The situation when Daewoo Gentra or Chevrolet Lacetti Bad start on the cold, familiar to many owners of these popular sedans and hatchbacks. The engine can be a long starter, grab and stall or not respond to the turn of the key, especially in winter. This behavior of the car is not only annoying, making you late for work, but also signals serious failures in the operation of the life support systems of the engine.
Reasons why Lacetti badly started, there can be many: from a banal discharged battery to a complex malfunction in the electronic control unit. Most often, the problem lies in the violation of mixture formation or failures in the ignition system, which on the warmed engine do not appear so clearly. Owners should pay attention to the nature of the engine in the first seconds after start-up.
In this article, we will analyze in detail the main nodes that require verification, and compile an algorithm of actions for diagnosis. Ignoring the symptoms can lead to the fact that the car will stop starting at the most inopportune moment, and repairs will cost much more than planned prevention.
Problems with the idling regulator (RX)
One of the most common reasons why Lacetti or Gentra poorly started on cold, there is pollution or malfunction of the idle regulator. This unit is responsible for the supply of air bypassing the closed throttle, ensuring stable operation of the engine at low revs. If the RX channel is filled with soot or the valve itself is jammed, the engine does not receive the right amount of air to start.
Symptoms often manifest as floating turns immediately after starting or the need to constantly gasse to prevent the machine from stalling. On a cold motor, the gap in the valve can be critically small due to temperature expansions or dirt. Owners often note that after warming up the problem goes away, as the thermal expansion of the metal or liquefaction of sediments temporarily restore the permeability.
For diagnosis, it is necessary to remove the throttle node and visually assess the condition of the RX channel. Often, oily soda accumulates inside, which is mixed with dust from the air filter.
- 🔧 Remove the regulator and check the stock for free running and no snacks.
- 🧼 Wash the channel and the valve itself with a special carburetor cleaner to pure metal.
- ⚙️ Check the integrity of the sealing ring, which often tans in the cold and lets in excess air.
⚠️ Note: When installing the regulator in place, make sure that the distance from the tip of the needle to the mounting flange is strictly 23 mm. If the needle is pushed too strongly, during installation, you can damage the mechanism, and then Lacetti It will stop starting completely.
After cleaning and assembly, a procedure for adapting the throttle valve is often required, although on many cars of this generation it passes automatically after several cycles of ignition. If the cleaning did not help, the stepper motor of the regulator itself may have failed, and it will have to be replaced.
Failures in the ignition and candle system
The second most important cause of unstable start is the ignition system. On engines of 1.4 and 1.6 liters, which are most often found on the Chevrolet LacettiIndividual ignition coils are used. Over time, the insulation of the coils cracks, especially in conditions of temperature changes, which leads to breakdowns in the mass, which are especially noticeable in wet and cold weather.
The ignition plugs also play a critical role. If the gap between the electrodes is increased or the candles are formed by a stain, the spark becomes weak and cannot ignite the cold, rich mixture. Visual inspection of candles can tell about the state of the engine: black nagar indicates a rich mixture, white - about poor or overheating, and oil plaque indicates problems with piston rings or oil caps.
Checking high-voltage wires (if any in your modification) or coil tips requires care. In the dark, you can see the spark in the hood space, giving out the places of current leakage.
- 🕯️ Unscrew the candles and assess the color of the lobe and the condition of the central electrode.
- ⚡ Check the coils for cracks and breakout marks, replacing the doubtful instances.
- 📏 Measure the resistance of the coils with a multimeter if there is a suspicion of their malfunction.
For Lacetti It is recommended to use candles with a potassium number strictly corresponding to the manufacturer's specification (usually 1.6 for atmospheric motors).
Temperature Sensors and Their Impact on Launch
Electronic control unit (ECU) of the engine Daewoo Gentra and Lacetti forms a fuel mixture for launch, based on the readings of the coolant temperature sensor (TTP). If the sensor transmits incorrect data, for example, telling the control unit that the engine is warm when in fact it is cold, the mixture will turn out too poor.
As a result, the engine will be a long starter spinning, trying to start on a mixture designed for a warmed-up state. Often a faulty sensor has variable resistance, which is why the arrow on the dashboard can behave adequately, and distorted signals leave the ECU, since different contacts or circuits are responsible for the readings.
Diagnosis of TTZ is made by measuring its resistance at different antifreeze temperatures and comparing the readings with the reference table. It is an inexpensive sensor and replacing it often solves the problem of a difficult start-up.
| Temperature (°C) | Resistance (Om) - Norma | Permissible range |
|---|---|---|
| 20 | 2500 | 2300 - 2700 |
| 40 | 1200 | 1100 - 1300 |
| 60 | 600 | 550 - 650 |
| 80 | 330 | 300 - 360 |
It is also worth checking the connector of the sensor for oxidation of contacts. In the under-hood space, moisture and reagents do their job by disrupting electrical contact. The oxides create additional resistance by distorting the signal that arrives at the EBOU.
