The ignition system is one of the most critical components in your engine. Nissan Almera N16, especially when we are talking about a reliable but attention-demanding engine of the series QG15DE or QG18DE. Precisely from serviceability ignition coils depends on the stability of the power unit, fuel efficiency and the absence of failures during acceleration. Many owners are faced with a situation where the car starts to stall, but the diagnostics show errors in the spark plugs, although the root of the problem lies in the module under the hood.
Ignoring the symptoms of a coil malfunction can lead to failure electronic control unit (ECU) or a catalytic converter, the repair of which will cost tens of times more than replacing the coil itself. In this article we will look at how to carry out diagnostics yourself using a minimal set of tools, and what to do if the check reveals problems.
Signs of a malfunctioning ignition coil on Almera N16
The first signal of problems with the ignition system is often unstable engine operation at idle speed. You may notice that the tachometer needle begins to float, and the engine itself vibrates more than usual. In some cases, this is accompanied by a characteristic clicking sound made by an unresponsive cylinder.
When you try to move away or when you press the gas pedal sharply, the car may jerk, lose power, or even stall. These symptoms are especially pronounced in damp weather or after washing the engine, when moisture gets on high-voltage wires and creates current leaks.
- π₯ The engine runs unevenly and stalls even on a warm engine
- β½ Significant increase in fuel consumption for no apparent reason
- π‘ The Check Engine light on the dashboard came on
- π Difficulty starting the engine, especially in the cold season
If you notice at least one of the listed signs, you need to have it checked as soon as possible. A delay in diagnosis can result in the faulty coil starting to connect to ground, damaging the wiring or the engine control unit itself.
Necessary tools and preparation for diagnosis
To properly check the ignition coil, you do not need sophisticated equipment, but a basic set of tools is required. You will need a multimeter that can measure resistance between 20k and 200 ohms. Also have a set of screwdrivers and wrenches ready, as access to the coils may be limited by other engine components.
It is important to ensure that the engine is completely cool before starting work. Ignition coils are attached directly to the spark plugs, and working in a hot engine compartment can lead to burns or deformation of the plastic elements. Disconnect the negative battery terminal to eliminate the risk of a short circuit when disconnecting the connectors.
βοΈ Preparation for diagnosis
In some cases, it may be necessary to visually inspect high-voltage wires if they are removable, or check the integrity of the module housing. If you have a model with individual coils (coil-on-plug), then the test will be slightly different from diagnosing older systems with one common coil.
β οΈ Warning: Never disconnect high voltage wires or connectors from the ignition coil while the engine is running. This may result in electric shock or damage to the ECU due to power surges.
Visual inspection and checking contacts
The first step in diagnosis is always a thorough visual examination. Remove the plastic engine cover, if installed, and carefully inspect all ignition coils. Look for signs of breakdown, dark streaks on the body, melted plastic or traces of oil inside the spark plug wells.
Oil in the spark plug well is a common problem on Nissan Almera N16, which leads to rapid failure of the coils. Rubber seals harden over time and no longer protect the reel from engine oil. If you see oil, replacing the coil may not help unless the cause of the valve cover leak is addressed.
Check the condition of the electrical connector connected to the coil. The contacts inside must be clean, without oxidation, carbon deposits or traces of melted plastic. Often the problem lies in poor contact, and not in the coil itself.
- π Inspect the case for cracks and signs of breakdown
- π§ Check for oil in the spark plug wells
- π Assess the condition of the power connector contacts
- π‘οΈ Make sure there are no signs of overheating of the plastic
If there is no visual damage, proceed to an instrumental check. Visual inspection can screen out obvious faults, but cannot detect internal winding breaks or changes in resistance, which require precise measurements.
What to do if the coil is filled with oil?
If the reel is filled with oil, it must be thoroughly washed and dried. However, even after drying, oil may remain inside the windings and cause breakdown in the future. The best solution is to replace the coil and at the same time replace the valve cover seals or valve cover gasket to eliminate the source of the leak.
How to check coil resistance with a multimeter
This is the most reliable way to determine the serviceability of the coil without removing it from the car. You need to measure the resistance of the primary and secondary windings. To do this, switch the multimeter to resistance measurement mode (Ohms).
First check the primary winding. Touch the multimeter probes to the low voltage contacts on the coil connector. Normal resistance for most coils QG motors ranges from 0.5 to 2.0 Ohm. If the device shows infinity (open) or zero (short circuit), the coil is faulty.
Then check the secondary winding. Apply one probe to the high voltage contact (central terminal), and the second to the ground contact (usually a housing or a special terminal terminal). The value should be in the range from 5 to 15 kOhm.
β οΈ Attention: When measuring the resistance of the secondary winding, be sure to remove the coil from the spark plug or disconnect the high-voltage wire to avoid inflated readings due to spark plug resistance.
