EGR

C

Crow

Guest
#1
Howdy,
I have a 95 Mercury Grand Marquis (OBDII) 4.6 engine that there has been a P0401 code for about a year and a half; yet no running/driveability issues. Have searched this site and found a couple of things to check, one of which is in question though. That's the one regarding removing the TB and cleaning passages between the TB and egr. This engine has the aluminum intake that comes up in the rear to a 90 degree elbow facing front, then the TB bolts to that. However, the EGR valve is far below that connection and I was wondering how these "passages" were related to the TB which seems far removed from the EGR? Replaced so far: DPFE, Control Solenoid and EGR valve itself. The hoses from the tube to the DPFE are good; no leaks/cracks. There is pulsing pressures coming from both tubes. Vacuum is ok to the vac solenoid and to the EGR. However, (and I think I found the basis of my problem) when vacuum is applied to the EGR valve, there is no change in idle. Since the valve is new, that seems to bear out the clogged passages theory. Where are they and how do I get to them short of ripping out the intake manifold?
Thanks in advance.
WC
 

oldtimer53

Hero Member
Joined
Nov 14, 2006
Messages
315
Likes
0
Points
16
#2
The ports are clogged, you need to remove the aluminum elbow that connects the T/B to the intake. The EGR port dumps into a semi-circular groove in the intake at the mating surface. the groove will be full of carbon and goo. There should be three notches at quarter circle spacing along the groove, this acts to distribute the exhaust gases into the intake stream.
Shove a rag in the intake, and suck out the crud with a shop vac, as you dig it out, then don't forget to remove the rag.
 
C

Crow

Guest
#3
Thanks Oldtimer, that certainly makes some more sense! Guess I wasn't looking deep enough into the problem. I'll give that a go next.
WC