HELLA explains importance of correct fault diagnosis

Although not seasonal products in themselves, other factors can contribute to ignition coil breakdown that are often due to the effect of worsening weather on associated components. In turn, this puts additional strain on the coil and causes it to fail. HELLA says it is the original equipment (OE) fitment for almost 130 million vehicles throughout Europe, so availability and quality are a given.

Even without any additional strain brought about by winter, ignition coils operate in a demanding working environment where they are subject to high electrical, mechanical, thermal and chemical stress, so they need to be manufactured to the strictest standards, using the highest quality materials to work perfectly and over a long period, the company said.

Insufficient output voltage or energy will cause misfiring and incomplete fuel combustion in the cylinder, which can increase the vehicle’s fuel consumption, exhaust emissions and potentially, damage its catalytic converter.

Therefore, if a problem arises, irrespective of the type of ignition coil – single, dual or four-spark or contact/transistor controlled – factors must remind their workshop customers that the correct fault diagnosis is critical and basic principles for the right procedure to assess them must be followed (right).

During all testing work on the ignition system, faults established during tests with the oscilloscope are not necessarily faults caused by the electronic system: they can also be caused by a mechanical problem in the engine; for example, this may be the case if compression in one cylinder is too low, which means the oscilloscope could show the ignition voltage for this cylinder to be lower than that of the other cylinders.

HELLA Electronics Product Manager, Matthew Smart, explained: “As vehicles continue to change, we work with vehicle manufacturers to develop the technology needed. Ignition and engine management is such a crucial element for the correct running of the engine, so to fully assist workshops we transfer this OE knowledge and technology to ensure that factors have access to the best offering for their customers.

“To ensure their customers can be served quickly and efficiently, we recommend factors keep the most popular references on their shelves; however, HELLA UK has a 90,000 sqft warehouse that allows us to stock a comprehensive range, which provides them with access to the parts they need when their customers need them.”

Visual inspection on the vehicle:

• Check the ignition coil for mechanical damage
• Check the housing for hairline cracks and sealant leaks
• Check the electrical wiring and plug connections for damage and oxidation

Check the electrics using a multimeter or oscilloscope:

• Check the voltage supply to the ignition coil
• Check the triggering signal from the ignition distributor, ignition control unit, or engine control unit

Testing with the diagnostic unit:

• Read out the fault memory of the ignition system or engine control
• Read out parameters