Archive for July 2026

The Short Answer: An engine runs rich when the fuel mixture holds too much fuel for the air entering the combustion chamber. It runs lean when there is too little fuel for that air. For gasoline, the balanced fuel ratio is about 14.7:1, so a rich condition falls below that number and a lean condition…

The carburetor came off, the EFI throttle body went on, and the old pump suddenly can’t keep up. That stock mechanical fuel pump fed your carb at roughly 6 to 8 psi, which is fine for a Holley but nowhere near what fuel injection asks for. Most EFI systems want steady high pressure around 58…