Manifold pressure is being discussed. Technician A says manifold pressure may be pressure that is lower than ambient pressure. Technician B says manifold pressure may be pressure that is higher than ambient pressure. Who is correct?

Question

Quizplus · Accepted Answer

Manifold pressure can be lower than ambient pressure when the engine is under vacuum (such as at idle or low throttle), and it can be higher than ambient pressure when the engine is turbocharged or supercharged.

Manifold Pressure Is Being Discussed