Ford Mustang 1989-1993 Repair Guide

EGR Vacuum Regulator (EVR)


The EVR is an electromagnetic device which controls vacuum output to the EGR valve. The EVR replaces the EGR solenoid vacuum vent valve assembly. An electric current in the coil induces a magnetic field in the armature which pulls on a disk, closing the vent to atmosphere. The ECU outputs a duty cycle to the EVR which regulates the vacuum level to the EGR valve. As the duty cycle is increased, an increased vacuum signal goes to the EGR valve. The vacuum source is manifold vacuum.

On the 2.3L engine, a current control thermistor device is also used to compensate for extreme temperature operation. The EVR and thermistor are serviced as an assembly.


  1. Disconnect the negative battery cable.
  3. Unplug the electrical connector and the vacuum lines from the regulator.
  5. Remove the regulator mounting bolts and remove the regulator.
  7. Installation is the reverse of the removal procedure.