EGR questions
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From: Kansas City, MO
EGR questions
First post, I'm sure this is a hot topic. A little background, 2000 2wd 160,0000 miles and i have some EGR questions; a while back i got a CEL, did some research and replaced the DPFE sensor from Ebay. This fixed the CEL for a couple weeks, then it came back. I was doing some more research on this today and i'm wondering if i might have a bad sensor again or if i'm looking at an EGR valve. With the Key On, Engine Off, i have a good 5 VDC reference circuit but i only have .8 VDC on the DPFE lead. From what i've read, i need a vacuum pump to test the EGR valve, which i don't have. I watched some videos on youtube on the 4 cylinder models and you can plug the hole on the EVR and the EGR valve should open and make the engine idle really rough. I did this on mine and the engine RPM's actually raised a little bit, does this point to a bad valve? Next question, the low voltage on the DPFE, is that an issue itself? I mean, i know it's too low but is it because of a faulty EGR valve?
Thanks in advance, Josh (noob)
Thanks in advance, Josh (noob)
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From: SW Va
Welcome to FTE.
Have you visited & read through the EGR links in our "Tech Info" thread, located atop this forums thread index page, to check out your DPFE sensor???? You really do have a vacuum pump, your engine, so referring to the numbers in this link from our Tech Info thread, how does the new DPFE sensor check out???? http://rockledge.home.comcast.net/~r...tage-Test.html
The EGR valve itself is robust & rarely is the cause of EGR woes, unless its rusted & falling apart. The DPFE sensor, its connecting tubing/lines, the DPFE exhaust feedback sensing port/orifice below the EGR valve, or its hose back to the DPFE sensor clogging up from carbon deposits, the EGR vacuum switching valve, then electrical problems, in about in that order, is the usual suspect line up.
Right now, without more clues, from your saying it ran ok for a while after replacing the DPFE sensor & your posted .8 volt reading, it sounds like the new DPFE sensor belongs on your suspect list. Was it a Motorcraft, or after market part????
Post up All of your trouble code Numbers, as they can offer up good trouble shooting clues & post which engine, year & miles on it.
Have you visited & read through the EGR links in our "Tech Info" thread, located atop this forums thread index page, to check out your DPFE sensor???? You really do have a vacuum pump, your engine, so referring to the numbers in this link from our Tech Info thread, how does the new DPFE sensor check out???? http://rockledge.home.comcast.net/~r...tage-Test.html
The EGR valve itself is robust & rarely is the cause of EGR woes, unless its rusted & falling apart. The DPFE sensor, its connecting tubing/lines, the DPFE exhaust feedback sensing port/orifice below the EGR valve, or its hose back to the DPFE sensor clogging up from carbon deposits, the EGR vacuum switching valve, then electrical problems, in about in that order, is the usual suspect line up.
Right now, without more clues, from your saying it ran ok for a while after replacing the DPFE sensor & your posted .8 volt reading, it sounds like the new DPFE sensor belongs on your suspect list. Was it a Motorcraft, or after market part????
Post up All of your trouble code Numbers, as they can offer up good trouble shooting clues & post which engine, year & miles on it.
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From: Kansas City, MO
Man, thanks for the reply! I will check out those links for sure. I hate to say it but the new DPFE was a $25 Ebay purchase 
. I have read about carbon build up in the oriface/tubing but i'm almost afraid to take the exhaust tube off, i've heard you can cause more trouble trying to get it off. I bought this truck a year ago and it was owned by a mechanic so it's in pretty good shape. I'm hoping a new, good- perhaps Motorcraft DPFE sensor, will do the trick. My only unknown right now is what is throwing the CEL, low voltage on the sensor? Is that low voltage a result of how the EGR valve is acting or is the sensor just bad? Thanks again for your help, i'll check out those links
. I have read about carbon build up in the oriface/tubing but i'm almost afraid to take the exhaust tube off, i've heard you can cause more trouble trying to get it off. I bought this truck a year ago and it was owned by a mechanic so it's in pretty good shape. I'm hoping a new, good- perhaps Motorcraft DPFE sensor, will do the trick. My only unknown right now is what is throwing the CEL, low voltage on the sensor? Is that low voltage a result of how the EGR valve is acting or is the sensor just bad? Thanks again for your help, i'll check out those links
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From: Kansas City, MO
Papaw, I checked out the link on testing you provided, apparently .8V is ok. I will be the first to admit, i know nothing about vacuum systems at all, so how do i apply vacuum to the DPFE to test voltages?
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From: SW Va
We aren't to have EGR feedback at idle, so we need to rev the engine then close the throttle & watch to see if the vacuum switching valve causes the EGR valve pintail to move/open.
Be mindful that your .8 volts is on the low side & we don't know how accurate your volt meter is, so for now leave the new DPFE sensor on the suspect list.
Seeing as how it ran ok for a couple of weeks after replacing the DPFE sensor, it kinda sounds like the exhaust feedback port below the EGR valve & the high temp tubing valve might be ok. Has the EGR valve on any of the EGR system components ever been replaced in the 160K thats on the vehicle?????
Does the engine use any oil????
Again, post up All trouble code Numbers you had & now have.
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From: Kansas City, MO
papaw,
to close the intake, are you talking about the intake hose going into the DPFE? would i just pinch this closed or something?
to close the intake, are you talking about the intake hose going into the DPFE? would i just pinch this closed or something?
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From: SW Va
When you rev the engine & let go of the throttle, it'll close & the engine turning at a higher than idle rpm, will cause the intake side vacuum to rise to whatever level the engine with 160K miles can produce.
