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This is my first Diesel vehicle, but I think this is an industry-wide issue. It's caused by a few things:

1) Air heated to high temperatures and pressures naturally creates NOx. The EPA demands a certain level of NOx which is partly reduced by lowering combustion temperatures.This is done by adding fuel which creates additional soot.
2) EGR is used to redirect exhaust gasses back into the motor to further lower combustion temperatures and decrease NOx.
3) The EGR gasses contain a large amount of soot which collect in the intake and other parts.

These engines are remarkably de-tuned to lower NOx and that is why the GDE tunes are so effective (and popular). GDE writes the tune to operate the engine at peak efficiency and performance with less (no?) regard to NOx. The result is higher combustion temperatures, lower soot (fewer regens), and decreased fuel consumption. Interestingly, some people see an additional 3-5MPG with the GDE tune. So, the EPA is more concerned about lower NOx than higher fuel consumption and the other pollutants that come with it..

I've read there are some upcoming vehicles (Land Rover maybe?) which put the DPF closer to the engine and take the EGR from after the DPF. This would eliminate a lot of the problems.

Riley
 

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This is my first Diesel vehicle, but I think this is an industry-wide issue. It's caused by a few things:

1) Air heated to high temperatures and pressures naturally creates NOx. The EPA demands a certain level of NOx which is partly reduced by lowering combustion temperatures.This is done by adding fuel which creates additional soot.
2) EGR is used to redirect exhaust gasses back into the motor to further lower combustion temperatures and decrease NOx.
3) The EGR gasses contain a large amount of soot which collect in the intake and other parts.

These engines are remarkably de-tuned to lower NOx and that is why the GDE tunes are so effective (and popular). GDE writes the tune to operate the engine at peak efficiency and performance with less (no?) regard to NOx. The result is higher combustion temperatures, lower soot (fewer regens), and decreased fuel consumption. Interestingly, some people see an additional 3-5MPG with the GDE tune. So, the EPA is more concerned about lower NOx than higher fuel consumption and the other pollutants that come with it..

I've read there are some upcoming vehicles (Land Rover maybe?) which put the DPF closer to the engine and take the EGR from after the DPF. This would eliminate a lot of the problems.

Riley
Hang on there... you are confusing gas and diesel vehicles... Otto cycle and Carnot cycle engines function differently.

Your first point is not totally correct. they do NOT add fuel to cool combustion temps... adding fuel causes INCREASES in combustion temps. EGR causes soot production because you are not fully burning fuel when you introduce large amounts of EG.

GDE does not lower NOx... my gut feeling is that it increases.. in some cases probably significantly depending on load.
 

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Hang on there... you are confusing gas and diesel vehicles... Otto cycle and Carnot cycle engines function differently. Your first point is not totally correct. they do NOT add fuel to cool combustion temps... adding fuel causes INCREASES in combustion temps. EGR causes soot production because you are not fully burning fuel when you introduce large amounts of EG.
I stand corrected. After further research it appears to be through lowering compression, retarding timing, and increasing EGR to provide a "buffer" of inert gasses.

GDE does not lower NOx... my gut feeling is that it increases.. in some cases probably significantly depending on load.
Correct. GDE most likely has no regard for NOx in their tunes. The GDE tunes are popular because the engines are de-tuned from factory to produce less NOx. So, by increasing timing and disabling EGR you get additional power, less soot, and increased fuel economy at the expense of additional NOx emissions.

Riley
 

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Hang on there... you are confusing gas and diesel vehicles... Otto cycle and Carnot cycle engines function differently.

Your first point is not totally correct. they do NOT add fuel to cool combustion temps... adding fuel causes INCREASES in combustion temps. EGR causes soot production because you are not fully burning fuel when you introduce large amounts of EG.

GDE does not lower NOx... my gut feeling is that it increases.. in some cases probably significantly depending on load.
May I ask what Carnot cycle engines have to do with this discussion? Or, did you mean otto cycle and diesel cycle engines? :confused:
 

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My 2015 with 56xxx miles has been to 3 different dealers, 9 times over this Service Electronic Throttle Control issue. It’s been at a dealer since 10/06/17 this round. Anyone else actually have this issue fixed permanently? FCA says their only obligation is to keep doing warranty repairs. Even though they have never fixed it at all.
Thanks
 

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My 2015 with 56xxx miles has been to 3 different dealers, 9 times over this Service Electronic Throttle Control issue. It’s been at a dealer since 10/06/17 this round. Anyone else actually have this issue fixed permanently? FCA says their only obligation is to keep doing warranty repairs. Even though they have never fixed it at all.
Thanks
You did not state what diagnostic code or codes you have. You just said it has been in Limp Mode 9 times. There are lots of reasons why. Mine went into limp mode once because my aftermarket mirror temp sensor had a bad connection, and the computer thought limp mode aka "Service Electronic Throttle" was the answer. Another time, FCA changed something in the base tune, which GDE didn't realize, and I went into limp mode in heavy Boston traffic (GDE was on the ball, found the issue within a week, and fixed the small number of tunes affected). Both times, I looked up the code with my scanner, cleared it, and continued on my way.
 

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I've had it happen a few times. When coming to a stop, you can feel the engine shake as it shuts off. Nothing weird, just normal diesel shut off vibration. CEL comes on. But then it goes away. No limp mode or anything. Just restart the engine and everything is normal and the light eventually goes away. Have not brought it to the shop. And when I say a few, I mean exactly a few; 4 or so.
 

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No idea what codes. Truck is stock, no programmer or tune. Gives Service Electronic Throttle Control in message center, and goes into limp mode. Dealers have replaced sensors. No egr or turbo replacements. Dealer flashed ECM last year, after that I lost 4-5 mpg, but problem still occurs. FCA has been less than helpful, can’t even get tool required for step 3 of repair flow chart, some pressure checker that cost $3800.
Reset did not reset limp mode this time. Step 2 checking a plug, replaced burned plug, no fix. Step 3 hi dollar tool and pressure check. That’s where I’m at since 10/06/17.
This truck is a lemon, and I missed the 12 month window. Nothing but constant issues. RSA tires were junk car tires, 6 replaced in 1 year under warranty. 2 water leaks in back seat, FCA refused to replace seats or sub woofer. Limp mode started at 1100miles, still happening at 56xxx.
 
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