EGR mystery

[jdpk]

Hi all,
I have been battling 401/402 codes for a good while and need some help. Recent (1500 miles) the 2002 winnie van exhibits slight to moderate bucking at around 1500-2000 rpm. Sometimes worse when cold, sometimes worse when hot. It threw out the 401/402 codes a while back but I had already replaced EGR, DPFE, and done the P0174 Leckemby repair last year. From what I gather from searching this great forum, there is a vacuum issue somewhere. I have searched around for leaks but have not found anything obvious. I checked the voltage at the DPFE sensor and the Haynes book says it should have 5 v at igniton on (it does) and no voltage when started and still cold (voltage stays same) then kick to 5 v when hot (still 5v). Now wondering if DPFE is working properly, just getting bad info from PCM. Is it too far of a reach to suspect the coolant temperature sensor as a possible culprit?

[catvents]

Originally Posted by jdpk

Hi all,
I have been battling 401/402 codes for a good while and need some help. Recent (1500 miles) the 2002 winnie van exhibits slight to moderate bucking at around 1500-2000 rpm. Sometimes worse when cold, sometimes worse when hot. It threw out the 401/402 codes a while back but I had already replaced EGR, DPFE, and done the P0174 Leckemby repair last year. From what I gather from searching this great forum, there is a vacuum issue somewhere. I have searched around for leaks but have not found anything obvious. I checked the voltage at the DPFE sensor and the Haynes book says it should have 5 v at igniton on (it does) and no voltage when started and still cold (voltage stays same) then kick to 5 v when hot (still 5v). Now wondering if DPFE is working properly, just getting bad info from PCM. Is it too far of a reach to suspect the coolant temperature sensor as a possible culprit?

Did you install an aftermarket DPFE or a genuine part from Ford ? Having got this problem (401/402) including a bad pinking situation I have install and aftermarket DPFE and the 401/402 were back again. I have cleaned the EGR, the DPFE tube, replaced the temp sensor, and the EGR vacuum regulator but unfortunatly the code remain there until I have replaced the aftermarket (new) DPFE with a Ford unit.

[jdpk]

catvents;
Very interesting that the last fix was motorcraft DPFE. I did indeed go the 'cheap' route and use an aftermarket DPFE. I have a very friendly Ford parts dealer who does not rack me list price for parts, so I may as well try it.
Thanks,-
Update--thebloody CEL went off today but still bucks and shudders as it has. Does the CEL normally go out on it's own???? Crazy.

[jdpk]

Dumped $60 amerikan on a genuine Motorcraft DPFE. Will post results after drive cycle or CEL, which ever comes first.

[catvents]

Originally Posted by jdpk

Dumped $60 amerikan on a genuine Motorcraft DPFE. Will post results after drive cycle or CEL, which ever comes first.

If you are not using a scan tool and are unable to light off the CEL, remove the neg terminal of the battery for about 10 seconds this will clear the codes.
I do not have the book in front of me but if I remeber it needs 2 or three complete cycles ( engine heat and drive for a while) before the CEL goes on if this malfonction is still there. ( hope not for you). Let us know

[Andrew1941]

I have a 2001 3.8L Sport and it is doing the EXACT same thing JDPK describes. I have not gotten a code reader yet, but I too have done the other repairs and I was good for a few months, but last week it started this bucking/hesitation at about 1800 RPM in 4th gear going to 5th under slight loading, i.e. uphill. It will not do it on the flat or downhill or under heavy load. After about a week of it doing this, the CEL came on and has been on for about a day or so. The fuel mileage is good. I will find out the codes and see what it says....hopefully someone can get to the bottom of this. I hate to just start changing parts guessing which one to change next.

[catvents]

Carbon buildup on the EGR ports inside of the intake plenum is often the cause of this type of hesitation on light load. I think no code are associated to that except that it is part of the po171/174 job. Take a look on that if you have not seen it:
http://leckemby.net/windstar/windstar01.html

[wiswind]

Dirty EGR ports can cause P0303 and / or P0304 miss fire on cylinder(s) 3 and / or 4.
This is what happened when my EGR ports clogged...
This happens when the EGR system opens up...and the EGR flow is going to just 1 or 2 cylinders......causing them to not have enough oxygen.

The EGR ports normally clog closest to the EGR valve first......and the ports farthest from the EGR valve are the last ones open.

The pictures that the link in my signature takes you to show the EGR ports.
This is one of my first projects with my vehicle when I had a digital camera....so they are right there on the first page of the pictures.

Sadly, the only way to clean the ports is to remove the upper intake manifold and manually clean them.

[mannyjfk]

Will some SeaFoam clean that? I just did the job and I am not sure if my mechanic cleaned them the right way. I heard many things about SeaFoam but I dont know if they are true or not.

[wiswind]

I do not think that seafoam or any other product sprayed into the intake will do much at all to clean the EGR ports.
NOTHING added to the gasoline will.....as gasoline does not reach the EGR ports.

[Andrew1941]

In the P0174 fix posted, he talks about using a pick to clear the ports of the carbon build up, but when I did my 2001, the ports barely had anything in them (at least at the opening). When I opend my sister's 2002, there was lots of build up. In both cases, I used a cue-tip with throttle body cleaner to wipe the build up out. Would I have to clean anymore that just the opening, i.e. further down past the hole? and if so, how?

[catvents]

Originally Posted by Andrew1941

In the P0174 fix posted, he talks about using a pick to clear the ports of the carbon build up, but when I did my 2001, the ports barely had anything in them (at least at the opening). When I opend my sister's 2002, there was lots of build up. In both cases, I used a cue-tip with throttle body cleaner to wipe the build up out. Would I have to clean anymore that just the opening, i.e. further down past the hole? and if so, how?

You did the job correctly. The carbon is located just on the orifice of the EGR ports, not deeper, so if you clean what you have seen it is correct.

[wiswind]

Mine was also just right at the opening..
Seems it forms right where the dry exhaust meets the oil vapors in the intake.

[jdpk]

THe new DPFE seems to have little effect. The bucking actually worsened as I drove to the airport following the installation of the new motorcraft DPFE. It sat in long term parking for 6 days, lit it off to come home yesterday and the bucking remained. Mileage still looks good, 23 mpg on short (60 miles)highway drive home. I have cleaned the ports when I did the intake job last fall, there did not appear to be much crud there, but I removed what there was. Still searching for answers.
No CEL yet but the cycle maynot be done. Wife getting impatient with my lack of success-she's threatening to take it to dealer which I am dreading ($$$$$)

[wiswind]

A good test that you can do to determine if it is the EGR system causing this bucking......
Remove and plug the vaccum line that goes to the EGR valve.
Drive the vehicle......Does it still buck?.....if so....then it is NOT the EGR system.
If it does not buck.....then it is caused by the EGR system.

I would recommend doing this......to make sure that you are not looking the wrong direction.

This is only a temporary test.....and should cause the CEL to be on indicating a lack of EGR flow......which is correct as you have disabled the EGR system.
So you are looking for the bucking to go away....or still be there.

If it is still there.....then I would look at dirty fuel injectors as a possible cause (a can of Berryman's B-12 Chemtool in each of the next 2 - 3 tanks of gasoline).
Figuring that your coil pack and spark plug wires are in good shape.

It is possible that you have several issues....and this test will help determine if the bucking and 402 codes are truely connected.

Also....give the EGR pipe (goes from the front exhaust manifold to the EGR valve) a looking at....as well as the hoses that go to the DPFE.