EGR Vacuum Port Testing

This check is to be performed with the engine coolant temperature at 176 - 205°F (80 - 95°C).

EGR Control Vacuum Inspection:

1. Warm up the engine (coolant temperature greater than 185°F (85°C)).
2. Disconnect the vacuum hose from the throttle body EGR vacuum nipple and connect a hand vacuum pump to the nipple the hose was removed from.

EGR Control Vacuum vs Engine RPM:

3. Race the engine and note that EGR valve control vacuum rises with engine speed.


NOTE: If the vacuum does not respond as specified in the test, it is probable that the throttle body requires cleaning. Refer to FUEL SUPPLY AND INDUCTION SYSTEMS.