Jefflaws
I apprecaite you taking the time to help me out as the lord knows I need it on this one, it's driving me nuts. This is my first time really using a multimeter, so there is a learning curve here. Plus add the fact that I have just basic hand tools and a cheap OBD II scanner.

The code that started turning the MIl was a 402, after about 8 times of that I just hand checked the connectors and tapped on the EGR valve and no more MIL for about 3 days then code 401 started. Sometimes it will light the MIL, sometimes it just sets pending 401 code, and other times it will pass the OBDII test.

Here's the test readings I came up with and a shortened version of all my info/problems.
Coolant temp sensor (affects egr) got a reading of 4.65 reference volts, never could get a good ohm reading.

EVR- gets battery voltage 12.25
has an allright resistance reading of 33.2 ohms

EGR valve not sure of operation as I do not have a vacuum guage.

DPFE- This is where I get lost and think my problem might be, this is a clip from my post in a previous thread.

On my connector there is three wires, top wire is a brn/lt green, middle is gray/red, and bottom is brn/white. I know the middle is the ground or I think some call it the signal return. Now here's the problem. On that connector is a notch on the front side BOTTOM that must lign up with a lip on the sensor. They even show it that way in the Haynes manual picture but their diagram for the wire locations is flip-floped. They have the notch of the connector on the front TOP. Their words, picture, and diagram just don't match. So basically I just need to know what the top wire and what the bottom wires is.
DPFE TESTING RESULTS:
Engine running and hot, top wire = 2.84 volts
Engine off and cool (1hr cool down), key on, top wire = 2.71
Engine running and hot, bottom wire = 5.03 volts
Enine off and hot, key on, bottom wire = 5.03 volts

So I have test results but I am not sure of the wire locations. I think the bottom wire is my reference voltage and the top one is the signal. So if I get a 2+ volt reading when cold and never seem to get over a 2.85V reading when hot on the top wire which I think is the signal. The DPFE is not telling the PCM to open the EGR. Little change in voltage at any time would indicate a bad DPFE, right?

So let me know where to go from here? Should I take the new EGR valve I bought back to the parts house and get a DPFE sensor or should I get a TB gaskets and clean EGR passages in the TB. Maybe I should just give up and take it to a dealer once the light comes back on, I hate doing that. Once again a million thanks.

 

Im not sure that there is a valid test that you can do on the DPFE with a multimeter. The PCM uses the signal and the Vref and calculates a difference that you would see with a scan tool. I'm not sure how that would look just measuring the voltage on the wires. Another thing, there is not supposed to be a difference with the engine warm or cold, thats probably just an internal electronics change in resistance of the sensor, that the PCM may calculate around. The DPFE only changes it's output depending on actual pressure loss from the ERG tube when the valve opens. The best thing to do is go ahead and take off the intake elbow and take the valve off of it and clean it real good. The holes in it should be about 5/16" , so make sure you get it all out. Then , since thats "free" , if it comes back on, get a DPFE sensor. I doubt your old EGR valve is bad, so you can take the new one back if you want.

 

It should be a valid test, Haynes and Chiltons both list testing it with a multimeter but they do very in the steps.
Haynes way is to check reference voltage on Vref connector with KOEO it should be 4-6 volts and then with engine cold but running it should be .20-.70 volts of signal voltage and then it should rise with operating temps to a high of 4-6 volts.
Chiltons way is is the same but they say to use a vacuum guage hooked to the downstream pickup tube marked REF.

I have found two guys that will perform a scan with PIDS if needed for $40. I will hold on to the EGR valve to I am sure this is fixed. I work for Advance Auto, so I have located a DPFE for my truck and hope to have it on order for $65.

So you think it might be just sooted up , huh? By intake elbow I assume your talking about the elbow right after the TB that mounts the TB to the lower intake? Can you get that intake elbow ( TB elbow) gasket seperate? All I could find at work was the Intake manifold set from Felpro for $30. It didn't metion any upper or lower sets like some engines do, so I assume all the intake gaskets would be there. If Ford does sell it seperate I would appreciate a part# if you have it.

The MIL never same on all the way to work today, then came on as soon as I left work. Stopped at bank and erased and never came back on rest of today, now set a code. This is what gets me either mine is not blocked and it's the DPFE acting up or it is blocked but for some reason I am not hitting the one certain midrange spot for optimum EGR flow so in turn it doesn't see anything wrong so no DTC's.

 

Yes the elbow is what connects the TB to the intake. The gasket alone is $8 here at work, but 90% of the time i dont have to put a new one on it. Its one of those thick ones with that graphite like stuff on it. Trust me and take the elbow off and clean the 2 passages before buying any more parts. Is that $65 9J460 (dpfe) a real ford one? If not , we sell the real deal ones for 69.00 all day long.


