Nissens has added ignition coils to its portfolio. Here, the company goes into detail about some common issues this essential part faces.
The typical ignition coil consists of a primary winding, secondary winding, iron core and housing, and is enclosed in a durable, heat resistant casing filled with epoxy for insulation.
The primary winding receives low voltage current from the battery, which builds a magnetic field around the iron core. When the current is interrupted, the collapsing magnetic field induces a high voltage surge in the secondary winding. This high voltage is then sent to the spark plug to ignite the air/fuel mixture in the combustion chamber.
Most contemporary engines utilise a coilon- plug (COP) design where the spark plug has its own coil mounted directly on its top, eliminating the need for spark plug wires and improving ignition precision. The pencil coil is a slim, elongated version of COP designed to fit deep into narrow spark plug wells, commonly used in compact engine layouts, and the rail coil design is a single unit with multiple coils mounted together, supplying several spark plugs from a centralised location.
Common symptoms of failure
The ignition system and coil issues directly affect the engine’s operation. Besides noticeably affecting the overall drivability, ignition coil failures can ultimately result in severe damage to the engine. Recognising the symptoms of a coil problem early is key to preventing these issues. A faulty or nonperforming ignition coil is generally easy to recognise from a range of symptoms:
Check engine light (CEL): Often the first indicator. Diagnostic trouble codes such as P030X (misfire) or P035X (coil circuit fault) point to specific cylinders or coils.
Hard starting or no start: A weak or failed coil can cause extended cranking or prevent the engine from starting, especially in cold conditions.
Engine misfires and rough idle: Misfiring cylinders result in rough idling, shuddering and poor acceleration.
Backfiring: Unburned fuel igniting in the exhaust system produces loud pops and can damage the catalytic converter.
Engine stalling: Intermittent coil failure may cause the engine to stall unexpectedly, posing safety risks.
Loss of power and poor fuel economy: Inefficient combustion due to weak spark leads to reduced power output and increased fuel consumption.
Common causes
Ignition coils are subject to various stress factors that can lead to failure. Understanding these helps in accurate diagnosis and prevention:
Internal coil damage: Open or shorted windings disrupt the coil’s ability to generate a spark. Overheating and age are common contributors.
Insulation breakdown and arcing: Cracks in the coil’s resin casing or carbon tracking allow voltage to escape, causing misfires and visible sparks.
Connector and wiring issues: Loose, corroded, or damaged connectors can mimic coil failure by interrupting power or signal flow.
Multiple coil failures: Often linked to underlying issues such as excessive spark plug gaps, lean fuel mixtures, or faulty ECU drivers. These conditions overstrain coils and lead to repeated failures.
Internal structural failures
Physical or electrical faults within the coil’s components:
Internal short circuit: Current bypasses windings, weakening spark output; caused by insulation breakdown or overheating.
Open circuit in windings: Broken wire prevents voltage generation, resulting in no spark and misfire or no start.
Carbon tracking or arcing: Spark diverts from plug path due to surface burns or cracks; often triggered by moisture or contamination.
Cracked housing or boot: Allows voltage leakage or environmental intrusion, leading to misfires and coil degradation.
Epoxy insulation failure: Breakdown of internal insulation material causes overheating and electrical instability.
Connector damage or corrosion: Interrupts electrical contact, causing intermittent coil operation or complete failure.
Review of incorrect performance parameters
Functional deviations of the coil:
Incorrect coil impedance: Disrupts voltage buildup, causing weak spark and misfires; often due to winding damage.
Incorrect charge current: Insufficient magnetic field buildup leads to low spark energy and poor combustion.
Incorrect discharge timing: Spark occurs too early or late, causing misfires, knocking, or rough running.
Voltage leakage: High voltage output escapes before reaching the plug, reducing spark strength and efficiency.
Overheating under load: Coil fails to maintain output during high demand, leading to misfires or stalling.
Inconsistent dwell time: Coil charging duration varies due to ECU or driver faults, affecting spark reliability.
Diagnostic methods and tips
Effective diagnosis of ignition coil issues involves a combination of visual inspection, electronic testing and practical techniques:
OBD-II scan: Retrieve misfire (P030X) and coil circuit (P035X) codes to identify affected cylinders.
Visual inspection: Check for cracks, carbon tracking, oil contamination and connector corrosion.
Spark test: Use an inline spark tester to verify spark strength and consistency.
Coil swap test: Move suspect coil to another cylinder and observe if the misfire follows.
Resistance measurement: Use a multimeter to check coil windings against the manufacturer’s specifications.
Replace all coils if one fails: In high mileage engines, a single coil failure often signals that others are nearing the end of their life. Replacing all the coils ensures balanced performance and avoids repeated labour costs.
New coil range
Nissens ignition coils are purpose built to meet the demands of modern engine systems and the aftermarket’s need for durable, high performance ignition system components. Developed through rigorous engineering and validated in advanced, among others, European manufacturing facilities, Nissens coils incorporate a series of targeted design enhancements that directly address the known failure modes of original equipment (OE) and other aftermarket coils.
Engineered for right first-time repairs and manufactured to the highest Genuine Nissens Quality standards, Nissens ignition coils are produced in-house, generally in an ISO and IATF 16949-certified European plant. They are thoroughly constructed using the latest technology, premium grade raw materials and proven engineering, and cover various design types from standard to pencil, COP, rail and block.
The initial Nissens ignition coil range caters for more than 230 models, covering in excess of 1,000 OE references across passenger car and light commercial vehicle applications, and offers 65 per cent plus coverage of the European car parc.
