High pressure can force too much fuel through the injectors.
If fuel injectors are "streaming" liquid fuel instead of a fine mist, the fuel won't burn properly, causing black smoke even if the overall air-fuel ratio seems reasonable. Common Causes of Black Smoke EXHAUST PIPE BLACK SMOKE 1.42
): The "perfect" balance where all fuel and air are consumed. Too much fuel; this is what usually causes black smoke . Lean ( ): Too much air; a reading of 1.42 is extremely lean. The "Black Smoke" Contradiction High pressure can force too much fuel through the injectors
For a deeper look at what different exhaust smoke colors signify and how to troubleshoot them, check out these expert guides: Is Your Car Blowing Black Smoke? Causes & Fixes! YouTube · The Auto Brain Too much fuel; this is what usually causes black smoke
If a cylinder fails to fire, raw oxygen and unburnt fuel are dumped into the exhaust. The oxygen sensor reads the excess oxygen as a "lean" condition (