The situation when Nissan Almera G15 refuses to start in the morning, familiar to many owners of this model. The problem is especially acute in winter or after the car has been parked for a long time in the garage. The engine turns the starter, but does not catch, or operates unstable in the first minutes of warming up, which causes serious anxiety for the driver.
There can be many reasons for this behavior: from a banal discharged battery to serious malfunctions in the fuel supply system or engine control. Diagnostics in this case, it requires a systematic approach, since the symptoms are often similar for different breakdowns. Ignoring the problem can lead to complete failure of the unit at the most inopportune moment.
Ignition system and glow plugs
One of the most common reasons for difficulty starting a cold engine is the condition of the ignition system. Spark plugs lose their properties over time and the gap on them can increase, making it difficult to spark at low temperatures. If the spark is weak, the mixture in the cylinders simply does not ignite the first time.
Owners of gasoline versions should pay attention to the condition of the spark plugs themselves and high-voltage wires. Insulation failure wires often leads to current leakage, especially when moisture or condensation gets on them. In frosty weather, condensation inside the spark plug wells can become a conductor that knocks down the spark.
For diesel modifications, glow plugs are critical. If one or more of them fail, the compression in the cylinder may not be sufficient for the mixture to ignite spontaneously. Checking the resistance of the glow plugs is the first thing to do when diagnosing a diesel engine.
- 🔥 Check the condition of the spark plug electrodes: carbon deposits or oil deposits require replacement.
- ⚡ Measure the resistance of high-voltage wires; it should not exceed the manufacturer’s standard.
- ❄️ For a diesel engine, be sure to check the operation of the relay and the glow plugs themselves with a multimeter.
⚠️ Attention: If you notice that there is oil deposits on the spark plugs, this may indicate wear on the oil rings or valve guides. In this case, simply replacing the spark plugs will not solve the problem for long.
Problems with the fuel system and pressure
The fuel supply system plays a key role in starting the engine. If fuel pump does not create the necessary pressure in the ramp, the engine will spin for a long time with the starter until a sufficient amount of gasoline accumulates. Often the problem is the pump check valve, which does not hold pressure after the engine is stopped.
When starting from cold Nissan Almera requires a richer mixture. If the fuel pressure regulator is not working correctly, the mixture will be too lean to ignite. It is also worth checking the condition of the fuel filter, since its clogging limits the supply of gasoline at the time of peak loads at the start.
Additionally, you should pay attention to the injectors. If they leak or don't atomize fuel properly, the engine will run rough or won't start at all. Clogged injectors often cause misfires and floating speed on a warm engine, but they are especially noticeable during a cold start.
- 🛢️ Check the pressure retention in the fuel rail after turning off the ignition.
- 🚿 Clean or replace the injectors if they are not working properly.
- 🔧 Replace the fuel filter if the mileage exceeds the recommended interval.
- Weak spark
- No fuel pressure
- Problems with sensors
- Low battery
Sensors and electronic controls
The electronic control unit (ECU) makes decisions on the amount of fuel and spark generation time based on sensor readings. If crankshaft position sensor (DPKV) transmits incorrect signals, the computer simply will not be able to synchronize the operation of the engine. This is one of the most common reasons why a car does not start, although the starter turns vigorously.
The coolant temperature sensor (CTS) also plays an important role. If it shows that the engine is warm, but in fact it is cold, the ECU will not send a command to enrich the mixture. As a result, the engine will start with difficulty or stall immediately after starting. An error in the readings of this sensor often leads to excessive fuel consumption.
The absolute pressure sensor (MAP) and the mass air flow sensor (MAF) influence the calculation of the amount of air entering the cylinders. Contamination or malfunction of these elements disrupts the balance of the air-fuel mixture. In modern models Almera G15 Sensor errors are often accompanied by the Check Engine light coming on.
Sometimes the problem lies in the wiring or oxidation of the contacts. Vibration and temperature changes can degrade wire insulation, causing intermittent electronic malfunctions.
- 🔍 Run computer diagnostics to read errors and view sensor readings in real time.
- 🌡️ Check the resistance of the DTOZH and compare it with the table values for different temperatures.
- 🔌 Inspect the sensor connectors and contacts for oxidation or moisture.
How to check DPKV without a scanner?
Disconnect the sensor connector and measure the resistance between the contacts. The value should be in the range of 500-700 Ohms. Also check for metal shavings on the tip of the sensor, which may interfere with the signal reading.
Mechanical engine problems
If the electronics and fuel system are fine, the problem may be engine mechanics. Low compression in the cylinders does not allow creating sufficient pressure to ignite the mixture. This is especially true for cars with high mileage, where the wear of the piston group has already reached a critical point.
The breakthrough of gases through the piston rings or loose valves reduces compression. When cold, the gaps between parts are minimal, and even minor wear can prevent the engine from starting. Warming up the engine often temporarily improves the situation as the metal expands and seals the gaps.
It is also worth checking the condition of the timing belt. If it has jumped one or more teeth, the valve timing will be disrupted. In this case, the engine may be extremely unstable or may not start at all. On Nissan Almera this may occur due to wear on the tension roller or the belt itself.
