Pesky Codes
 

Ok, so this is my first post here so please bear with me. I have been reading threads and posts for several weeks and learned alot.....Thanks to all.
I have an 07 350 Crew Cab with 114,500 miles...I have owned it for the last 7k. It has an aftermarket intake elbow (not sure brand), Amsoil bypass system and straight pipe (cat is still there). As far as I know that is all that is not factory. I put the bypass filter on about 3k miles ago and at that time I also changed both fuel filters and cleaned the EGR valve.
The check engine light is on right now and according to the scanner at Auto Zone it is P0404 and P0405 codes. It may stay on for a few days then it will go off for a day or so then come back on. If the light is off it seems as though it may come on under a heavier load...going up a long hill with a heavy foot This has been going on for several weeks now. No drivability issues.......it just annoys me the light is on. Ideas......?

It's definitely EGR codes. Can you look to see if the EGR cooler is still there? What did the EGR valve look like when you took it out to clean it?

Egr cooler is still there. When I had the valve out it was sooted up pretty heavy although from pictures I have seen of dirty ones it really wasnt to bad.

The EGR valve itself could simply be dying... maybe try and scoop one up on one of the powerstroke boards, I'm sure there are plenty of good one's out there for cheap. They're a little pricey from the dealer though...

Is there any way to test the egr valve with a meter or anything? How many volts activate it?

I can't answer that for you... typically when people have issues with them they throw them away with a delete kit. You could always get an SCT tuner and get tunes that have the EGR function shut right off :c:

Delete kit is in the future plans. I have 3yrs or 35k left on Ford ext. warranty so I am sort of waiting for that to expire before I make any major changes. From what I hear though it seams as though warranty claims are often hard to deal with....as well as a good Ford diesel mechanic being hard to find. That is why I try to do as much as I can myself.....with alot of info gleaned from sites like this....

What drivability issues would I see if the EGR valve was not working?

You could see and feel it at lower speeds and high boost situations, at lower speeds you would have no acceleration and be blowing black smoke, it would run like crap, and on higher boost like pulling a hill or towing it wouldn't make good power because the boost could be escaping back out the weak EGR valve and probably making a cloud behind you..

Interesting....just today when pulling away from a stop light there was a slight hesitation..maybe 10 seconds with the pedal pressed and almost zero acceleration and when I looked in my side mirror at tailpipe there was a small cloud of black smoke. Awhile later I was accelerating and it started to buck just for a few seconds then took off like it should. It seems like the EGR valve may be going bad.

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Mdub, why SCT verses other tuners?