A system according to the present disclosure includes a first crank angle module, a second crank angle module, and a spark control module. The first crank angle module determines a first crank angle of an engine at which a predetermined percentage of fuel in a first cylinder of the engine is combusted based on pressure in the first cylinder. The second crank angle module determines a relationship between the first crank angle and a second crank angle of the engine at which the predetermined percentage of fuel in a second cylinder of the engine is combusted based on pressure in the first cylinder and pressure in the second cylinder. The spark control module adjusts spark timing of the first cylinder based on the first crank angle, and adjusts spark timing of the second cylinder based on the relationship between the first and second crank angles.