Overall, my suggestion with any EGR code on a 4.6 is to clean the EGR passages first and drive it a couple of days to see if it fixes it, it usually does.

 

Jeff
No, I didn't buy a DPFE, I just got one ordered in case I needed it as it would take 2-3 days to get here. It's not a Motorcraft but I did cross reference the #'s, it's a GP Sorenson and I have had decent luck with their parts. But if I do use it and it fails I will get my money back and go to the local dealer who wants $76.
I now usually only get the MIl about once a day and I am aiming to fix all it for good this weekend. What all will I or should I unbolt to take the TB elbow off? Will I need to unbolt all the sensors IAC (does the IAC use a gasket?, mine looks like it does), TPS, and etc? What's the best thing to clean it with and what about that specail coating in there? Sorry just wanna be 100% sure I do it right. Thanks alot.

 

Leave the Idle valve and tp on it, just take the throttle linkage and hoses off, and unbolt the 4 8mms at the base of the elbow (leave the throttle housing on it) I clean the passages with a flat blade screw driver and then some regular aerosol carb cleaner.

 

Jeff, maybe you can help some of the rest of us out also with the egr and sensor. My 5.4 lacks power in the heat and it only seems to improve when the sensor is replaced. One weird thing also is that when this starts to act up, and it is intermintent, the idle will go up and the truck will just curise along at about 35mph all by itself. No codes and my local dealer is stumped. Any help would be appreciated. Thanks.
Terry

 

Jeff
Thanks for all your help. I find it hard to think of even reusing any gasket but I trust you and you said 90% can be reused. I hope my can or else it will have to set 3-5 days while I can get one. I might muster up the courage to yank it all apart this weekend. If I do I'll let you know how things go. I have went 1 1/2 days now without the MIL coming on.

Terry
That's a weird problem you have there, never heard of that happening with the EGR. I did notice you said something about the idle going up, could it be any fault of the IAC? Just wondering, hope you fix your problem, I know how frustrating it can be. Around here it's hard to find parts or people who know what they are doing on these newer trucks.

 

KY, you'll see that the it's a thick puffy type gasket and doesnt really "stick" to the engine

 

Jeff
Just for the heck of it I went ahead and purchased a vacuum guage as I can use it for more than just this. I think I might have found the problem but I am for sure of my readings.

When I apply 5-10 in-HG with truck at idle it does stumble and will stall. I did it as several on here suggested which is just hooking the vacuum guage to the EGR valve. The Chiltons manual indicated to pull connector off IAC, which makes the truck die, but they say to bypass this by opening throttle plate or creating a intake vacuum leak. Anyways this leaves me to think that the passages are not clogged or at least not fully.

I am still confused on the exact wires I should be measuring at on the DPFE. I assume the top wire is the signal, so that is where I placed my positive probe and the black went into the middle wire. I get a high reading at idle and with KOEO. According to a statement you made in earlier post this should indicate a bad DPFE. Here's the exact clip from http://www.f150online.com/forums/sho...6&pagenumber=2
" If the DPFERG voltage is high at idle, and is also the same highness with the engine off and key on, then you have a bad DPFE sensor"

I have never got a good reading from the DPFE, the EVR always checks out fine, and the EGR valve checked out ok too. I would think if the passages were clogged I should get a MIL on every drive I make. That may not be logical thinking but it did cross my mind.

Now does your previous advice of cleaning the elbow still hold true. I think it wouldn't hurt a thing to take it off and clena it up and I guess put a new DPFE on.

After all that, the problem should be cured. Thanks

 

Jeff and others
Well, I did as suggested and pulled the TB elbow and EGR valve off to clean them and my reastion was OMG. I couldn't believe the amount of carbon that was built up in, around and sticking out of the two EGR passages. The two passages should be about 5/16 and were restricted down to about an 1/8 is places, carbon was literally sticking out of the passages a 1/4 inch. It took me a good 2 if not 3 hr to fully clena the TB with a screwdriver and TB cleaner. I didn't feel like cleaning the EGR valve itself and had the nice new shiney one sitting there, so I put it on.
The TB mounting gasket on my 97 truck (11-3-95 engine) was not that thick of a gasket but it was the graphite coated type and seemed to be in good enough shape to reuse. I did notice a small whistle today so there mat be a small vac leak but that could be in a hose, also.
The bad news is, after I put it all back on I drove about 25 miles and then scanned the PCM and still got a pending code 401. Drove home the 25 miles and no codes, then drove 30 miles to work and no codes.

Also, at work today I sold my cheap Actron scanner. So that puts me in the market for a new scanner. I'm looking for one that does generic and manufacturer specific codes along with parameter ID's and possibly some kind of freeze frame and data logging capabilty. Trouble is I would like to keep it under $300. I have access to a laptop but it's not mine and not here so a Palm or laptop base system is not the ideal situation. I might consider a PC based system in the future as a secondary tool to play with.