[lazer96gt]

I'm helping a friend with an EGR issue on his 4.6 F-150. So far based on the TSB on the DPFE I've swapped the DPFE, Solenoid/Regulator, EGR Valve, checked the passage on the intake, the evasporator tube, and the two tubes on the evasporator that the DPFE connects to. After clearing the MIL code p0401 comes back. I need some more help. What is left to check?

BTW I have search engined the DTC and have been going in circles.

[96greengt]

Are you 100% sure the EGR passages in the plenum are not clogged. What is the voltage of the DPFE at idle?
If it is at or near 1 volt, then the DPFE is working, if it is below .7 volts or above 1.7 then the DPFE is faulty.

To clean the EGR passages, the plenum needs to be removed to clean them, I have done 1000's of them.

[lazer96gt]

I'll check the voltage when I get the truck back. The passage I hit with TB leaner follow by an air hose. When I open the TB, I can hear the air pushing through the passage. It appears to be clear, but I guess I'll have to remove it. I'll get back.

[96greengt]

There are actually 2 passages that lead into one.

[lazer96gt]

Ok, Jody. I'm going to have the truck tomorrow. I MAY have to call you up for some assistance. So I'll be removing the upper plenum etc. to get to the passages. Once I'm sure that they are clear, then I'll proceed to voltage tests. I want to work on the passages first to ensure there will be no further issues. I'll let you know. Thanks Jody

[96greengt]

Check the voltage first, it is faster and saves you time and dirty hands.

And if I am right, I'd like dinner out of this!! lmao

[lazer96gt]

^ hey bro, it'd be worth it for sure!!

[lazer96gt]

update. dpfe voltage is within spec. although the signal is there from the dpfe, the pcm is not grounding the EGR regulator to send vacuum to the valve. I can see the egr curve(on the Matco Mentor) rise under partial pedal just as anticipated as well as the dpfe voltage fluctuate within spec. I'm leaning towards wiring, or maybe the pcm. The original dpfe which I had first removed had already been replaced with the updated unit (going by the part #). So this vehicle could possibly have a bad pcm that the previous owner would not have wanted to spend the $ to replace. I'm not going to jump the gun, but I have someone at Bluebonnet doing some research for me. We'll see.

[thatdavidkid]

good luck to you on that, its always rough getting someone to spring for something like a pcm, they're so damn hard to condemn

[lazer96gt]

Originally Posted by thatdavidkid

good luck to you on that, its always rough getting someone to spring for something like a pcm, they're so damn hard to condemn

I know. It's always the last of the last options.

[96greengt]

Waylon.... my money is still on a clogged passage.
PCM's RARELY fail now a days.

[lazer96gt]

but the solenoid nevers opens. I've driven with the vacuum gauge on the solenoid with the Mentor connected and there is NO vacuum when the dpfe rises. I had opted not to pull the intake, but I will. Also the solenoid never grounds so the solenoid is not defective. The + is there, but the ground never comes in. that ground goes directly to the pcm right? I need to find that pin on the pcm to rule out wiring.

[96greengt]

I'll have to pull a schematic to verify, but the EVR (the solenoid with the 2 wires and 2 vacuum plugs) will only see a signal at a certain RPM, 3krpm if memory serves me correctly.

How many miles will be a big factor on carbon build up in the passages?

[stangfreak]

I agree with Jody. Check the passages to make sure they are not clogged. don't be so quick to rule the pcm out.

[lazer96gt]

I will, but what would the passages have to do with the solenoid not getting ground??I can apply vacuum to the EGR valve and the truck will run ruff just as it should. So the EGR valve is allowing the exhaust into the intake.

[Stumpy]

not much i can say to this being from Acura, but i do know that a lot of the codes are read close to the same and P0401 is EGR insufficient flow on our scanners. the Acuras had a problem with the EGR port clogging on the the intake manifold. all we've done on those is take a drill bit that is the size of the port and drill out the build up. my money is with Jody. check the port again and make sure that thing is spotless.

[lazer96gt]

Originally Posted by lazer96gt

I will, but what would the passages have to do with the solenoid not getting ground??I can apply vacuum to the EGR valve and the truck will run ruff just as it should. So the EGR valve is allowing the exhaust into the intake.

^

[96greengt]

Applying vacuum to the EGR should make it stall out, not run rough, indicating the possibility of 'some' restriction if not full in the EGR passage.

Here is a picture of a bad one, you cannot see them through the throttle blade cuz the passages are on the back end of the plenum.

[lazer96gt]

Originally Posted by 96greengt

Applying vacuum to the EGR should make it stall out, not run rough, indicating the possibility of 'some' restriction if not full in the EGR passage.

Here is a picture of a bad one, you cannot see them through the throttle blade cuz the passages are on the back end of the plenum.

http://img123.imageshack.us/img123/6...9c16521hu5.jpg

well if anyone would know, you would. I THOUGHT that the engine should die, so that confirms that the intake must come off. Still though, WHY is the solenoid not gettting the ground signal?? The dpfe in communication with the pcm, but it's not actuating the solenoid. Thanks for the pic

[lazer96gt]

Also, that plenum doesn't look like the one on the truck. It is a 4.6 but that doesn't look the same. The part that is stamped in the picture you posted does not exist on this one. The mounting location of the egr is virtually flush to the plenum, and has only one hole. I now know that there is two passages internally, but I assume that your pic is only for illustration.