Quote Originally Posted by wrencher903 View Post
ive got a 92 mighty max 4cyl 2wd. i have no vaccuum to egr. when i probe the first wire
on the harness plug to the solenoid it has power, when i ck the second wire it also has power but the
vacuum begins to work. once i remove the probe (break ground with test light) i loose
vacuum any ideas.
There should be no vacuum at idle. The functional test to see if the EGR is working properly is to disconnect the vac line with the engine warmed up and idling and apply vacuum with a handheld pump until the engine stumbles. It should start stumbling be around 5 psi. EGR helps cut down on NOx, it reburns unburned exhaust. Sometimes they get clogged with soot, if it's fouled up, take it off and clean it out with carb cleaner and a wire brush.