mcjeff
Well-Known Member
- First Name
- Jeff
- Joined
- May 15, 2020
- Threads
- 7
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- 447
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- 656
- Location
- Pittsburgh
- Vehicle(s)
- 2020 JLUR
- Thread starter
- #1
Edit: Since I was asked, a “regen” is when your diesel ride burns soot off of the diesel particulate filter, or the “DPF.” Sometimes you’ll hear it called an “exhaust system cleaning.” It fills up over time and needs to be burned clean.
Edit #2: These things love long rides. I hit the expressway in Pittsburgh at 79% yesterday, and without a regen, I got off the expressway in Buffalo at 22%. Also, when I hit 800 miles between regens, it started one anyway.. even though I was only at 40% or so. Apparently they do that.
Edit #3: Your DPF and SCR system are mostly independent. While a regen may increase DEF usage, the two are mostly independent, each addressing different emissions measurements. Thus terms like “DEF regen” mix two concepts. Deleting an SCR system leaves your regen’er totally intact.
I'm now on my second JL. The first one was a 2020JLUR Pentastar that wound up having some transmission issues Jeep was never able to figure out. Thus, they offered me a discount on a new one and I ended up getting more than I paid for it on trade-in. The dealer was aware of the issue. I had originally wanted to go with the diesel, but elected not to because exhaust and regeneration requirements scared me off.
So when I ordered the replacement, I went with a JLUR diesel (14 week wait). I've had it for about a month now, so I wanted to share a few things I've noticed. If I had understood this better when I ordered my 2020 I certainly would have gone with the diesel. I obviously can’t speak to longevity or anything like that at this point! Maybe this will help someone on diesel fence decide either way.
My driving habits have actually changed since I ordered it. I used to have a ~14 mile drive to work, with more than half of that being speed-limit expressway. Now I work from home, and only elect to go in about once per week. Most of my driving is thus short suburban outings, except for that one drive to work and a lot of surface road riding on the weekend as I like to get out and explore (and I have kids to tote around).
One last thing - I can’t imagine owning this thing without a ScanGauge II installed. It makes understanding what’s going on, and planning against it, so much easier. I have mine set up to show me the distance since the last regen, withether regen is active, DPF soot mass, and turbo temperature.
Okay, all of that background aside, here are the things I think I’ve figured out in the first month or so of owning this thing.
When the soot mass hits 80% the wrangler will start an active regen. This doesn’t mean it displays a message on the dash, and unless you watch your instantaneous MPG or the RPMs at idle, you would have no idea this was occurring. It will stop on it’s own when it gets to 8%.
Regens do not require highway driving. I was Internet-convinced that I would have to jump on an expressway and drive for 30 minutes in order to clean out the DPF. Nope, not at all. It turns out that when it kicks on, it takes about 10 minutes and I can just go the long way home to let it finish. It will continue to run through stop lights, and even while you’re in “P” or “R” for a couple of minutes. Though if you stay in either of those states for too long, it will stop and pick up again when it gets back to 80%. This could be only a few minutes (if you interrupt it near the threshold), or days if it has sufficiently burned clean. The process will also happen off-road, with the Jeep in 4WD (hi or low).
Highway driving can “passively” drop DPF soot mass. I can certainly see why these are better mated to expressways. When I get up to 55-65+ MPH, the load will drop about 1% for every 15 or so miles of at-speed driving. It’s certainly happy here, but that’s usually negated pretty quickly by the surface road driving needed to get to-and-from the expressway. You’ll certainly have fewer regens overall (and thus likely a longer-lived DPF) if you’re highway driving often. I kind of view highway driving as "free driving", since it doesn't seem to increase soot load. I've not had it drop on its own on backroads.
I find it runs an active regen about once a week for me. That equates to about 3-4 miles for every percentage point of DPF soot load, adjusting for the type of driving I do that week.
Interrupting it isn’t the most awful thing. Well, as long as it gets a chance to sufficiently burn clean. If I were to stop it when it had gotten down to about 30%, it would just rebuild to 80%. If I were to stop it at 79%, it would pass the active regen threshold of 80% and continue to climb because the Jeep wouldn’t yet be up to temperature to run. This is how you wind up with the “Continue driving” console message. My guess is that most people will interrupt it, and as long as it sufficiently progresses, they’ll never have a problem.
