Master intake gauge may also be referred as the vacuum or _______?

• A. Compound gauge
• B. Barometer
• C. Thermometer
• D. Manometer

Answer: (A)

In systems that monitor intake pressure, you need a gauge that can show both vacuum (negative relative to ambient) and positive pressure. That’s exactly what a compound gauge provides: it has two scales or dual sensing so it can read vacuum on one side and positive pressure on the other. Because a master intake gauge is used to gauge how much vacuum the intake manifold is creating (and, if needed, positive pressure elsewhere), calling it a compound gauge is the most accurate description.

Why the other options don’t fit as well: a barometer measures atmospheric pressure, not the engine’s intake vacuum; a thermometer measures temperature; a manometer measures pressure differences using a liquid column but isn’t designed for dual-range vacuum/pressure readings like a compound gauge.