EGR Related Issues - Cant figure it out!

[Justin1985]

I recently acquired a 1996 explorer XLT (v8) and have been trying to get it to pass inspection. My check engine light is on and am getting the p0401 code for insufficient flow to EGR. Here's what I've done so far to attempt to remedy the situation.

Replaced EGR Valve (old one was frozen with carbon buildup)
Replaced EGR Solenoid.

I'm still getting the code and am at a loss. When I pull the connector to the solenoid off, I get a vacuum that easily feel with my finger. When I leave the hose covered with my finger, I can hear the RPM's drop slightly. I don't have any real mechanic tools or experience and my brother who's been a parts man for 10 years usually has an answer for me but he doesn't in this case. The previous owner said the issue has been ongoing and nobody could figure it out.

From other posts I've read, the EGR valve should not move while idling but only when up to speed. I've tried revving the engine to get it to move but still nothing. But like i said, I'm a newbie and that may be normal.

Also, I disconnected the small hose from the solenoid to the EGR valve and could feel very little from that. I'm not exactly what I'm feeling other than a slight tickle. Agaoin, that may be normal, I don't know.

When I replaced the EGR valve, there was no gasket or o-ring between the valve and the EGR position sensor but I could see a recessed area that looks like there should have been one. Rock Auto shows the replacement part with an O-Ring. (I found a post earlier that that missing O-ring was the culprit for the EGR valve not functioning properly.)

My last bit of amateur troubleshooting was blowing into the vacuum hose that I could feel suction on (coming from solenoid) while the engine was not running of course, as an attempt to see if I could detect any major leaks in the hose. I was able to pass a small amount of air through the hose but not very much at all. I'm not sure if this is normal. Should I be able to blow into it at all?

I am at a loss as to my problem. I'm leaning towards a missing O ring on the EGR position sensor but I'm no mechanic. Any help would be GREATLY appreciated

 

[1998Exp]

The EGR opens under specific conditions; fast idle may not be one of those.
It's been a long time since I had this setup with a position sensor on top of the EGR valve, and don't remember whether the O-ring seals vacuum or not. If it's supposed to do that, it could indeed be your problem.
Obviously, the sensor itself could be bad. Those don't really measure any EGR flow, and simply indicate the position of the EGR valve -- whether anything is flowing through it or not. That type of sensor is just a potentiometer (a resistor with a moving contact, attached to the shaft). In my older vehicles the shaft would sometimes get stuck, indicating an open valve, when in fact it was closed. I used to check those by hooking up an ohmeter to the proper pins, gradually applying vacuum from a hand pump, and watching the resistance. If you don't have a vacuum pump, you can remove the sensor, and simply move the shaft by hand. You can probably find the pinout and the resistance specs on line. If you can't, I will look it up in my old book.
If you don't have a multimeter, it's a good investment for anyone who wants to work on their own vehicle (and on just about anything electrical). Basic ones can be had for as low as $10-$20. In fact, I just got a mailing from Harbor Freight, with a coupon that gets you one of those for free - no idea how good they are...

Another way to read the sensor position is with a scanner, but I am assuming that you don't have one.

I recently acquired a 1996 explorer XLT (v8) and have been trying to get it to pass inspection. My check engine light is on and am getting the p0401 code for insufficient flow to EGR. Here's what I've done so far to attempt to remedy the situation.

Replaced EGR Valve (old one was frozen with carbon buildup)
Replaced EGR Solenoid.

I'm still getting the code and am at a loss. When I pull the connector to the solenoid off, I get a vacuum that easily feel with my finger. When I leave the hose covered with my finger, I can hear the RPM's drop slightly. I don't have any real mechanic tools or experience and my brother who's been a parts man for 10 years usually has an answer for me but he doesn't in this case. The previous owner said the issue has been ongoing and nobody could figure it out.

From other posts I've read, the EGR valve should not move while idling but only when up to speed. I've tried revving the engine to get it to move but still nothing. But like i said, I'm a newbie and that may be normal.

