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Discussion Starter · #1 ·
Have been driving my wife's KL more often and have noticed that when starting in cold weather it takes a long time for the idle to drop. Last night after coming out of work I tried waiting for the idle to drop... at almost 10 min later it did not. So I drove the Jeep in the parking lot without throttle to see if it would drop. I went through the parking lot at 15 Kms and towards the end of the long large parking lot the speed dropped and as I came to a stop in park ... finally the idle was below 1000rpm. Has anyone else seen this and is this normal? My truck and my sons truck at the same temp idles drop after 5 mins or less.
 

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Have been driving my wife's KL more often and have noticed that when starting in cold weather it takes a long time for the idle to drop. Last night after coming out of work I tried waiting for the idle to drop... at almost 10 min later it did not. So I drove the Jeep in the parking lot without throttle to see if it would drop. I went through the parking lot at 15 Kms and towards the end of the long large parking lot the speed dropped and as I came to a stop in park ... finally the idle was below 1000rpm. Has anyone else seen this and is this normal? My truck and my sons truck at the same temp idles drop after 5 mins or less.
just curious... did you have any of the heaters turned on? Seats, steering wheel, rear defrost... because outside temp is one factor, electrical draw is another. How old is the Jeep, and battery ?
 

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Discussion Starter · #3 ·
2014.. the seats and steering wheel have heaters.. battery I'm not sure about but tonight I'm going to put the reader to it to see if any codes are up.. and I'll test the battery
 

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yeah sometimes mine is a little weird. I just kick the throttle a little. never seems to last long. doesn't happen often. tapping the gas pedal usually brings it down. but I don't rush it, if it wants to idle a little high. sometimes while driving it's in too high a gear, who know what it's thinking. sometimes I move the stick left & nudge it back & then it thinks oh, OK I'll upshift. sometimes the little gremlins need a smack on the back of the head ;-)
 

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Discussion Starter · #5 ·
ya .. I tried all that stuff but no kick down... not until I drove it then it kicks down, so will be looking into this more tonight. We are about -16c the seats, steering wheel and rear defrost come on at start up. Look for codes, check the battery and see if any updates from the dealer are out there.
 

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My 2015 2.4 was much the same, Start idle cold was usually 1200? Went back to 750 after awhile. Never an issue putting in drive at that speed, no big clunk or anything. Always considered it "normal".
 

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ya .. I tried all that stuff but no kick down... not until I drove it then it kicks down, so will be looking into this more tonight. We are about -16c the seats, steering wheel and rear defrost come on at start up. Look for codes, check the battery and see if any updates from the dealer are out there.
-16c is pretty cold, so no wonder it wants to idle high for a while.

The engine bay and front grills on the Cherokee are designed and optimized for the bigger V6 engine, and when the smaller 2.4L is installed in there, there is too much airflow in the engine compartment, meaning the engine can't warm up as well and can't maintain optimal temp on the freeway.
To combat this, the engineers added active grill shutters that close when you approach freeway speeds and reduce airflow in the engine bay. This also helps with aerodynamics, but I believe it's 50/50 for engine temperature control and fuel efficiency.

This doesn't help you at slower speeds and when parked though, so intrinsically it takes longer for the 2.4L to warm up than the V6. It also takes longer for it to warm up than it would have taken, had the engine bay and grills been designed around the 2.4L engine instead of the V6, as is the case in the Renegade, which warms up considerably quicker with the same 2.4L engine. (my wife has a renegade, so I get to compare the two vehicles all the time)

Another factor that doesn't help the 2.4L is that it has 5.5qts of oil. That's a relatively large quantity of oil for a 4 cylinder engine, and all that oil needs to be warmed up too.

It takes considerably longer for the oil temp gauge to get to halfway than it does for the coolant gauge...

I may be paranoid, but when I start in the morning, I let the car idle for 10 seconds then gently nudge the throttle until the RPMs get to right above 3000RPM in order to get the oil circulated well throughout the engine (the 2.4L has a 2 stage oil pump which reduces oil pumping at low RPMs for fuel efficiency), then I just drive (gently for the first few minutes) away.

I live in California, so we don't get very cold temperatures unless I'm up at the cabin (5000ft). The few times when I have experienced very cold temps below freezing, I found that the Cherokee behaves very differently than normal, not just the high idle, but also the transmission behavior. It holds gears a bit longer than normally, and the gear shifts are a lot harder, almost like in SPORT, but more "sticky" which is the best way I can describe it.
 

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Discussion Starter · #9 ·
It's -33c today.. The High idle is at about 1500rpm which seems higher then it should be but I have to say I'm not experienced with small engines.. so what you say @sport_4x4 sounds about right but I'm still wondering if other factors are at play.. had to work late last night so didn't get a chance to look at the Jeep.
 

