Ok, I'm still fuzzy on what all happened here. Did anyone ever get repeatable make/break connections without setting off the CEL?
There are a couple of ways to do this, but every combination I have tried sets the CEL on the 2nd engine start. I have not done a wait 60 second and then disconnect after coming out of park. Does that even work?
If someone has already done all of these with no luck, then that will save me time and I'll get started with plan B. That gets more involved with some circuitry, but I want to cover all the bases. Thanks.

Funny you should mention that. The Fedex man arrived this morning with a bag of samples (one harness plug and one MAF that he happened to have laying around the office from Hitachi). They look just like those on the CRD albeit much cleaner.

TurboTim, what was your plan B? I tried the sequence again over the weekend and got CEL's and I don't want to try it too many times. I'm fighting a fuel leak at the moment and don't want to push it with crank cycles... If you're thinking you're going to alter the signal level going back to the computer, you should know that we've talked about that previously and it only reduces the EGR flow (at best) doesn't remove it...

Where's that EGR mod diagram from farmdiesel, anyway. I like the plumbing solution anyway. Very "brute force"

Dan

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2005 Silver CRD Limited
245/75R16 GoodYear Duratracs
Fumoto drain | ProVent CCV Filter
Stanadyne FM100 filter | Cummins fuel pump
GDE Eco | SEGR | BoulderBars | FrankenLift | Frankenskids

I have PM'ed FARMBOSS about this mod. This guy is the essential pragmatist. I got no pictures but a very short and clear description. He left the EGR intact and apparently spliced into the CAC hose and redirected a part of the CAC air back through the EGR. I presume that he plugged off the exhaust inlet to the EGR as a part of this mod. Seems pretty simple in concept. I hate to start cutting up the turbo to CAC hose and splicing in PVC fittings to get clean air to the EGR while I am under warranty.

Doug Allen

Well, plan B (in my humble opinion) is to make an electrical equivalent of the two controlling valves (EGR & AFC), this all fed by the MAF, to keep the computer happy, while none of the real components work, thus keeping the intake clean.
Now I want to point out that this is strictly for off road testing only and that I never would suggest anyone else do something they shouldn't.
The circuit that I am currently working on is a great sprinkler timer modification, but it could possibly fool the EGR requirements for the CRD too.
The problems from what I have gleaned from all the posts is how the resistors were added in between the MAF and CPU. The problem is the MAF drives an analog voltage to the CPU. The input side of the CPU usually has a pull down resistor so it can detect if the wire breaks. The input usually goes to an analog-to-digital converter to feed the processor. The problem is/was that by adding resistors to lower the voltage, it changes the input impedance and throws the scaling off. I plan on using a few OP-Amps so that the loading/scaling stays the same until the EGR & AFC signals start to have their input effect.
The other problem with using relays on this line is that when it switches from one resistor to another, for a short time, this line goes open, thus upsetting the CPU (open is a fault condition).
No guarantees here, just a lot of analyzing that needs to be done first before the actual install.
The other thing that needs to be done is to simulate the load of the EGR & AFC so the CPU thinks they are still hooked up.
I hope some of you could keep up with this.
Many thanks to Ranger1 for his efforts, as he has given me lots of ideas here...More to come....

If you fool the computer into thinking the EGR and FCV valves are working when they actually arent, you will still get an error code because the computer will expect a drop in MAF output. Im not sure there is a way of getting the results we want without modifying the MAF signal.

The results being:

Closed EGR valve
Open FCV valve, (except during shutdown ideally)
No CEL.

_________________
It may be that your only purpose in life is to serve as a warning to others.

06 CRD Sport
Built 5/11/06
Jeep Green
Rocklizard diff cover
V6 Airbox

You are correct. My circuit is a magic box that modifies the output of the MAF with the EGR & AFC as "Tweaking" inputs. If EGR & AFC are not active, then the voltage output is whatever the MAF is. When the EGR fires off, the output will go down X %. When the AFC fires, the output will go down Y %. If both are active, then the output goes down X + Y %. Now I just have to figure out how much to drop the voltage for each ones effect. From what I have been reading, the CPU works them both to get to some magic value from the MAF. The only other input I have to work on is the signal from the transmission logic, which reminds me:

Hey Dgeist, I think I found a mistake with your logic diagram. You show using an AND gate, and the logic in park is all three switches are closed (logic level 0). The only time you will get an output is in D and TMP 4.
I think what you really wanted is an OR gate. Any logic level 1 on any line will pass through (except in park when all are at ground).

Thanks to all that have PM'd me with help. I should be making good progress this weekend. I'll keep you updated...

