Ignition coil repair kits

SENTECH coil repair kits carry the coil reference number with the suffix N, e.g. SC7004N for coil SC7004. They allow damaged or worn coil insulators and high-voltage contacts to be replaced cheaply. The most common cause of coil failure is a dirty or damaged low-voltage connector; internal winding damage is the rarest.

Ignition coil repair kits – available exclusively from SENTECH.

You can view the kits in our online catalogue – enter the repair kit number in the search box to see what it looks like. Repair kit reference numbers are marked with the letter N.

Example: ignition coil SC7004 has the matching repair kit SC7004N.

Benefits of coil repair kits

  • low cost of repairing damaged or worn coil parts
  • low cost of reconditioning ignition coils
  • easy replacement of damaged coil insulators

How to use a coil repair kit

  1. Make sure the repair kit is the correct one for the type and model of your coil.
  2. Check the data in the catalogue and compare the parts in the kit with those fitted to the coil.
  3. Remove the old parts from the coil.
  4. Inspect the high-voltage contacts and assess their condition. Clean them with a suitable contact cleaner or, if necessary, rub them down with fine-grit abrasive paper.
  5. Make sure the spring contact elements in the kit will provide a proper electrical connection. The high-voltage contacts must touch each other so that the spark does not jump across the joint and burn it out.
  6. Make sure all parts are clean and dry. If necessary, clean any dirty parts, especially around the coil connector.
  7. Fit the repair kit parts to the coil and check that they are correctly positioned and seated.

The most common causes of ignition coil failure

  • damage around the low-voltage connector
  • damage to the high-voltage connector
  • internal coil damage

SENTECH ignition coil repair kit: coil boots, springs and insulators

Starting with the last item – internal damage – it has to be said that this is the rarest cause of coil failure. The coil winding itself very rarely fails. Soldered or mechanical joints inside the coil are more likely to be damaged, but since all the internal components are potted in resin, the internal connections are well protected.

The most common reason a coil stops working properly is a damaged or dirty low-voltage connector. Vibration, heat, temperature cycling and dirt cause the relatively small contacts between the coil and the wiring harness connector (which supplies power and the control signal) first to become dirty and tarnished, and later often to suffer mechanical damage. Unfortunately, if cleaning or repairing these parts does not help, the whole coil or the connector usually has to be replaced. Even so, do not rush into replacing the coil – first make every effort to repair the low-voltage connector.

While carrying out the repair, it is also worth inspecting the high-voltage connector and its insulator. This brings us to high-voltage connector damage. The flow of high-voltage current can leave a non-conductive deposit on the coil terminal. In addition, vibration and heat cause corrosion where the contacts meet, which sharply increases resistance and can eventually stop the spark from jumping at the spark plug.

Another factor that harms the coil's high-voltage connection is temperature change: the engine heats up while running and cools down when the vehicle is parked. The metal parts repeatedly expand and contract and, over time, lose good electrical contact.

For all these reasons it is worth repairing or servicing the ignition coil. Not every coil design allows the connector parts and high-voltage insulator to be replaced, but wherever it is possible, it is worth doing from time to time. As with ignition leads, these parts should be replaced after about 2–3 years of use.