Ignition & Electrical

Is your engine misfiring under full load, is the starter hesitating on a cold morning, or is the engine management not getting reliable signals from the sensors? This category brings together ignition, sensors, wiring harnesses, charging systems, starters, batteries, ECUs and horns for street and track cars. You will find parts for repairs as well as for your next project.

Spark plugs and plug wires for higher cylinder pressure

The ignition has to deliver a strong spark at the right moment, even when boost or compression is increased. Higher cylinder pressure typically makes it harder for the spark to jump the gap. That is why a tuned engine can require a colder spark plug and a smaller electrode gap. It depends on the engine, so follow the engine builder's or manufacturer's recommendation. Under spark plugs and glow plugs you will find brands such as NGK. Under spark plug wires and accessories you will find, for example, Kooks 10mm spark plug wire sets in several colours and wire separators that keep the wires apart and in place.

Sensors, wiring harnesses and electronic modules

The engine management can only calculate accurately when the signals are correct. Sensors such as the Edelbrock Air Charge Temperature Sensor measure the intake air temperature. A knock sensor detects knock so the management can retard the ignition timing. Wiring harnesses and relays are just as important, for example the Edelbrock Knock Sensor Harness #36125 and the EDL Pro-Flo EFI Fuel Pump Relay #3586. For electronic modules under ECUs, chips and programmers, check the connectors and the method of control. The Banks Power Pedal Monster Kit, for example, is available with either Molex MX64 or Aptiv GT 150 connectors and for use with a phone or the iDash 1.8.

How to choose parts for power and starting

• Power demand: Electric fuel pumps, fans and accessories put a load on the charging system. Check that the alternator can keep up with the consumption.
• Starter: Higher compression can require more cranking torque. Check the mounting, tooth count and clearance around the exhaust manifold or headers.
• Battery: Capacity, cranking current, dimensions and location determine the choice. Under batteries and battery management you will find, for example, CTEK 12V battery chargers such as the US 0.8 and MXS 5.0 Polar.
• Wiring and fuses: Use a wire gauge and fuses that match the load. Route the wiring away from heat and moving parts.

Other brands in the category include Granatelli Motor Sports, Arrowhead, Moroso and NAMZ. Always check the specifications, connectors and fitment for the specific part number.

Frequently asked questions

Should I switch to a colder spark plug after tuning?

It depends on how much cylinder pressure and heat the engine sees. More boost or compression can require a colder spark plug and a smaller electrode gap. Follow the engine builder's or manufacturer's recommendation, and check the spark plugs after the first few drives.

When should the spark plug wires be replaced?

Cracked, hard or discoloured wires and boots can indicate wear. The same goes for misfires in damp weather and sparks jumping to ground. Preferably replace the whole set, and use separators so the wires do not lie against each other.

Can a battery charger keep the battery charged over the winter?

A maintenance charger such as the CTEK MXS 5.0 Polar can keep a 12V battery charged while the car is parked. Check that the charger suits your battery, and follow the manufacturer's instructions for connection.

Can the car pass inspection with a new horn or extra electronics?

It depends on the product and the car. A horn typically has to be approved for road use, and changes to the engine management can affect inspection and insurance. Check the approval, such as E-mark, for the specific part number before installation.