What does the spark plug face say? (Focus Turnier 1)

Spark plugs are, to some extent, the main witnesses of the combustion process. The appearance of the spark plug electrodes (the spark plug face) tells the technician whether the engine is running optimally. Therefore, when checking the removed spark plugs, pay attention to the following points.

The top of the insulator is light gray to gray: the fuel-air mixture is well adjusted - the engine operates economically.

The top of the insulator is whitish in color: too lean fuel-air mixture - check CO content; perhaps the ignition timing is set incorrectly; the control unit is faulty.

Black soot-like deposits: spark plug does not reach self-cleaning temperature (frequent driving only over short distances), incorrect heat range, too rich fuel-air mixture, too high CO content, faulty lambda probe.

Oil layer on the electrodes: defective piston rings, valve guides, or valve stem gaskets. It is also possible that you have used motor oil or fuel with additives. Replace the spark plugs, change the oil and brand of gasoline, and recheck the condition of the plugs.

(The original version can be found on the website: FordBook)