that white stuff is molykote grease factorys use it for some god only knows reason i use to work in a warehouse for ford and they used it on the assembly lines. what its for i have no clue imagine to keep the arc down or something someone help me out here

 

If its grease, it really gets hard over time. My theory - and I have no proof - is that the white stuff builds up on the sensor and prevents it from measuring differential pressure properly. I am an electronics engineer and can confirm that the electronics used - thick film ceramic substrate, printed resistors, heavy guage aluminum wirebonds on the Motorcraft part are VERY GOOD quality. The vinegar will not affect the electronics. The ceramic sensor should be good as well. Frankly, Im surprised that Ford can sell this sensor - with all its electronics - for $120 retail. Goes to show you the power of manufacturing in volume.

Must be the crud - either on the ceramic sensor or plugging up the holes that is interfering with the pressure. It doesnt hurt to rub the ceramic with the vinegar and water and try to get as much white crud off of it. I took a pic and cleaned the heavy buildup in the crevices - carefully peel up the sensor and clean the sensor body on the backside too. Used drill bits to clear the ports. I sprayed the assembly off with contact cleaner to aid in drying and cleaning other crud. Make sure its really dry before closing it back up. I also used a very little amount of silicone on the rubber gaskets to make sure it gives a really good seal.

 

Didn't Ford release a revised DPFE sensor?

 

I've had to replace the DPFE in all my Ford Trucks, at around 48k miles. But I've never seen a servicable metal one, each of mine has been a small black plastic thing with two tubes and a 3-pin electrical connector, and they don't come apart (glued shut). But I was able to find new ones on eBay for $20, so not a big deal.

 

Well my repair job did not last too long... I was getting a bad idle (hesitation and weak start) so I replaced the IAC (after all I repaired the DPFE last month). That cleaned up my rough idle symptoms quite a bit but was still getting studders when the truck was idling. I also noted that the truck felt like there was a slight shuttering on hard accelerations from stop with WOT. It felt almost like a transmission problem... I decided to remove my repaired DPFE and replace it with the FOMOCO unit from the dealer. WOW - what a difference. The truck is smoother.

I think the DPFE repair helped things , but it does not compare to a new unit. I also think that if anyone is replacing DPFE, go ahead and replace the IAC as well. These 2 components work in unison to give you smooth idle.

I wished the repair worked for me but it did not. I hope others have better luck.

I also wanted everyone to know that the DPFE metal bodied units are no longer available at my dealer. I was bummed to see plastic body since the tube inlets seem to crack over time since the hoses pull on them as you are driving around. I went through 2 autozone plastic bodies with the plastic cracking. I hope the dealer part is better quality - it does come with a 1 year no questions asked warranty.

 

[QUOTE=tj90]Well my repair job did not last too long... I was getting a bad idle (hesitation and weak start) so I replaced the IAC (after all I repaired the DPFE last month). That cleaned up my rough idle symptoms quite a bit but was still getting studders when the truck was idling. I also noted that the truck felt like there was a slight shuttering on hard accelerations from stop with WOT. It felt almost like a transmission problem... I decided to remove my repaired DPFE and replace it with the FOMOCO unit from the dealer. WOW - what a difference. The truck is smoother.

I think the DPFE repair helped things , but it does not compare to a new unit. I also think that if anyone is replacing DPFE, go ahead and replace the IAC as well. These 2 components work in unison to give you smooth idle.

I wished the repair worked for me but it did not. I hope others have better luck.
QUOTE]
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I'm not sure that the DPFE had anything to do with your troubles. I was of the understanding that if the DPFE failed it would throw a CEL only, not cause stumbling on idle. If my assumption is true your rough idle was unrelated to to your DPFE.
I'm certainly no expert and understand that my circumstance may be different from yours. Does anyone more knowledgeble have more info on this?
FWIW; I'm 20K+ since I fixed mine. No CEL has returned and my truck runs good.
It would be great to hear if this "fix" worked for anyone else (besides my crew at work).

 

The DPFE is a monitoring and measureing device, reporting hardware faults by 'requested' tests from the PCM..
It has no direct control over engine control.

 

Bluegrass, please read http://www.focushacks.com/index.php?modid=80

This was my understanding of the DPFE. I can definitely attest to my old DPFE causing hesitations and "misses" at idle. I can also state from my experience that the new IAC minimized the duration and intensity of the hesitation.

I should ship you my old DPFE and you can install it on your truck so you can experience the misses and hesitation with my original unit.

 

Tell you what! unplug the device, run the motor then run the truck down the road.
You will find out it makes no difference in the running of the truck..

Again ,the device is a differencial pressure measuring device to test flow in the EGR channel and report back to the computer, readings to compare to those in a program table as a way to determine if the hardware and controlling electric/vacuum devices are capabalbe of operation within specified limits.
This is is the purpose and for emissions testing only.
The motor will run on reguardless of what happens unless the EGR is stuck open, then roughness will be the result.
Ever see two problems at once?

Trying to "fix' this sensor leaves you with no way to know if it's calibration is still as designed. It's a transducer that measures very small pressure changes accross about a .040" hole in the pipe as created by the exhaust back pressure.
Holes/ leaks etc can affect the pressure and it's detection levels causing test failures.
The DPFE is used for a number of tests at different times and different conditions that can report failures as different codes depending on the specific test routine called by the PCM..

There is enough logic used with this system that testing conditions can uncover low flow, high flow, no flow, attaching hoses off, blockages or leaking and electrical faults with the DPFE operation. So it is a very cleverly designed operation, but does not directly cause you to be stuck along the road somewhere if it fails..
It is not anywhere near enough cause to upset drivability when all that is needed is the CEL light to tell you to get it serviced without stranding the vehichle.
Did I get the point accross?

 

would a bad dpfe sensor alone be the cause of these code readings?


p1131....P11xx manufacturef controlled fuel & air metering
P0303....cylinder 3 misfire
P0304....cylinder 4 misfire
P0171 ....system to lean (bank 1)
P0401.....egr flow insufficient
P1132...P11xx manufacturer controlled fuel and air metering............

 

What year, engine, etc?

 

98...5.4 triton

 

To answer your original question, no. You have two cylinders that are misfiring, and you have vacuum leaks. How many miles on the truck and when were the plugs last replaced?

 

71k....had plugs changed around 50K................the reason I asked that question was I had a reply to the same code issue & the answers ranged from O sensors to DPFE causing cylinder misfire had iag replaced over a year ago......from major hesitation........I cleaned it ...same codes......cleaned egr....same codes.......the cylinder misfire issue is the mind boggler for me & i'm not a mechanic & (by the way it's a Van).....and I don't dare take off the fuel rail to check a coil & plugs that I can't test anyway!...LOLOL not to mention the lack of space

 

P1131 Lack of switching, sensor indicates lean, Bank 1 and P1132 Lack of switching, sensor indicates rich, Bank 1 are both Front O2 sensor signals. For Bank 1 to be both throwing both lean and rich signals from the O2 sensors says that the O2 sensors are having a hard time telling the PCM what is going on.

P0171 Bank 1 Lean is a Fuel system monitor. The P0171 can be a vacuum leak after the MAF. Check for leaks in the intake tube between the MAF and the throttle body.

P0401 is a DPFE signal indicating low flow. This too is going to be a vacuum leak.

P0303 and 0304 are simple misfires.

So, The only code that directly related to the DPFE is the P0401. Start looking for vacuum leaks!