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It's -33c today.. The High idle is at about 1500rpm which seems higher then it should be but I have to say I'm not experienced with small engines.. so what you say @sport_4x4 sounds about right but I'm still wondering if other factors are at play.. had to work late last night so didn't get a chance to look at the Jeep.
1500rpm is totally normal on a cold morning until the coolant warms up a bit.
I would look at the coolant temp gauge to see at what temperature the idle goes back to the normal ~750rpm.
If your temp gets to 125-130, and the idle is still 1500, then maybe you should look into it further, but if the idle goes down to normal by then or before then, its totally normal.

Actually, idling is one of the worst conditions for an engine to be in, in terms of wear and tear. Technically, you should only be idling your engine once it's totally warmed up, and even then, not for extended periods of time.
The higher than normal idle is a good thing when it's cold. The engine warms up faster, and the oil pump is spinning faster and therefore pumping more oil through the engine when it needs it most.
That's why the recommendation is to not let any car idle until warm, but to start driving it (without pushing it hard), as it will warm up a lot faster. Less wear and tear on the car, less gas consumption, less pollution.
Now, in extremely cold climates, maybe other rules apply, but from the engine's point of view, getting going gently is the best.

Besides, the 2.4L uses 0W20 oil, which flows a lot better at cold temperatures than most other heavier oils, so adequate lubrication when cold is a lot less of an issue.

I think more of an issue is the 2-stage oil pump in the 2.4, which reduces oil flow at low rpms to increase fuel efficiency by reducing pumping losses. That's why I do the rev to ~3250rpm when it's really cold and I want to let it idle until it warms up.
 

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Discussion Starter · #12 ·
1500rpm is totally normal on a cold morning until the coolant warms up a bit.
I would look at the coolant temp gauge to see at what temperature the idle goes back to the normal ~750rpm.
If your temp gets to 125-130, and the idle is still 1500, then maybe you should look into it further, but if the idle goes down to normal by then or before then, its totally normal.

Actually, idling is one of the worst conditions for an engine to be in, in terms of wear and tear. Technically, you should only be idling your engine once it's totally warmed up, and even then, not for extended periods of time.
The higher than normal idle is a good thing when it's cold. The engine warms up faster, and the oil pump is spinning faster and therefore pumping more oil through the engine when it needs it most.
That's why the recommendation is to not let any car idle until warm, but to start driving it (without pushing it hard), as it will warm up a lot faster. Less wear and tear on the car, less gas consumption, less pollution.
Now, in extremely cold climates, maybe other rules apply, but from the engine's point of view, getting going gently is the best.

Besides, the 2.4L uses 0W20 oil, which flows a lot better at cold temperatures than most other heavier oils, so adequate lubrication when cold is a lot less of an issue.

I think more of an issue is the 2-stage oil pump in the 2.4, which reduces oil flow at low rmps to increase fuel efficiency by reducing pumping losses. That's why I do the rev to ~3250rpm when it's really cold and I want to let it idle until it warms up.
Make sense .. I'm still going to pull it into my shop and have a good look over. Check battery condition, thermostat .. etc. We are going through a lot of fuel for such a small engine so I'm thinking of installing a Wolverine heating pad to the oil pan and maybe a winter front will help too.
 

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Discussion Starter · #13 ·
Ok, I guess it's finally time to put away the shorts and flip flops. You Canadians are bada$$e$!!! Burrr!!!😮😎
My last teenager in the house was still in shorts and flip flops up till about a week ago... talk about burrrr eh! those days are long gone for me, can't handle the cold like I used to. 35 years of hard rock Mining has taken it's toll on my body.
 

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Make sense .. I'm still going to pull it into my shop and have a good look over. Check battery condition, thermostat .. etc. We are going through a lot of fuel for such a small engine so I'm thinking of installing a Wolverine heating pad to the oil pan and maybe a winter front will help too.
When the temp is below 40 degrees, the AWD system is always active in anticipation of snow/ice and the rear driveshaft is always engaged. Everyone reports a marked decrease in gas mileage when temps are below 40.

Again, I don't know if anything else is going on, but at least to a degree, that is to be expected.
 

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Everyone reports a marked decrease in gas mileage when temps are below 40.
I can confirm this. I'm noticing almost 2mpg decrease the last couple fill ups. Also depending on where you live, the winter fuel blends will have a negative impact on fuel mileage as well...😎
 

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Discussion Starter · #18 ·
It is so different from my 6.4 V8 in my Ram truck, to my sons 3.0 V6 in his truck to this 2.4 - 4 banger. So we buy a Jeep with the smaller engine to try and help with fuel consumption and these winters have a different plan and after seeing the chart @Tyler-98-W68 posted we can see why. It seems that the engine is protecting it's self and for the next few months we will have to put up with it because the temps will average in the -30's c. Life above the 55 parallel 🥶
 
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