Short drives aren’t the most awful thing. But -- you need to drive long enough for it to get to temperature and sufficiently burn down once it starts. The Jeep takes about 10 minutes of driving to get to temperature and 10 minutes to regen. It seems there’s this bad spot you can get into where you “hover” around 80% DPF soot mass, but never drive enough to get to temperature and burn clean enough.
It does smell during a regen! During normal driving, there’s no diesel exhaust smell. During a regen, there’s certainly a noticable acrid burning smell to it. My six year old asked, “why does the Jeep smell like a hot grill?” one time when I stopped it early to figure out what might happen.
There is a difference between forced, active, and passive regeneration. A "passive" isn't really a regeneration, it's just your rig getting hot enough to naturally burn off soot. There's "active", which is the process I'm talking about here. The message you'll see is the Jeep telling you to complete an active regeneration because you're in that high range. Finally, there's a forced regeneration, but if I understand correctly, only the dealer can trigger that and you've probably ignored messages leading up to this. You can have the first two processes happening and never even know it.
After all of that, I find that I can easily plan around regens since the ScanGuage II tells me what the current soot mass load is. Thus, if I turn it off and it’s above 75%, I’ll add an extra 10-15 minutes to wherever I’m going next and let it finish by itself. If I can’t afford to do that, I’ll let it burn down sufficiently far such that I know it can get to temperature before the 80% threshold during my next drive, when I can plan for it.
All in all, it seems fine as long as you don’t get stuck in that “always just around 80%”, which is when the message starts popping up and it will force you to complete one by continuing to drive. I realize that’s a long post, but in practice? It’s really just knowing I’ve got to set aside an extra 15m once a week when it’s getting close.
Oh, and get a ScanGuage II! I can't imagine having no visibility into the process. That little gadget makes it so much more manageable for me as I'm someone that likes to know the numbers and details.
Added From Replies:
@Wrangler man's pro tip: keep your DEF full if you're going off-road, otherwise you'll get inaccurate warning lights due to being off-center.
@Capricorn‘s pro tip: regens also trigger between 750 and 800 miles, independent of soot level. [mcjeff: I never go that long between; mine average about every 200 miles].
[Quick trivia: My Jeep image below was taken in the cemetery where the original Night of the Living Dead was filmed.]
Edit #2: These things love long rides. I hit the expressway in Pittsburgh at 79% yesterday, and without a regen, I got off the expressway in Buffalo at 22%. Also, when I hit 800 miles between regens, it started one anyway.. even though I was only at 40% or so. Apparently they do that.
Edit #3: Your DPF and SCR system are mostly independent. While a regen may increase DEF usage, the two are mostly independent, each addressing different emissions measurements. Thus terms like “DEF regen” mix two concepts. Deleting an SCR system leaves your regen’er totally intact.
I'm now on my second JL. The first one was a 2020JLUR Pentastar that wound up having some transmission issues Jeep was never able to figure out. Thus, they offered me a discount on a new one and I ended up getting more than I paid for it on trade-in. The dealer was aware of the issue. I had originally wanted to go with the diesel, but elected not to because exhaust and regeneration requirements scared me off.
So when I ordered the replacement, I went with a JLUR diesel (14 week wait). I've had it for about a month now, so I wanted to share a few things I've noticed. If I had understood this better when I ordered my 2020 I certainly would have gone with the diesel. I obviously can’t speak to longevity or anything like that at this point! Maybe this will help someone on diesel fence decide either way.
My driving habits have actually changed since I ordered it. I used to have a ~14 mile drive to work, with more than half of that being speed-limit expressway. Now I work from home, and only elect to go in about once per week. Most of my driving is thus short suburban outings, except for that one drive to work and a lot of surface road riding on the weekend as I like to get out and explore (and I have kids to tote around).
One last thing - I can’t imagine owning this thing without a ScanGauge II installed. It makes understanding what’s going on, and planning against it, so much easier. I have mine set up to show me the distance since the last regen, withether regen is active, DPF soot mass, and turbo temperature.
Okay, all of that background aside, here are the things I think I’ve figured out in the first month or so of owning this thing.
