crdjon wrote:
Yep thats a vacuum operated EGR, I got one here in OZ on my 2007 cherokee/Liberty, actually if you look close at all the pics there are two types of 2.8l engine there, one is used in our KJ and the other is used in our JK. EXPORT ENGINES I guess. Both show vacuum operated EGR via solenoid, its pretty dumb as I just discovered, quite tolerant of conection, disconnection.
There is a bug we need to be careful of, if we use something like SEGR, we electronically satisfy everything, however on mine it is possible for the EGR to open and stay open, it is finely balanced or poor design to cause EGR to activate easily, simply unplugging it from an inactive solenoid that also has no surce vacuum applied to it activates the darn thing.
Might need some metering in the supply pipe, I think it leaks in normal operation all by itself.
With the ECU being electrically satisfied and vacuum not applied at all (disconnected) you might be ok for a while then whammo your kj sounds a bit like the beast from hell, deep throaty rumble. EGR valve comes WIDE OPEN all by itself and stays there, not always returning to its almost closed/closed state. Luckly reconnecting stuff got it back to where the valve itself thinks normal is.
SO my recommendation is be careful and alert ........ You dont get a check engine line in this mode of operation.
Now I thought the vacuum operated EGR valves were spring-loaded shut and opened when vacuum is applied. No vacuum, full spring force to close it. Guess you are of a different opinion...