Equus 591-221 Specifications
- Functions: Dual-purpose gauge reading vacuum levels up to 30 inHg (inches of mercury) and fuel pump pressure up to 10 psi.
- Visual Interface: Dial face featuring color-coded diagnostic zones to help you read vehicle conditions at a glance.
- Included Kit Components: A flexible, heavy-duty hose along with standard tapered adapters to attach directly to various engine vacuum lines and fuel system ports.
Interpreting Your Equus Gauge Readings
To diagnose mechanical engine health using the 591-221, monitor how the needle responds when connected to a manifold vacuum source at normal operating temperature:
- Steady 17–22 inHg: Indicates a healthy, normally functioning engine with solid timing and no major mechanical leaks.
- Low Steady Reading (below 15 inHg): Point to an intake manifold leak, bad carburetor/throttle body gaskets, or late ignition timing.
- Needle Drops Intermittently: Typically signals a sticking or leaking valve that fails to seal completely when the cylinder fires.
- Rapid Needle Vibration (Fluttering): Points toward worn valve guides or a potential ignition system misfire.
What symptoms is your vehicle showing? If you share the exact needle behavior (e.g., vibrating, low steady) you are seeing on the Equus gauge, you can narrow down the exact fault.