plumberboy

1997 f250 light duty 4.6 about 80,000 miles.
Iam getting this po401 code. I have a new dpfe sensor, new egr valve, cleaned the ports on the throttle body, new o2 sensors, new fuel filter, new egr solinoid valve.
I still get this code......could the orfice in the egr tube be restricted or blocked?
The truck is running great. Good power not lazy from a stop.
anyone have any suggestions??? I have been messing with this for a while and now its time for emissions testing.

_Grover

Might want to check your vaccum hoses also. I had the same problem with mine. Started with the hoses, cleaned the same stuff you did and replaced the same stuff. Ended up being the dpfe sensor but did find some hoses that had holes in them.

plumberboy

Thanks Grover. We are thinking the same thing. My next move is to go out and buy a cigar and try to do a smoke test. I am not a smoker so this will be weird and a little uncomfortable.
I really think that I hear a leak on the passanger side. I used 3+ cans of carb cleaner but i can't find it.i took the 90 that connects to the bsck of the throttle body and put a light coating of permatex on it and the throttle body gasket.
Will post if and when I find something. Thanks for your reply.

plumberboy

Smoke tested today......nothing. I replaced vacuum line from the PCV to the rear of the manifold.I used nylon wire ties to clamp the ends tight. Did the same on all vacuum lines that are large enough. Used more brake cleaner and rechecked for leaks. None found. I have a new DPFE sensor but it is not a Motorcraft. Shot brake cleaner down the EGR tube in the upper branch. I have pulsing exhaust out that tube to the DPFE sensor. Tested the EGR by putting a vacuum on it at idle and it stumbled and stalled.
Anyone have any suggestions?

sbowers22

Replace the hoses that run from your exhaust to the DPFE sensor if you haven't already. My 97 had this problem for years. The original hoses would deteriorate from the exhaust causing the hoses to flake and clog the DPFE sensor. Dealers sell new silicone hoses and recently I saw some at a parts store. I replaced the hoses and replaced the DPFE sensor and have been CEL free for over 2 years now and I have over 200K on my truck.

plumberboy

Thanks, I will give that a try today. This thing is driving me crazy. Think the new DPFE is clogged and needs replaced? Any way to clean them without damage?

sbowers22

I don't think you can clean them. I probably replaced my DPFE sensor around 4 times before figuring out the problem from a post on another forum. I took a couple of them apart only to find a real fine orange powder from the hoses that clogged them up. Take those hoses off and see if anything comes out. If something does just replace everything.

plumberboy

I bought new tubes and put them in. I removed the sensor to get a better grip while sliding the tubes on. I had a couple drops of water come out. I would say that's not a good thing. Did not get a chance to drive it, too many things going on. Plus I am now out of inspection. Under cover of the night now.

plumberboy

Put the tubes on and bought a new DPFE sensor. It runs great but I have this TID $41 componentld $11 . Delta pressure for stuck open test+threshold. Can someone dumb that down for me. The value for component $11 and 12 were the same. Does this mean I still have s restriction in the 90 where the EGR connects to?

plumberboy

No vacuum to the EGR. 20"of vacuum at the solenoid and the vacuum jumps to about 5" at the EGR but drops off to 0" in a blink of an eye. Anyone have any info they can share with me?
New solenoid valve, new DPFE sensor, new EGR valve, new tubes to DPFE sensor.