Low compression is often accompanied by increased oil consumption and smoke from the exhaust pipe. If you notice these symptoms, you should not delay engine diagnostics, as this may lead to major repairs.
- 📉 Measure compression in all cylinders and compare the results with each other.
- ⏱️ Check the timing marks and the condition of the tension roller.
- 💨 Pay attention to the color of the exhaust gases and oil consumption.
☑️ Compression check
Electrics and battery
In winter, the load on the battery increases many times over. The engine oil thickens and the starter requires much more energy to crank the crankshaft. If battery even slightly discharged or with reduced capacity, it will not be able to provide enough current to start.
The starter can also be a source of problems. Wear of starter bushings or brushes leads to the fact that it does not develop the required speed. In cold weather this becomes critical as engine resistance increases. Sometimes the problem is solved by replacing the bushings or cleaning the manifold.
Poor connections at the battery terminals or engine ground can cause a voltage drop. Oxidation of the terminals creates additional resistance, and even a working battery will not deliver the required current. Always check the cleanliness and tightness of the contacts before diagnosing other systems.
Low voltage may cause the ECU to malfunction or shut off the fuel injectors for safety reasons.
- 🔋 Check the density of the electrolyte and the voltage at the battery terminals under load.
- 🔌 Clean the battery terminals and ground contacts from oxides and dirt.
- ⚙️ Check the operation of the starter: it should rotate the engine quickly and confidently.
Before the onset of frost, remove the battery and bring it into a warm room. This will significantly extend its service life and ensure reliable starting in any weather.
Crankcase ventilation system and EGR valve
A clogged crankcase ventilation system (CVS) can cause a vacuum to form in the engine, preventing fuel flow. If the positive crankcase ventilation (PCV) valve is stuck open, it can suck in excess air, leaving the mixture lean. This is especially noticeable during cold starts.
The Exhaust Gas Recirculation (EGR) valve can also cause problems. If it does not close tightly, exhaust gases enter the intake manifold when the engine is turned off. When trying to start, the mixture becomes too contaminated with exhaust gases, making it difficult to ignite.
On engines Nissan HR15DE and HR16DEinstalled on Almera G15, coking of the EGR valve is common due to the use of low-quality fuel. Regular cleaning of this unit helps maintain stable engine operation.
Ignoring problems with crankcase ventilation can lead to seal breakthroughs and oil leaks. Unvented crankcase pressure seeks out weak spots in the seals.
- 💨 Check the operation of the PCV valve for jamming and contamination.
- 🌫️ Clean the EGR valve from carbon deposits and check its tightness.
- 🔍 Inspect the ventilation system pipes for cracks and breaks.
The crankcase ventilation system and EGR valve are often overlooked in diagnostics, but their malfunction can be the main cause of unstable idle and difficult cold starting.
Comparison table of causes and symptoms
For ease of diagnosis, below is a table that will help compare symptoms with possible causes. This will allow you to narrow down the troubleshooting area and save time on a service visit.
| Cause | Cold symptom | Symptom when hot | Test method |
|---|---|---|---|
| Weak candles | Long scroll, troit | Can triple, failures | Visual inspection, spark test |
| Temperature sensor | Won't start, black smoke | Excessive fuel consumption | Reading data by scanner |
| Fuel pump | No pressure in the ramp | Power Loss | Pressure gauge on the fuel rail |
| DPKV | No spark, no fuel | Abrupt stop | Oscilloscope, multimeter |
| Compression | Won't start, hissing | Blue smoke, oil consumption | Compressometer |
If the engine does not start for more than 10 seconds in a row, be sure to take breaks so as not to overheat the starter and completely discharge the battery.
Regular maintenance is the key to ensuring that your car will start the first time in any frost. Don’t forget to change filters, spark plugs and check the condition of the sensors according to the manufacturer’s regulations. Ignoring minor problems often leads to major breakdowns, the repair of which will cost many times more.
Frequently asked questions (FAQ)
Why does the Nissan Almera G15 start, but immediately stall when cold?
This is often due to contamination of the throttle valve or a malfunction of the idle air control (IAC). The ECU cannot maintain speed when the throttle is open because it does not take into account the additional air. The throttle position sensor (TPS) may also be at fault.
Could the problem be with the fuel pump if it can be heard running?
Yes. The fuel pump may hum, but not create the necessary pressure due to wear or clogging of the receiver mesh. The problem may also be in the check valve, which does not maintain pressure in the system after shutdown.
How to check the coolant temperature sensor without a scanner?
It is necessary to measure the resistance of the sensor with a multimeter at different temperatures. Compare your values with the resistance chart for your vehicle. If the readings are very different, the sensor requires replacement.
Does fuel quality affect cold starting?
Definitely yes. Low octane fuel or fuel with a high water content may not ignite at low temperatures. Also, additives in low-quality gasoline can quickly coke the injectors.
What to do if the car starts only with a tow?
This indicates a serious problem with the ignition or compression system. If the car starts and runs normally from a tow, it is possible that the starter is not developing the required speed, or there is a problem with the fuel supply when the starter is cranked.