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Most likely causes for ignition failure

By autotech-nath on November 1, 2017

Ignition is an integral element in the start-up of an engine and Hella’s ignition range continuously expands to ensure the best possible vehicle coverage. The ignition specialist is also committed to supporting technicians concerning these increasingly complex systems, to understand the most probable causes for failure, through its dedicated technical team and free online portal, Tech World.

A failure can manifest itself through various symptoms, including the engine not starting, engine misfiring, poor acceleration, loss of power, the ECU switching to ‘limp-home’ mode, engine warning lamp illuminated or an error code being stored. If any of these symptoms appear, the most likely reason is the ignition system, which must be checked and the required replacement components installed.

Hella has identified the four most common failures and the causes behind them. Internal short circuits can be instigated by an aging, overheating ignition coil, a faulty ignition module or a defective output stage in the control unit. These symptoms can be rectified by simply replacing the damaged components.

Another common issue is an error in the control voltage, which results in the coil charging time being increased as the voltage supply is too low, triggered by faulty wiring or a weak battery. This can lead to premature wear or overload on the ignition control unit or the output stages in the ECU.

Physical damage to the ignition cable insulation, caused by oil leaks, abrasion or abuse, results in sparkover, erratic running and premature wear. Technicians must check the cables and replace them if any damage is seen.

Finally, contact resistance in the wiring, due to humidity/ water ingress penetrating the ignition coil, is frequently caused by something as simple as engine washing and the use of grit in winter. This is something that technicians should be aware of and check first.

Hella’s ignition programme is regularly updated and currently covers more than 100 references, with a high percentage being OE on popular European and Japanese models.

Phone: 01295 662 400



About Autotechnician
Autotechnician is a magazine published nine times a year, delivering essential information to independent garage owners and technicians in the UK. Delivered both digitally and in print, autotechnician provides readers with technical, training, business advice, product and news, allowing our readers to keep up to date with information they need to run and work within a modern workshop.
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