston group due to the entry of unburned gasoline into the oil. In this article, we will discuss in detail the main causes of unstable operation. Niva Chevrolet and methods of their elimination on their own in garage conditions.
Diagnosis: How to identify a problem cylinder
Before you change parts, you need to know exactly which cylinder is not working, and it's hard to hear that, especially if you have a periodic three, and the easiest and most effective way for injectors is to turn off the nozzles or coils in turn when the engine is running, and if you take the nozzle plug off the coil or the nozzle, the nature of the engine doesn't change, you've found the culprit.
A more professional approach involves using a motor tester or an OBD-II scanner. If you connect the adapter to the diagnostic connector, you can count the error codes. P0300 (accidental ignition failures) or P0301-P0304The last digit will indicate the number of the cylinder that is not working, which will significantly reduce the time for finding a fault.
Notice how the car behaves under load. If the tremors only occur when accelerating, the problem may be in the power system or low compression. If the engine is moving both on idles and under load, it is likely to be the electrician or candles.
⚠️ Attention: Be careful when conducting a test by turning off the components. High voltage in the ignition system can be dangerous. Do not touch the metal parts of the engine with your hands without dielectric gloves.
Failures of the ignition system: candles and coils
The most common cause of trimming on the Niva Chevrolet is the elements of the ignition system. Ignition candles are consumables, and their condition directly affects the quality of spark formation. The sugar on the electrodes, increased gap or failure of the insulator lead to the fact that the spark is either too weak or absent.
Owners of the Niv often face the problem of failure of the ignition module or individual coils (depending on the year of release). If there is no spark on the candle, but it is working, check the high-voltage wires (if you have them) for breakdown. In wet weather, the breakdown of the wires can be seen visually in the dark by the blue glow.
- 🔌 Ignition plugs: Check the gap (should be 0.7-0.8 mm) and the color of the lobster. Black lobster indicates a rich mixture, white indicates poor or overheating.
- ⚡ Coils and module: Call the primary and secondary windings with a multimeter, and the resistance must match the factory parameters.
- 🔌 High-voltage wires: Measure the resistance, it should not exceed 20 kOhms per meter of length. Check the integrity of the insulation.
It's often the case that replacing candles is only temporary, which means that the problem is deeper. injector It can pour gasoline by filling a new candle in a few minutes, so always do a comprehensive check.
☑️ Checking of the ignition system
Problems with the fuel system and nozzles
If the spark is all right, attention turns to fuel. Niva's Chevrolet injector engine is sensitive to gasoline quality. Bad fuel quickly disables the fuel filter and contaminates the nozzles. A clogged nozzle doesn't spray gasoline, it pours it in a jet, which prevents the mixture from ignition normally.
If it does not create enough pressure in the ramp (the norm for the Niva is about 4 atmospheres at idle and at least 3.2 under load), the engine will experience fuel starvation. Pressure can be checked by connecting a pressure gauge to the fuel ramp connection.
Pay special attention to the fuel pressure regulator. If the valve does not hold it, the pressure in the ramp drops immediately after the engine stops, which makes it difficult to start the next start and can cause tripling in the first minutes of operation.
| Element | Symptom of malfunction | Method of verification |
|---|---|---|
| Fuel injector | Tronia, black stain on a candle | Resistance measurement, torch check sprayed |
| Fuel pump | Power drop, tank noise | Pressure measurement in the ramp with a manometer |
| Fine cleaning filter | Failures during acceleration, tripling under load | Visual examination, replacement |
| Pressure regulator | Difficult launch, unstable XXX | Pressure check with vacuum tube removed |
How to clean the nozzles without removing?
There is a method of washing the nozzles without dismantling, and to do this, a special unit with a solvent is connected to the fuel ramp, turning off the regular gas pump, the engine runs on a cleaning liquid for about 20-30 minutes, but when there is a lot of contamination or valve coking, this method may not help, and sometimes even aggravate the situation by tearing off large dirt.