If the readings fall outside the specified limits, this is a sure sign that the coil requires replacement. However, remember that even within normal limits, the coil may operate unstably at high loads due to inter-turn short circuit, which is not always visible on a cold multimeter.
| Winding type | Measuring points | Normal value | Symptom of malfunction |
|---|---|---|---|
| Primary | Low voltage contacts | 0.5 - 2.0 Ohm | Infinity or 0 Ohm |
| Secondary | Center pin and ground | 5000 - 15000 Ohm | Value above 20 kOhm or below 3 kOhm |
| Housing | Contact and coil body | Infinity | Any final value |
- Cheap Chinese tester
- Mid-range digital multimeter
- Professional scanner
- Analog device
Diagnostics by replacement and substitution
If you have access to a known-good coil or want to save time on measurements, use the substitution method. This is especially true if you have a specific cylinder and you want to pinpoint the problem.
Remove the coil from the problem cylinder and install in its place a coil from another, properly working cylinder. Start the engine and listen to its operation. If the βtripleβ has moved to another cylinder, then the coil is to blame. If the problem remains in the same place, then the problem is in the spark plug, wiring or the cylinder itself.
This method eliminates false diagnoses associated with poor contacts in the connector or problems with wiring to the coil. It also helps test the coil's performance under load, something a multimeter cannot do.
- π Swap the coils of adjacent cylinders
- π Start the engine and evaluate the nature of the vibrations
- π Track if the misfire cylinder has changed
- π οΈ Check the condition of the spark plug after replacing the coil
If after replacing the coil the engine runs smoothly and there are no more errors on the scanner for a specific cylinder, you have successfully found the cause. This is the fastest way for beginners who don't want to deal with numbers on a multimeter.
The substitution method is the most reliable way to test a coil βin the field,β as it allows you to see the engineβs reaction to replacing the unit in real time.
Specifics of replacing the coil on Nissan Almera N16
Replacing the coil with Nissan Almera N16 Itβs not particularly difficult, but it does require some care. On motors QG18DE coils often stick to spark plug wells due to oil and high temperatures. Do not try to pull it out with a jerk, as you may break the plastic housing or damage the spark plug insulator.
Before installing a new coil, be sure to clean the spark plug well of dirt and oil. Use compressed air or a rag to prevent debris from entering the combustion chamber when starting the engine. Also lubricate the rubber seal of the new reel with a small amount of silicone grease for easy installation.
β οΈ Attention: When installing a new coil, do not apply excessive force to the plastic housing. Make sure that it is completely seated, otherwise the contact will be broken and the problem will return.
After installing the coil, connect the power connector and make sure that it clicks into place. Check the fixation of the fastening bolts, if they are provided for in the design of your model. On some modifications, the coil is held in place only by pressing against the spark plug, but the presence of fasteners increases reliability.
Common diagnostic mistakes and how to avoid them
One of the most common mistakes is replacing the coil without checking the spark plug. Often a worn or sooty spark plug creates increased resistance, which leads to failure of the new coil. Always change the spark plugs along with the coils, or at least inspect them carefully.
Another mistake is ignoring the condition of high-voltage wires (if your configuration has them). The wires may have microcracks that allow current to flow to ground, creating a false impression that the coil is faulty. Checking the wires should be a mandatory step.
Also, many people forget to check the integrity of the ignition system fuse. If the fuse is blown, the coil will not receive power, and diagnostics with a multimeter will show an open circuit, although the coil itself may be fine.
Before purchasing a new reel, check the part number on the old part. On the Almera N16 there were several modifications of coils that were not interchangeable in terms of electrical characteristics.
FAQ: Frequently asked questions
How many ignition coils are installed on the Nissan Almera N16?
Depending on the engine type, on Nissan Almera N16 either one common coil is installed (on older versions), or four individual coils (coil-on-plug) on series motors QG. The most common system is one with four separate coils.
Is it possible to drive with a faulty ignition coil?
Technically the car can move, but this is highly discouraged. Operation of the engine with misfires leads to unburnt fuel entering the catalyst, which causes its overheating and destruction. This also increases the load on the starter and generator.
Which reel is better: original or analogue?
Original coils Nissan (often made by Denso or Hitachi) are considered the most reliable and durable. High-quality analogues from brands like NGK or Bosch are also acceptable, but cheap Chinese knockoffs often fail after a few months.
Why does the new coil burn out again?
This may be due to wiring problems, a short to ground, a faulty ECU, or the installation of poor-quality spark plugs. It could also be caused by oil getting into the spark plug well.
Do I need to reset errors after replacing the coil?
After replacing the faulty part and eliminating the causes of the breakdown, errors in the ECU memory may remain. It is recommended to reset them using a diagnostic scanner or by disconnecting the battery terminal for 10-15 minutes to allow the system to recheck the parameters.