Question 1Motor Plants - 1st Asst/Chief

The correct answer is A) Early fuel injection. When the firing pressure of one cylinder is higher than the average, but the cylinder compression pressure is normal, it is most likely due to early fuel injection. Early fuel injection causes the fuel to ignite before the piston reaches top dead center, resulting in a higher firing pressure in that cylinder. In contrast, worn piston rings would cause a decrease in compression pressure, and high engine load or late fuel injection would not specifically lead to a higher firing pressure in one cylinder.