I did it!!!!!

[passthrough]

TT,

I've been following this thread with quite a bit of interest as I have a 08 on the way. Hearing all the stuff about regen killing your mileage has me thinking about the DPF and it's functions and if getting around it (for offroad use of course) is the answer.

I had wondered the same things as you have since I learned about this DPF stuff that is on the new trucks. Whether gutting or deletion would work to eliminate regen and thus increase mileage/performance.

I have been thinking about your situation and know you have someone helping you but thought I might add a few thoughts to the project you have undertaken.

I think that your thought process is on the right track, get rid of cat and DPF and eliminate regen, leaving all sensors in place seems to make the most sense. Finding out that a couple of the sensors read temp helps as I think most were in the dark about what the sensors actually "sensed". I think you may have jumped a little quickly by gutting both the cat and the DPF though. The converter function is to burn any unused fuel (via a smoking hot ceramic honeycomb core) before it leaves the exhaust system. The DPFs function is to trap any soot that may go out of the tailpipe and when there is a sufficient amount, burn it off during regen and expell the ash that is the byproduct. Since you are having temperature issues with the sensors and the computer thnking it needs to regen the system, I wonder if you had a working converter in place if it would provide enough heat to keep the sensors/computer happy?? If you think about it, wouldn't that be nearly the same condition of the stock system right after regen?? The DPF would be clear and basically free of soot/backpressure so the before DPF sensor would be reading exhaust coming from the converter, the after DPF sensor would also be reading exhaust that passed through the now clear DPF, maybe slightly cooler but still very warm after passing through the working converter. Could it be that since you removed the heat source of the converter that the exhaust is too cool to keep the sensors happy, thus causing the truck to go into regen and effectively causing your issue??

I hope this helps or at least gets the creative juices flowing. I hope you get this issue resolved soon. I am anxious to see what kind of mileage/performance benefits this mod will give.

Glen

[TwinTurboStroker]

Glen,
I believe, you just sparked another light bulb after the many I've had go out.... my best buddy suggested that I do the same thing about a week ago, but because I was focused on the DPF so much I didn't give the cat much thought. Your idea really does seem logical and does make total sense. The fact is that the truck will come out of regen if the EGTs are hot enough, but I thought the reason it wouldn't stay out of regen was because of the pressure sensor. But as sit here and think about it the more and more it makes sense. If pressure had anything to do with it at all, the truck would never come out, I do believe that the exhaust is too cool or not getting hot enough, which would explain why the truck does not go into regen right away when I start it.....I'm going to take off work early today and run to the exhaust shop and have my buddy put a new cat on or at least order one.....thanks Glen!

[passthrough]

TT,

One other thing I just thought of. To get the EGTs high enough, you may have to induce some backpressure into the system, probably post DPF sensors. Dare I say it........A muffler A performance muffler may do the job but you may have to go back to the stock one to get enough backpressure to get the EGTs high enough to make the DPF sensors happy.

Now I know that you may not get the sound out of it you want but to eliminate the regen would be huge. And of course theres the SMOKE!!! You'd still get that though.

Glen

[pipelayerjdh]

Originally Posted by passthrough

TT,

One other thing I just thought of. To get the EGTs high enough, you may have to induce some backpressure into the system, probably post DPF sensors. Dare I say it........A muffler A performance muffler may do the job but you may have to go back to the stock one to get enough backpressure to get the EGTs high enough to make the DPF sensors happy.

Now I know that you may not get the sound out of it you want but to eliminate the regen would be huge. And of course theres the SMOKE!!! You'd still get that though.

Glen

If that be the case, you could use an exhaust brake when you need some backpressure.

[Glasseater]

Originally Posted by pipelayerjdh

If that be the case, you could use an exhaust brake when you need some backpressure.

he needs it where the dpf used to be though.. i think.. where is the more-frontal sensor anyway?

[ToddPSD]

So is it going in regen due to the lack of heat on the sensor or lack of back pressure?

If its heat, is there anyway to reinstall that temp sensor to the manifold? That is where you will get the hottest temp and keep it out of regen. But long idle times the temps might not be hot enough, maybe install the high idle mod like on the 6.0 to keep it hot enough while idiling. While your driving it should be hot enough to stay out of regen.

Just a thought?

[Maxium4x4]

OK don't ask how I got here but what an interesting thread. Since you are treading in unknown territory this is what you have to do since your problem is electrical and no one has exactly dug into the programming much on the 6.4

You are heating the probe to 700 degrees and the regen is turning off, then returning when it cools down, measure the resistance when cool then again when heated, you are dealing with an electrical source. After you find the difference simply shop at your local Radio Shack for the proper resistor.

[origcharger]

"If pressure had anything to do with it at all, the truck would never come out, I do believe that the exhaust is too cool or not getting hot enough, which would explain why the truck does not go into regen right away when I start it....."


Good luck but I would not count on these assumptions being correct and I believe your only way out is to either reinstall the cat. and DPF or hope some programmer can overcome the issue. At this point you don't even really know if there is something else wrong or your symtoms are fully the result of the DPF removal.

[Glasseater]

i think maxium4x4 has a good idea... go try it TT we're all rootin for ya!

[Maxium4x4]

The exhaust gas temperature probe is sending a signal to regen the system, defeating the electrical signal is the same as heating the probe with a torch. You know it will stop the regen cycle so all you have to do is find the resistance.