Considering a 4Xe but have some basic questions

[Jeeperz Kreeperz]

If you look at some of the 4xe Fans videos on YouTube, a lot of work was done testing the mpg difference and it’s negligible. From what I recall, Jeep engineers were going to eliminate 2h altogether because of how little a difference it was.

It makes sense that the difference should be negligible. I’d estimate mine is actually running in 2WD 99+% of the time in dry road usage. Also, didn’t I read somewhere that the Jeep engineers used that same approach on the 392, and eliminated 2WD? Of course, that doesn’t prove that it didn’t drop MPG a bit - since 392 buyers aren’t likely that concerned with fuel efficiency

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[Dabrakeman]

There is some debate on this forum about the amount max regen helps/hurts MPG. I‘m not a big fan, and therefore don’t use it often.

The max regen mode is quite simple to understand. How much regen braking can be had at any time is a function of what the battery can handle based upon battery state (charge level and temperature) and vehicle speed. What the battery can handle does not change whether you are in max regen or not. Max regen simply sets the amount of regen braking at whatever the battery state will allow as a max as soon as you lift off the throttle. Theoretically you could get the exact same amount of regen using the brake pedal if you knew all this information in your head and could do all the calculations real time. Whenever you exceed the max level of possible regen braking with the brake pedal (whether in max regen mode or not) you will use the friction brakes and the friction brakes is a pure energy loss (I am a retired brake engineer so this always makes me sad). I always leave the max mode on because it provides a guidance to you as the driver of what that max level is and you can tune your driving to it to maximize total fregen and minimize friction braking.

 

[GATORB8]

It makes sense that the difference should be negligible. I’d estimate mine is actually running in 2WD 99+% of the time in dry road usage. Also, didn’t I read somewhere that the Jeep engineers used that same approach on the 392, and eliminated 2WD? Of course, that doesn’t prove that it didn’t drop MPG a bit - since 392 buyers aren’t likely that concerned with fuel efficiency

Front axle disconnect (FAD) is connected in 4 auto, so that's where the minor difference will come from. IIRC, FAD was new for the JL anyway, JKs were always turning.

Could exacerbate a driveshaft issue, but you could always swap to 2HI if you had vibration.

 

[Bmeister]

One of the problems with flooring the 4xe is that it puts load on a cold engine, the engine should be warmed up before flooring it.

This would be my only beef with not having an E-Save "blended option". In cold weather I want the engine up to operating temp before getting to the interstate without having to force "E-Save Charge" or manually shift the auto trans which I do now.

 

[redracer]

Agreed. On my commute, I start using e-save on back roads, about a mile before I jump on the highway (I want all available HP and torque, and that means ICE+electric). That way when I get to the on-ramp and punch it, the ICE is already warmed up. Once on the highway, I switch back to electric and leave it there for the rest of the trip to work.

I, like many others, absolutely hate the idea of the engine to be cold started and thrown into service. So I've been playing with ways to intentionally trigger the 1500rpm warmup cycle, without the engine getting engaged to the transmission.

One cheat that I found that forces the ICE to do the warmup cycle, is to tap the gas pedal while in Run / Ready and in park. When I know that I will be using gas, I just do this before shifting into D.

But, while driving, I have not found the magic bullet. Choosing E-Save will work, as long as the battery is at 95% or below and your moving above 5mph or so. Also the engine will usually pre-start when you are approaching the <1% levels, but not always as I've had it cold engage when accelerating from a stop.

I believe that shifting into manual mode on the transmission is an immediate startup and into service mode, so this isn't good.

... This should probably be it's own thread... but I've been prompted by others mentioning this

 

[Jeeperz Kreeperz]

This should probably be it's own thread... but I've been prompted by others mentioning this

No self-respecting thread in this forum can go 20 posts without at least a slight detour, so let’s veer off-road for a bit…

I believe that shifting into manual mode on the transmission is an immediate startup and into service mode, so this isn't good.

I’m not sure that’s correct. Maybe someone else can confirm. I thought shifting into manual mode WAS the magic bullet that quickly and easily forces the ICE to start. I’ve used this method before with no problems, CELs, or error codes. Although, I’ve only done this at low RPMs, so maybe trying to force the ICE on under full throttle would trigger an error?

I actually prefer this method to hitting the E-Save button, since it’s safer, as I can shift into Manual mode without taking my eyes off the road. Are you saying that switching to Manual transmission mode, while the ICE is NOT running causes some kind of error or CEL?

Below are the two pages of the hybrid supplement section of my 2021 4xe owners manual. These are the two pages that discuss Manual transmission (AutoStick mode). I don’t see any warnings about not engaging AutoStick while in electric mode. But if I should NOT be doing this, I’d like to know! Thanks.

 

[laroo]

No self-respecting thread in this forum can go 20 posts without at least a slight detour, so let’s veer off-road for a bit…

I’m not sure that’s correct. Maybe someone else can confirm. I thought shifting into manual mode WAS the magic bullet that quickly and easily forces the ICE to start. I’ve used this method before with no problems, CELs, or error codes. Although, I’ve only done this at low RPMs, so maybe trying to force the ICE on under full throttle would trigger an error?

I actually prefer this method to hitting the E-Save button, since it’s safer, as I can shift into Manual mode without taking my eyes off the road. Are you saying that switching to Manual transmission mode, while the ICE is NOT running causes some kind of error or CEL?

Below are the two pages of the hybrid supplement section of my 2021 4xe owners manual. These are the two pages that discuss Manual transmission (AutoStick mode). I don’t see any warnings about not engaging AutoStick while in electric mode. But if I should NOT be doing this, I’d like to know! Thanks.

I also use the manual mode to get the ICE started... pretty often. It never occurred to me that there was a problem with that. I'd like to see a reference for the comment you're addressing.

 

[BXFXJeep]

e-save/eSave/E-SAVE will graceful warm up the ICE before putting load on it, where as shifting to manual will fire up the ICE and immediately put load on it.

There is no error, but maybe no a best practice.

It's explained in this video, the difference between hitting e-save and chucking it into manual.

---edit
If I know I would be using the ICE anytime in the trip, I hit e-save let it warm up, then put it back into hybrid, until I'm ready to use it on the highway, or race a Civic.

 

[redracer]

Are you saying that switching to Manual transmission mode, while the ICE is NOT running causes some kind of error or CEL?

Not at all. What I'm saying is that by shifting to manual mode the engine is started and put into the drivetrain immediately. This is what I'm trying to avoid, at least when it's the first engine start, as the engine is stone cold. I'm simply trying to find the best way to cause the engine to warm up without load on it, before the jeep decides to make use of it.

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