DPFE and EGR system Failure! Help!

[cjryan]

2000 OHV 4.0. I have a major issue with my DPFE sensor (Differential Feedback Pressure Sensor). Here is the story:

I was driving back from the mountains today and noticed that I wasn't getting as much power as I should. I was going up a hill fairly slowly (due to lack of power) and I heard an unusual hissing sound in the engine bay. I pulled over and noticed one of the hoses connecting the EGR tube to the DPFE sensor was disconnected from the EGR tube. I connected it and drove for about 50 miles before it popped off again. I did this again twice and the second time I noticed the same hose was also disconnected from the DPFE sensor.

By now the end of the hose had split at the end where it connects to the EGR tube. I pulled the extra hose slack farther over the EGR tube to make a tight as possible seal, and connected the other end of the hose to the DPFE sensor, made sure everything was snug and continued driving.

I didn't make it very far before I heard the same "hissing" again and pulled over. This time when I popped the hood I saw THAT THE DPFE SENSOR HAD MELTED!! Specifically the male plastic end where the hose connects melted from the same hose that kept disconnecting. Slight melting occured on the other male plastic end but not as much.

The disconnecting happened as higher RPM's (above 3000) at first, but then the RPM's didn't matter. I had it towed to the Ford dealer (after hours), but I am considering just replacing the DPFE sensor and the hoses and seeing how it goes. I'm concerned the EGR valve is stuck open or closed and this is the problem that wouldn't be fixed by the DPFE sensor. Please help!

Thank you for reading.

 

[2000StreetRod]

High back pressure?

What is the condition of your exhaust system? You may have high back pressure due to a blockage in your catalytic converter, muffler, etc.

There is no exhaust flow thru the tubes/hoses between the DPFE and the EGR tube. The DPFE simply compares the pressure between the two ports to determine the amount of flow thru the EGR valve. See my thread EGR System O&T

 

[cjryan]

What is the condition of your exhaust system? You may have high back pressure due to a blockage in your catalytic converter, muffler, etc.

There is no exhaust flow thru the tubes/hoses between the DPFE and the EGR tube. The DPFE simply compares the pressure between the two ports to determine the amount of flow thru the EGR valve. See my thread EGR System O&T

I have no idea. How do you check the condition of the exhaust system? I read through your thread a little last night and I knew about the DPFE just monitoring pressure. Do you think there's any chance my DPFE sensor was just clogged and this is the problem? Probably not now that I think about it if it's just monitoring pressure. I think the exhaust gases are getting backed up somehow. Will it damage the engine if I drive it short distances like this?

 

[2000StreetRod]

loose tubes

Some members have had their wiring insulation burned off by the hot exhaust gas coming up thru the loose tubes for the DPFE sensor.

I've heard that some exhaust shops have a temperature reading device that can tell if your cat is getting too hot. That would be an indication of blockage.

 

[cjryan]

Update

So the ford dealer told me that three of my four cat's needed to be replaced, they wanted $1800 for everything. I talked to a guy at a local exhaust shop and he wants $1000 to replace the cats. I also learned that the ford dealer had him come and diagnose my car!!!

The dealer said there was a "hard shell connector for the DPFE sensor". I called my wholesale parts dealer and he didn't even carry it. Is this a real part? To me it looked like the sensor was one unit, I have no idea what the hardshell connector is. Does anyone else?