CARBURETED MODELS (PORTED EGR VALVE)
- Disconnect Green-striped hose from carburetor. Plug carburetor nipple. Connect a vacuum pump to disconnected vacuum hose. With engine coolant temperature at 113°F (45°C) or less, raise engine speed to 3500 RPM. Apply vacuum. Vacuum should bleed down.
- With engine coolant temperature at 185°F (85°C) or more and engine at idle, apply vacuum. Vacuum should bleed down. Raise engine speed to 3500 RPM. Apply vacuum. Vacuum should bleed down to about 3.2 in. Hg, then hold.
- Reconnect Green-striped hose to carburetor. Disconnect vacuum hose from EGR valve and connect a vacuum pump to EGR valve. With engine idling, apply vacuum. If vacuum holds and idle becomes unstable or engine stalls, EGR system is functioning properly.
FUEL INJECTED MODELS (PORTED EGR VALVE)
- Disconnect Green-striped vacuum hose from throttle body and connect vacuum pump to hose end. Plug throttle body nipple. With engine temperature, 140°F (60°C) or less and engine idling, apply vacuum to hose. If idle speed does not change and vacuum leaks down from EGR solenoid, system is functioning properly.
- With engine temperature 185-205°F (85-95°C) and engine idling, apply 2 in. Hg to hose. If idle does not change, and vacuum holds, system is functioning properly.
- Apply 6.8 in. Hg. If vacuum holds and idle becomes unstable or engine stalls, EGR system is functioning properly.