See Figure 1
The vacuum regulator valve, used on feedback carburetor engines only, modulates the vacuum signal to the EGR valve. It reduces the signal by air bleed when the pressure applied to the regulator valve under low engine load operation.
- Disconnect the vacuum hose (white stripe) from the VRV and connect a hand vacuum pump to the VRV.
- Apply vacuum of 7.7 in. Hg and check the condition of the VRV valve.
- With the engine OFF, the vacuum should bleed off.
- With the engine running at 3500 rpm, the valve should hold vacuum.
- Replace the valve if defective.