Yep, there were a couple problems with that original design (like using more than one pin from the TCM is not necessary and that the pin is a ground when logically "1". At some point, I might go back and fix it, but I'd rather focus on the problem than fix old diagrams

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2005 Silver CRD Limited
245/75R16 GoodYear Duratracs
Fumoto drain | ProVent CCV Filter
Stanadyne FM100 filter | Cummins fuel pump
GDE Eco | SEGR | BoulderBars | FrankenLift | Frankenskids

Ok, I need some help from some of you. I need some feedback. (Those with scanners can clear the CEL codes when done).
When I was researching the signals for the 3 components (MAF, EGR, AFC), I found that when the ORM is done, there is still a signal present on both, the EGR and AFC. Now the signals are minimal, but still present.
I made an adaptor connector for my wiring harness by cutting into the wires about 18" back from the CPU connectors (inside that plastic raceway just above the brake booster). This connector breaks the connections for all three. I have a plug with jumpers that can connect all three to put it back to stock, and none of this is visible around the CPU, or other connectors.
What I did was just leave it unplugged, so all 3 are disconnected and went for a drive. I figured all it can do is throw a few more codes. YEEEE HAWWWWWW, you guys have got to try this! I laid rubber without even trying. This thing goes! Off idle is a rocket! I don't think I'll ever plug it back in. Shifts are fine, OD still is at same shift points, just fine everything.
I need you guys to go unplug all 3 units, the MAF, the EGR, and the AFC. Let me know if you notice a difference?
By the way, as far as the AFC controlling the shudder when shutting down, it is a little more noticeable, but so what if it doesn't hurt anything. And of course, only do this off road. Back to the circuit....

Have you done the ORM with these hooked up? How does the ORM compare in performance to your mod? Laying rubber without trying hehe, I like that but I can't with my jeep, the tires stick way to much. The stockers are a different story though.

This is in addition to the ORM. In the process of seeing what signal does what when, I wanted to see what would happen if they too were disconnected. With the ORM, the CPU is still sending signals to both, the EGR and AFC. They are small pulses, but I wanted to simulate what the end effect will be if the circuit works (and that would be the EGR and AFC disconnected).
It was a very noticeable difference in better off idle performance. Better than just the ORM by itself. (Squeekin' the tires is always good). This is why I'm asking for others to try it and see if they too notice anything, or is it just me sniffing my own exhaust too much...

go Turbo, GO!!!!!!!!

watching this thread with baited breath

_________________
'05 CRD limited, SEGR, EHM, Magnaflow 18" muffler, OEM skid plates, bug guard, trailer kit, yakima cross bars and basket, CAT filter,
....more to come.....

What is an AFC? Can you provide detailed instructions on how to disconnect these wires your talking about? I wasn't able to follow your previous post. Thank you.

isn't the flow control valve - a engine turn off valve - (a safety feature to prevent runaway engines?)

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2005 CRD
stuff
Skeptic quod gratis asseritur, gratis negatur

The AFC (Air Flow Control) is an additional "Butterfly Valve" that is added on the intake manifold. On a normal diesel, there is no air valve. Air is pushed through the motor as fast as possible. Engine speed is controlled by how much fuel is added.
For the EGR (Exhaust Gas Recirculator) to work there has to be a vacuum on the intake so the engine can suck in the exhaust. On a diesel, there is no vacuum, in fact, with the turbo pushing air down the intake, the EGR by itself won't work. So, what some clever engineer did to make it work was to add this AFC valve on the entry point of the intake manifold. Now when the engine CPU says to add EGR, this valve closes part way (choking the engine), thus creating a vacuum so the EGR valve can dump exhaust in right behind this valve. (The USA is the only place they do this. Every other country doesn't have this EGR setup as it will kill a diesel engine in a short time).
The other side benefit that they use the AFC valve for it to completely close when shutting off the engine so it won't shudder. (Be aware that the Duramax, Power Stroke, and Cummings don't do this). It makes it nice for a smooth shutdown, and my circuit will put it back in for shutdown (optional).

The AFC valve is easy to spot on the drivers side of the engine, next to the battery. Just look where the intercooler hose attaches to the engine. You will see the AFC connector. Now somewhere just underneath the AFC is the EGR valve. That connector too needs to be disconnected for this test.
Try disconnecting both (as well as the MAF) and see if you notice a difference (besides 3 more CEL codes). All can be reconnected and clear the codes and you will be right back where you started. This will not hurt anything. Let me know....

Very interesting, I may try this. Just gotta track down these wires and away I go. Do you have any pictures?

Yes I have pictures, but I have no where to post them. Maybe someone can put up diagram from the shop manual, under emissions, page 25-24? It shows the component location on the side of the engine....

Can you email me the pictures? I'll send you a PM.

Can you email me the pictures? I'll send you a PM.

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2006 Liberty Sport CRD, Provent CCV mod

Thanks guys I have had the MAF and the EGR disconected for some months now I just unhooked the AFC plug and it made a noticable difference the idle rose about 50 rpm but when I drove it had much better throttle response and it seemed to coast a lot easier and farther. I will keep you all posted on any fuel mileage change since I drive my crd almost 150 or so miles a day.

Ohhh.......this could be a mod to do pronto. I drive 350 kms tomorrow, same trip about 2 weeks ago i got 38 mpg. This could be a good opportunity to see if I can get the same mileage or better?