I suppose you could pinch the DPFE vacuum line closed & see what effect it has, but if your looking to see if the EGR valve is being opened & closed by its controlling vacuum switching valve, which gets its operating clue from the engine computer, which gets DPFE feedback info to decide if it should have the vsv open the EGR valve, you could sorta get a rough idea if the system is working.
Why do you seem reluctant to post your trouble code Number/s????
I suppose you could pinch the DPFE vacuum line closed & see what effect it has, but if your looking to see if the EGR valve is being opened & closed by its controlling vacuum switching valve, which gets its operating clue from the engine computer, which gets DPFE feedback info to decide if it should have the vsv open the EGR valve, you could sorta get a rough idea if the system is working.
Why do you seem reluctant to post your trouble code Number/s????
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From: Kansas City, MO
Ok, cool i'll try that! About the codes, the one time i had it read was some time ago and it was the P0401. I have a company vehicle so i don't drive the truck all that much. I plan on having the codes read tomorrow while i'm off. As soon as i do, i'll post the results. I like this site, getting a lot of good information, i try to drive nothing but Fords, this being my 4th and my 2nd Ranger, definitely glad i found it 
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From: SW Va
OK, so the P0401 is an old code & you don't know if its returned or another trouble code for something else has turned the CEL on.
Good idea to have the computer scanned again before you tear into things. Most auto parts stores will scan at no charge if the CEL is lit, then post up All Numbers found.
Good idea to have the computer scanned again before you tear into things. Most auto parts stores will scan at no charge if the CEL is lit, then post up All Numbers found.
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From: Kansas City, MO
Ok, i was able to run in and get the codes read, here's what i got:
P1000- Codes cleared or battery disconnected
P0401- Insufficient EGR flow.
The first code has peaked my interest. I was reading other threads on here about this topic and people mention clearing the code by unhooking the battery for 15-20 minutes. When i replaced the DPFE, i only unplugged the battery for about 10 seconds. The code cleared but came back could this not have been long enough for the code to be cleared permanently?
I'm going to try the RPM/voltage test on the DPFE...
Ok, i have no change on the DPFE with high RPM's. I had .8V (KOEO) ran the RPM's up to a steady high level and held it there for 10-15 seconds at a time.
P1000- Codes cleared or battery disconnected
P0401- Insufficient EGR flow.
The first code has peaked my interest. I was reading other threads on here about this topic and people mention clearing the code by unhooking the battery for 15-20 minutes. When i replaced the DPFE, i only unplugged the battery for about 10 seconds. The code cleared but came back could this not have been long enough for the code to be cleared permanently?
I'm going to try the RPM/voltage test on the DPFE...
Ok, i have no change on the DPFE with high RPM's. I had .8V (KOEO) ran the RPM's up to a steady high level and held it there for 10-15 seconds at a time.
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From: SW Va
So what did it do when you let off the throttle???? That's when we should have feedback.
Check out this link on the P0401 code. OBD-II Trouble Code: P0401 Insufficient EGR Flow
It includes everything previously suggested, including a vacuum problem to, or with the EGR valve diaphragm. The code is for wimpy EGR feedback & since its vacuum operated by the vacuum switching valve, the VSV, its vacuum line to the EGR valve diaphragm & the EGR diaphragm itself at this point needs to be on your suspect list.
So come by a vacuum gauge, vacuum pump, some tubing & maybe a "T" connector & begin to do some system trouble shooting. The vacuum line from the VSV to the EGR diaphragm should be in good condition, tight fitting & holding vacuum. Same for the EGR valve diaphragm. If that's ok, check the VSV to make sure its opening ok when commanded by the computer. If all that checks out ok, suspect the DPFE sensor.
Let us know what you find.
Check out this link on the P0401 code. OBD-II Trouble Code: P0401 Insufficient EGR Flow
It includes everything previously suggested, including a vacuum problem to, or with the EGR valve diaphragm. The code is for wimpy EGR feedback & since its vacuum operated by the vacuum switching valve, the VSV, its vacuum line to the EGR valve diaphragm & the EGR diaphragm itself at this point needs to be on your suspect list.
So come by a vacuum gauge, vacuum pump, some tubing & maybe a "T" connector & begin to do some system trouble shooting. The vacuum line from the VSV to the EGR diaphragm should be in good condition, tight fitting & holding vacuum. Same for the EGR valve diaphragm. If that's ok, check the VSV to make sure its opening ok when commanded by the computer. If all that checks out ok, suspect the DPFE sensor.
Let us know what you find.
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From: SW Va
I suppose so, if they're the same. Edit: The test he was doing with the EVR was to cause it to apply a vacuum signal to the EGR valve diaphragm to cause it to Open the EGR valve & see if the engine idle would change/stumble/stall, when it opened.
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From: SW Va
You might consider reading through this thread on a P0401 EGR system trouble shoot, https://www.ford-trucks.com/forums/578271-p0401.html, as it has a number of things to look at that can affect EGR feedback the computer commands, so if any of them are feeding the computer corrupt info, or acting out, it'll have the EVR/VSV mis-control the EGR feedback. Also a blow back test to perform on the EVR/VSV that might prove positive as it did for oops.
Right now a number of things could be causing the DPFE to seem to not be operating right, so take the time to check it & the other things out, that affect how the computer operates the EGR valve.
Right now a number of things could be causing the DPFE to seem to not be operating right, so take the time to check it & the other things out, that affect how the computer operates the EGR valve.