If im running the earlier explorer upper and lower setup on my 95 gt would not blocking off the egr holes cause any detrimental effects like issues with idle ?
So could someone correct me if im wrong but in my case having the physical holes in the lower and upper unblocked wont allow exhaust gases into the intake stream as they are blocked by the throttle body. Im kinda having a hard time visualizing how an internal egr setup is compared to the setup on my sn95 which to me is much more straight forward .
Not looking to remove the system as mine is external but my explorer gt-40 setup is internal and im in the process of hunting down a rough idle so today I removed the upper just to see if it was possible for exhaust gases to enter the intake stream. Since im not using an egr spacer the egr tunnel dead ends at the back of my throttle body elbow flange but it appears that even though it dead ends that passage is not airtight and I fear exhaust gases may have been getting either inside or outside the elbow. I was able to blow a small amount of compressed air and it was escaping at the elbow end. Im going to figure out a way to block it off. I did notice a small protrusion on the flange mating surface just below where the vacuum tree screws in at, it almost looks like it is a consequence of when the trick flow elbow was manufactured, its smoothe but like a small dimple.
On your model Explorer intake and on the Fox EFI intake the exhaust gas comes from holes in the head, through the head to the intake side, up the ports on the lower intake (middle of each side), up through the center smaller hole at the upper/lower mating surface through to the EGR spacer. The vacuum actuated valve on the back of the spacer opens when the system requests and lets exhaust gas into the intake track just behind the throttle body.
The Fox crowd if they want to eliminate the EGR simply put a plate between the throttle body and intake to block that lower hole (obviously sealed with appropriate gaskets both sides). There are parts in the aftermarket to accomplish this mainly because the throttle/cruise/kickdown cable bracket mounts off of 2 bolts on the EGR spacer. Alternatively you can leave the EGR spacer in place and simply disconnect the vacuum to the EGR valve.
On the Explorer there were 2 types of EGR elbows, one internal EGR, one external.