Fig. 9.7. Location of the temporary ignition timing change connector for adjusting the octane number of the fuel
If, due to necessity or carelessness, you have filled the fuel tank with the wrong fuel (the recommended fuel for your car is Euro Super with an octane rating of 95), detonation knocks will appear under the hood of your car no more than 2 km after refueling. Stop the car immediately to adjust the ignition timing. The Fiesta has an octane service connector for this purpose, located on the left side wall in the engine compartment (Fig. 9.7). Squeeze the clamp and disconnect the connector. After this intervention, the engine power will decrease slightly, but this will not lead to any negative consequences. After the next refueling with the recommended fuel, do not forget to connect the service connector.
PRACTICAL ADVICE
The spark plug won't come out
If excessive force is required to remove the spark plug, do not remove it as this may damage the threads in the cylinder head.
In this case, warm up the engine and try to remove the spark plug.
Warning.
A hot engine can burn your hands. So wait until the engine cools down. This advice also has a technical basis: cold spark plugs screwed into a hot cylinder head will sit as if welded. To make it easier to screw in and out the spark plug, apply a thin layer of graphite from a soft pencil or a copper-based plastic lubricant to its threads. If you use motor oil, the spark plug will burn to the cylinder head and it will be impossible to unscrew it.