When the soot mass hits 80% the wrangler will start an active regen. This doesn’t mean it displays a message on the dash, and unless you watch your instantaneous MPG or the RPMs at idle, you would have no idea this was occurring. It will stop on it’s own when it gets to 8%.
Regens do not require highway driving. I was Internet-convinced that I would have to jump on an expressway and drive for 30 minutes in order to clean out the DPF. Nope, not at all. It turns out that when it kicks on, it takes about 10 minutes and I can just go the long way home to let it finish. It will continue to run through stop lights, and even while you’re in “P” or “R” for a couple of minutes. Though if you stay in either of those states for too long, it will stop and pick up again when it gets back to 80%. This could be only a few minutes (if you interrupt it near the threshold), or days if it has sufficiently burned clean. The process will also happen off-road, with the Jeep in 4WD (hi or low).
Highway driving can “passively” drop DPF soot mass. I can certainly see why these are better mated to expressways. When I get up to 55-65+ MPH, the load will drop about 1% for every 15 or so miles of at-speed driving. It’s certainly happy here, but that’s usually negated pretty quickly by the surface road driving needed to get to-and-from the expressway. You’ll certainly have fewer regens overall (and thus likely a longer-lived DPF) if you’re highway driving often. I kind of view highway driving as "free driving", since it doesn't seem to increase soot load. I've not had it drop on its own on backroads.
I find it runs an active regen about once a week for me. That equates to about 3-4 miles for every percentage point of DPF soot load, adjusting for the type of driving I do that week.
Interrupting it isn’t the most awful thing. Well, as long as it gets a chance to sufficiently burn clean. If I were to stop it when it had gotten down to about 30%, it would just rebuild to 80%. If I were to stop it at 79%, it would pass the active regen threshold of 80% and continue to climb because the Jeep wouldn’t yet be up to temperature to run. This is how you wind up with the “Continue driving” console message. My guess is that most people will interrupt it, and as long as it sufficiently progresses, they’ll never have a problem.
Short drives aren’t the most awful thing. But -- you need to drive long enough for it to get to temperature and sufficiently burn down once it starts. The Jeep takes about 10 minutes of driving to get to temperature and 10 minutes to regen. It seems there’s this bad spot you can get into where you “hover” around 80% DPF soot mass, but never drive enough to get to temperature and burn clean enough.
It does smell during a regen! During normal driving, there’s no diesel exhaust smell. During a regen, there’s certainly a noticable acrid burning smell to it. My six year old asked, “why does the Jeep smell like a hot grill?” one time when I stopped it early to figure out what might happen.
There is a difference between forced, active, and passive regeneration. A "passive" isn't really a regeneration, it's just your rig getting hot enough to naturally burn off soot. There's "active", which is the process I'm talking about here. The message you'll see is the Jeep telling you to complete an active regeneration because you're in that high range. Finally, there's a forced regeneration, but if I understand correctly, only the dealer can trigger that and you've probably ignored messages leading up to this. You can have the first two processes happening and never even know it.
After all of that, I find that I can easily plan around regens since the ScanGuage II tells me what the current soot mass load is. Thus, if I turn it off and it’s above 75%, I’ll add an extra 10-15 minutes to wherever I’m going next and let it finish by itself. If I can’t afford to do that, I’ll let it burn down sufficiently far such that I know it can get to temperature before the 80% threshold during my next drive, when I can plan for it.
All in all, it seems fine as long as you don’t get stuck in that “always just around 80%”, which is when the message starts popping up and it will force you to complete one by continuing to drive. I realize that’s a long post, but in practice? It’s really just knowing I’ve got to set aside an extra 15m once a week when it’s getting close.
Oh, and get a ScanGuage II! I can't imagine having no visibility into the process. That little gadget makes it so much more manageable for me as I'm someone that likes to know the numbers and details.
Added From Replies:
@Wrangler man's pro tip: keep your DEF full if you're going off-road, otherwise you'll get inaccurate warning lights due to being off-center.
@Capricorn‘s pro tip: regens also trigger between 750 and 800 miles, independent of soot level. [mcjeff: I never go that long between; mine average about every 200 miles].
[Quick trivia: My Jeep image below was taken in the cemetery where the original Night of the Living Dead was filmed.]
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