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Discussion Starter · #1 · (Edited)
Hi guys- been lurking for a while now trying to get my mind around all of this. I'm no diesel mechanic nor cumputer guru so if my questions are stupid, please set me straight.

1) If you do a DPF delete but put the sensors back in, why will it set a code -- too much air? Common sense would say that the sensor would think the filter was clean all the time and not need a regen.

2) I do the DPF delete but the computer says the truck needs a regen so it opens the butterfly on the EGR. If the passages are blocked on either end via EGR delete mod, (but the EGR is left in place) exhaust can't pass through, but the computer can still communicate to the EGR and it knows the vavle is open. It should not set a code because the device responded as it should. Best I can tell there is no flow sensor in the airsteam of the EGR assembly so it can't know that regen really isn't happening. I am assuming there is a position sensor (like the TPS) on the butterfly valve so the truck knows whether it's open or closed.

Lastly, why would you want to remove the air to air intercooler (that is the cooler you guys are talking about, right?) I thought the cooler the intake stream, the better.

(This post is in response to the thread titled Code free EGR delete and the mods that kit includes. I posted this in that thread initially, but decided to start a new thread)http://www.cumminsforum.com/forum/6-7l-performance-parts-discussion/68193-interest-code-free-egr-delete-kit.html

Okay guys -- set me straight
 

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Hi guys- been lurking for a while now trying to get my mind around all of this. I'm no diesel mechanic nor cumputer guru so if my questions are stupid, please set me straight. I may be posing this in the wrong place, but this proposed kit addresses these issues but I can't figure out why it needs to.....

1) If you do a DPF delete but put the sensors back in, why will it set a code -- too much air? Common sense would say that the sensor would think the filter was clean all the time and not need a regen.

2) I do the DPF delete but the computer says the truck needs a regen so it opens the butterfly on the EGR. If the passages are blocked on either end via EGR delete mod, (but the EGR is left in place) exhaust can't pass through, but the computer can still communicate to the EGR and it knows the vavle is open. It should not set a code because the device responded as it should. Best I can tell there is no flow sensor in the airsteam of the EGR assembly so it can't know that regen really isn't happening. I am assuming there is a position sensor (like the TPS) on the butterfly valve so the truck knows whether it's open or closed.

Lastly, why would you want to remove the air to air intercooler (that is the cooler you guys are talking about, right?) I thought the cooler the intake stream, the better.

Okay guys -- set me straight
The sensors measure pressure and by looking at the pressures, it can tell if the DPF is gone.
Why would you want to remove the intercooler? You need it.
 

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Discussion Starter · #3 ·
Why would you want to remove the intercooler? You need it.
That is my question -- and maybe the mod the kit (Code Free ERG delete) refers to is a different cooler?
 

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That is my question -- and maybe the mod the kit (Code Free ERG delete) refers to is a different cooler?
They are most likely talking about another cooler.
 

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With the EGR you want to remove the EGR cooler not the intercooler. The EGR cooler cools the EGR gases that are going back to the intake so that you aren't dumping super hot gases back into the engine.

The pressure sensors in the DPF stream measure pressure across the DPF to let the computer know how restricted the flow through the DPF is. The higher the pressure differential across the DPF the fuller it is. The computer uses this to help decide when to regen.
 

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Discussion Starter · #6 ·
The pressure sensors in the DPF stream measure pressure across the DPF to let the computer know how restricted the flow through the DPF is. The higher the pressure differential across the DPF the fuller it is. The computer uses this to help decide when to regen.
Right, so if you were to install a muffler between the two sensors, it would create differential pressure. Surely someone knows what the optimum differential should be...... It just seems to me that fooling the system into believing everything is running at optimum with all of the components in place so regen does not take place would be easier than trying to cancel and delete all the codes.

I knew there had to be a different cooler....
 
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Right, so if you were to install a muffler between the two sensors, it would create differential pressure. Surely someone knows what the optimum differential should be...... It just seems to me that fooling the system into believing everything is running at optimum with all of the components in place so regen does not take place would be easier than trying to cancel and delete all the codes.

I knew there had to be a different cooler....
He's got a point.

The diferential is done on pressure which is sent to a calculator which talks to the pooter. The tubes would have to be installed at each end. Actually, all it needs to see is a slight difference to compensate for the natural resistance built into the DPF.

