Mitsubishi Pick-ups and Montero 1983-1995 Repair Guide

Vacuum Regulator Valve


The vacuum regulator valve is located in the device box, which is mounted on the left-hand inner fenderwell of the engine compartment. This system is found on 2.0L and 2.6L engines.


A vacuum pump capable of producing more than 10 in. Hg (33.8 kPa) of vacuum will be needed to perform these tests.

  1. Disconnect the vacuum hose (white stripe) from the device box and connect a hand vacuum pump up to the port.
  3. Apply a vacuum of 15.70 in. Hg (53 kPa) and check the VRV condition as follows:
    1. With the engine not running, the vacuum should leak.
    3. With the engine running at 3,500 rpm, the vacuum should not leak.

  5. Remove the hand vacuum pump and reconnect the vacuum hose to the device box.

Control Vacuum

See Figures 1 and 2

  1. Locate the three vacuum hoses plugged into the back of the carburetor together. One leads to the EGR valve, one leads to the distributor and the last leads to the VRV. Disconnect the VRV vacuum hose.

Click image to see an enlarged view

Fig. Fig. 1: The Vacuum Regulator Valve (VRV) system vacuum hose configuration

  1. Connect a hand vacuum pump to the VRV carburetor nipple.
  3. Start and race the engine to make sure that the VRV vacuum increases gradually with the engine speed. If an abnormality is found in the change of vacuum, the VRV carburetor port could be blocked. Clean the port as necessary.

Click image to see an enlarged view

Fig. Fig. 2: The external vacuum connections and components of the Mitsubishi carburetor