NC MX5 Engine Misfire

Tips and Tricks -

NC MX5 Engine Misfire

The early model NC’s (2005-2006) can suffer from an engine misfire caused by damaged wiring to the coils. This is usually first noticed as an intermittent engine misfire that develops into a full misfire in time. Another symptom can be “popping” from the exhaust on overrun.

Easiest way to check is lift the engine cover which just clips down
The top of the engine is revealed and shows the 4 engine coils
With the engine running gently wriggle the wiring around the plug. If the engine stumbles or misfires you have weakened/broken wires
With the engine running gently wriggle the wiring around the plug. If the engine stumbles or misfires you have weakened/broken wires

We carry a spare plug all set up and ready to go in the event of a failure. As you can see 2 of the wires are a much thicker gauge than the last one. The last one (coloured) is always the one that breaks and the break is just as the wire exits the grey plug.

The insulation is never broken so a visual inspection will not show anything.

The main cause of this is the wiring is unsupported and the weight of the harness over time causes the wiring to fail.