But if you want to do it right then go with the BADP DPF delete and the Code Free Box. I think. . . (I have senior moments though) if the ECM doesn't see the signals long enough, it will start regenning on its own to prevent the truck from going down due to a clog. I am assuming they put in a "What If" factor.

2nd thing is the EGR delete. There is a delete kit and a few are working on a code free fooler for that too.
 

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Discussion Starter · #9 ·
if the ECM doesn't see the signals long enough, it will start regenning on its own to prevent the truck from going down due to a clog. I am assuming they put in a "What If" factor.
If that's the case, then the choices are limited.

I'm guessing Dodge used the same type system as used on their gas engines. It's a CAN based network where each sensor is somewhat intelligent. It is addressable and can report it's status when polled by the ECM. Some sensors are critical (hard code) and some are not (soft code). When the system powers up it sends a request to each device (sensor) and asks for it's status. If it responds incorrectly, or not at all, you get a code. That's why simply removing a sensor and trying to fool the system with a resistor won't work very well.

If you could leave all of the components in place, and fool the sensors instead of the ECM, mods would be much simpler. But if it has as you say a "what if things look good for too long" line of code in the logic, foolin' won't work!
 
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In a nut shell That is correct. Although I don't think they are addressable. Taht appaears to be a full anaylog system. The Sensors on the exhaust all seem to be a 4 wire, at a glance. That tells me they are working on a 0 to 5 VDC or a 0 to 10 VDC signal back to the ECM.

From what I know in setting up a gas EFI system, the O2 Sensor tells the ECM to either lean or richen the mixture. If the temp is high, the ECM leans the mixture.

In this case, they are probably reading the temperature differential as well as the pressure differential. The forward O2 Sensor could be double duty. I don't know that to be sure.

What I said earlier makes sense. If it doesn't see the sensors, the ECM may have a "What if" code in there. What if the O2 sensors are not there. Instead of the truck shutting down because of a clogged DPF, the computer could be telling the cycle "Regen until we get the sensors fixed"

I wish it was as easy as just unplugging the sensors. Those engineers are getting wise to us. :rof
 

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Discussion Starter · #11 ·
4 wire sensors suggest a CAN network. 2 wires are for network power and the other two are for communications - usually 1- 5VDC. They may be double duty sensors but I would suspect they are all O2 sensors and not pressure. They would still sense a differential of sorts if the DPF were plugged. It would be O2 instead of pressure though.

Controller Area Network - Wikipedia, the free encyclopedia
 
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There are different ways of doing it. It's been years since i wrote latter logic for PLC's But when you get down to it, the ECM is nothing more than a hardened PLC. (Programmable Logic Controller)

My specialty was heat control and robotics. But the basics are the same. The factory is going to do what is the most cost effective. That is going to be analog. Even at the volume they are doing, a penny could be saved in exchange for a fiew pieces of wire.

I saw what you are talking about in a lab back in the 90's. We were using it in Industrial controls long before the auto industry. The stuff i saw in the lab was addressable switches as an example to run the windows. Each door would only have 2 wires going to it. But the Auto companies shot it down because of cost. In the study, they figured it would shave 200 pounds out of a car.

I agree with what you are saying, but I don't think that is how they are doing it. I need to see the wiring diagrams and read the logic to be sure. But engineers are too scientific anyway.

Just cut it and lets see if it blows up. :lol3:
 

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Discussion Starter · #13 ·
I just want my 5.9 back....I'm with you on the flower pot!!
 

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4 wire sensors suggest a CAN network. 2 wires are for network power and the other two are for communications - usually 1- 5VDC. They may be double duty sensors but I would suspect they are all O2 sensors and not pressure. They would still sense a differential of sorts if the DPF were plugged. It would be O2 instead of pressure though.

Controller Area Network - Wikipedia, the free encyclopedia
There are 2 pressure switches, 2 o2 sensors and 3 Egt sensors.

The program that runs this is very complex. During regen thier is no egr gases going into the intake. Only after regen is completed does it open the Egr valve. it looks at all the sesors at once then adjusts as needed.

This means: It changes what it does or does not due at over 400 scans a minute. Which makes it hard to find what it wants or needs. You would need a program to solve the algorithm.
 
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