Fuel system: pressure and injectors
If Lacetti Badly starts on the cold, the reason may lie in the loss of fuel pressure in the ramp. After the engine stops, the pressure in the system must be maintained for a long time due to a return valve located in the gas pump or fuel ramp. If the valve does not hold, the gasoline drains back into the tank and the pump takes time to re-inflate the main line.
A long scrolling starter in this case is just the time it takes to create working pressure. This can be checked by connecting the pressure gauge to the fuel ramp and tracking the pressure drop after the ignition is turned off. The norm is to maintain pressure for several hours.
In addition, nozzles may be contaminated or have leaky locking. If the nozzle "flows" after stopping, gasoline accumulates in the cylinder, washes the oil film and pours candles, which makes re-starting impossible without purging the cylinders.
- 🛢️ Check the pressure in the fuel ramp with a pressure gauge (normal about 3.8-4.0 bar).
- 🔍 Check the fuel filter that is used Lacetti It is often clogged with dirt for winter.
- 🚿 Consider ultrasonic cleaning of nozzles if the mileage is high.
⚠️ Warning: Before disconnecting the fuel line, be sure to relieve pressure in the system by removing the fuel pump fuse and letting the engine work until it stops. Otherwise, you can get a burn or fire due to the spraying of gasoline under pressure.
Fuel quality also plays a role. In winter, gasoline may contain water, which, when frozen, blocks the fuel system. The use of quality dehydrator additives can prevent this problem.
Compression and GRM status
On cars with a mileage of more than 150-200 thousand kilometers, mechanical wear of the engine cannot be excluded. If Chevrolet Lacetti Badly starts on cold, this may be a consequence of low compression in the cylinders. The cold motor has large thermal gaps, and if the piston rings are laid or worn, the pressure in the cylinders will not be enough to ignite the mixture.
Another critical issue for engines E-TEC II, installed on these models - stretching of the belt of the timing or wear gears. The gas distribution phases may be lost, which will lead to improper filling of the cylinders. In some cases, the belt can jump on the tooth, which will immediately affect the engine.
Checking compression is a mandatory stage of diagnosis if all previous methods have not yielded results. Measurement is carried out on a warm and cold engine to compare the results.
Normal compression for Lacetti 1.6: 11-13 bar
Spread between cylinders: not more than 1 bar
If the compression is low, you can try pouring some engine oil into the cylinders. If the compression increases after that, then the problem is in the rings. If it remains low - the problem is in the valves or gasket of the GBC.
☑️ Diagnostics of the mechanical part
The effect of the battery and starter
Often owners are looking for complex reasons in the engine, forgetting that for a confident start of a cold engine requires a high speed of rotation of the crankshaft. If battery Old or low capacity, it will not be able to spin the starter to the required turns, especially in winter when the oil is thick.
Starter on Daewoo Gentra and Lacetti It also has the property of wearing out. Wear brushes, bushings or closure of the windings lead to the fact that the starter twists slowly, "traction". Visually, this may look like normal work, but in fact, the rotation frequency is not enough to create the desired thinning and spark formation.
Check the battery terminals and the place of mass connection to the body and engine. Oxidated contacts create a huge resistance that “strangles” the starter, preventing it from developing full power.
- 🔋 Check the voltage at the terminals of the battery under load (when torsion by the starter it should not fall below 9.5-10 V).
- 🧹 Clean the terminals and mass contacts to a metallic sheen.
- 🔩 Evaluate the starter’s work: if it warms or sparkles, it requires a bulkhead.
In winter, the electrolyte density in the battery should be higher than in summer, so that the battery does not freeze and give full current. A weak charge is often the only reason why a car doesn't start in the cold.
Frequently Asked Questions (FAQ)
Why does Lacetti start and immediately stop on the cold?
Most often, this indicates a malfunction of the idling regulator (RXX) or the sucker of unaccounted air. Also, the cause may be a clogged fuel filter or a faulty throttle position sensor, which prevents the control unit from going into warm-up mode.
How often should I change the candles to Lacetti 1.6?
The life of spark plugs depends on their type and quality of fuel. Normal nickel candles are recommended to be changed every 20-30 thousand km, and iridium or platinum candles can walk up to 60 thousand km. However, in urban conditions and incomplete fuel, the interval is better to reduce to 30 thousand.
Can a lambda probe affect the start of a cold engine?
The oxygen sensor (lambda probe) begins to work only after warming up, so at the time of cold start it has practically no effect. However, if it is faulty and gives incorrect data immediately after start, the engine can quickly stall or run unstable in the first minutes.
What if the problem persists after the sensors are replaced?
If replacing sensors and cleaning nodes did not help, you need to conduct a computer diagnostics with real-time viewing of parameters. Perhaps the problem lies in the software failure of the ECU, requiring flashing, or in a hidden fault of the wiring, which is visible only on the oscilloscope.