Also, I disconnected the small hose from the solenoid to the EGR valve and could feel very little from that. I'm not exactly what I'm feeling other than a slight tickle. Agaoin, that may be normal, I don't know.

When I replaced the EGR valve, there was no gasket or o-ring between the valve and the EGR position sensor but I could see a recessed area that looks like there should have been one. Rock Auto shows the replacement part with an O-Ring. (I found a post earlier that that missing O-ring was the culprit for the EGR valve not functioning properly.)

My last bit of amateur troubleshooting was blowing into the vacuum hose that I could feel suction on (coming from solenoid) while the engine was not running of course, as an attempt to see if I could detect any major leaks in the hose. I was able to pass a small amount of air through the hose but not very much at all. I'm not sure if this is normal. Should I be able to blow into it at all?

I am at a loss as to my problem. I'm leaning towards a missing O ring on the EGR position sensor but I'm no mechanic. Any help would be GREATLY appreciated

 

[Bark]

I had tons pf issues with my DPFE. I heard there was one that had a new harness for the new style dpfe. I was lied to. I had to get a new plastic dpfe and shave off the tabs to put the old harness on upside down. I checked the signal ground and reference and zip tying the old harness upside down on a new DPFE did it.

 

[Explorin'VA]

Motorcraft does make a new harness that's included with the new style dpfe. I just replaced mine and it involves cutting your old harness off and splicing the new one on. My truck has been stalling out when rolling to a stop. I had codes indicating a bad dpfe, egr valve, and egr vacuum control switch. I was able to get rid of the dpfe code by replacing the sensor, but still need to get rid of the other two codes and make sure replacing the valve and switch fixes the stalling issue. The confusing part is that all the egr valves listed for the explorer have 2 holes on the side that allow air to escape. There's actually an egr valve listed for a 97 mustang that is the same valve as the explorers, but without the 2 holes. I ordered the egr valve listed for the mustang and the switch. When they arrive tomorrow I will see if the egr valve is the correct part, and if so I will post the part # in case anyone else is dealing with the leaky egr valve that all the parts stores are selling for the explorer.

 

[Turdle]

96 has no DPFE, it uses an EGR position sensor. I suspect it is bad.

 

[Justin1985]

So after multiple resets, I found that the first time I drive it, I can drive as far and long as I want with no Engine Light. If I turn it off then on again, its back on in under 2 miles. I used this to my advantage today to pass inspection. I drove it about 30 miles, pulled into the mechanic, and left it idle. He did his inspection and it passed. When he parked it, I paid, and got back in, I drove to the license plate agency and check engine light came on.

I guess I've got a year to figure it out again but I'm gonna stay on top of it. I am going to get the position sensor today and change it out. I'll let you all know how it goes.

 

[accountanne]

Please do because I am having same problem. Can I ask you what tools you used to get the EGR valve out? There is not a lot of room there to work that's for sure.

 

[Justin1985]

I have it figured out. It was a missing o-ring on the position sensor. I just got another 96 explorer 5.0 V8 Eddie Bauer and had egr excessive flow on that one. I ordered new EGR and 2 position sensors (one for the other explorer). Took off the egr on the new vehicle and saw that it had a pretty specific looking o-ring (between the sensor and egr valve). I took that off and pressed it into some sticky tack to get a mold, peeled it out and made a copy with some rtv gasket maker. I worked like a charm! Used a 13mm stubby ratcheting wrench for the bottom bolt and 9/16 socket for the top bolt. Remove metal bracket holding solenoid and tranny dipstick. Now I just have to figure out my A/C.

 

[morbid81]

have you checked your egr tube they are prone to crack and leak on the v8's.

 

[Turdle]

have you checked your egr tube they are prone to crack and leak on the v8's.

1996 has no egr tube, as it is an internal egr system. Late 97 was the introduction of GT40 p heads with external egr