Air suction and engine sensors
The internal combustion engine runs on a mixture of air and fuel. If the proportions are broken, you don't expect stable operation. A common problem with Niva Chevrolet is the sucking of unaccounted air. It can get through cracks in the pipes, the gasket of the receiver or the sealing rings of the nozzles. The mixture becomes too poor and the cylinder stops working.
A key role in mixing plays Mass Airflow Sensor (MAAC)If it's contaminated or malfunctioning, the ECU gets the wrong amount of air incoming and makes the wrong mixture. You can check for DMRV by flipping the chip off it, and if the engine's performance has improved or hasn't changed, the sensor is probably dead.
It is also worth checking the throttle position sensor (DPD), incorrect readings of the angle of opening of the valve lead to jerks and tremors, especially when pressing the gas pedal, the normal voltage on the signal wire when the valve is closed is about 0.5-0.7 V.
Use a carburetor cleaner to find the air sucker. Sprinkle some fluid on suspicious joints of the pipes when the engine is running. If the speed changes, you've found the sucker. Be careful with the fire!
Mechanical causes of engine trimming
If the electrics and the fuel are fine, you have to look inside the engine. Mechanical problems are the most unpleasant and expensive. Low compression in the cylinder indicates that the gases are not compressed properly. The reasons may be different: a burn of the valve, a piston rings or a breakdown of the gasket.
Compression measurement is a mandatory procedure for the old engine. Normal value for the VAZ-2123 engine is 11-13 bar. The scatter between the cylinders should not exceed 1 bar. If the compression in one cylinder is much lower, pour 5-10 ml of engine oil and repeat the measurement. If the compression has increased - a problem in the rings, if it remains low - the charring of the valve.
Another hidden cause is a problem with the gas distribution mechanism, which is that a stretched HRM circuit or a downed valve timing phase causes the valves to open and close out of sync with the pistons, which causes unstable operation in all modes.
⚠️ Warning: The operation of an engine with a burnt valve or a broken gasket is strictly prohibited. This will lead to overheating, the destruction of the piston and the need for major repairs of the engine.
Mechanical faults are often disguised as ignition problems. Always start a deep diagnosis with a compression measurement to rule out a dead cylinder.
Software failures and Electronic Control Unit
The car's brains can't be discounted either. The electronic control unit (ECU) can mismanage the nozzles because of software errors or damage to the board itself. Sometimes the reason lies in oxidized contacts of the wiring connectors, especially in the engine compartment, where there is a lot of moisture and dirt.
It's worth checking the engine mass. Bad contact of a sub-conductor with a body or engine causes chaotic power surges, causing all sensors and coils to malfunction, and cleaning contacts often works wonders.
In rare cases, the flashing of the ECU to a newer version of calibrations helps if the manufacturer has issued updates to eliminate "childhood diseases" of the engine control system of a particular series.
Frequently Asked Questions (FAQ)
Why does Niva Chevrolet only touch the cold?
Cold friction is often due to the fact that one of the cylinders has a slightly lower compression or candles have an increased gap. At low temperatures, the mixture evaporates worse, and a weak spark can not set it on fire.
Can I drive if the engine is running?
You can get to the service, but it's neat, and a long trip will flush the oil off the cylinder walls with gasoline, get bogged down in the cylinder, and the catalyst will fail, and you'll better fix the problem right away.
Which candles are better to put on the Niva Chevrolet?
The plant recommends candles A17DVRM or their analogues (NGK, Denso, Bosch) with a potassium number of 17 and a thread of 14 mm. It is important that the gap is properly exposed, and the electrode material meets the operating conditions.
How often should the fuel filter be changed?
Given the quality of fuel in the regions, the fuel filter on the Niva Chevrolet is recommended to be changed every 15-20 thousand kilometers. Clogged filter is a common cause of power loss and tremor under load.