RESOLVED: sudden High Idle?

[Wrangler man]

Actually I was addressing the references (by others) to temperature and regen status. Both of which are readily determined with the addition of a gauge.

I agree, Jeeps don't need tachs (especially the ecodiesel ), but faster-reving engines are riskier to shift by ear.
[/QUOTE
Under normal operating conditions a tach is generally not needed. If you're unable to fully warm up the equal diesel it's a good idea to keep the revs under 2000 without the tach this would be difficult. When traveling through the steep mountain roads fully loaded which I might be exceeding the payload load. I occasionally use manual mode on the trans, utilizing engine breaking, avoiding brake fade caused by hot pads and rotors Glad the tach is there under those circumstances as well.

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[Petey]

nothing noted at the exhaust.
i've found stories about a Throttle Body Error on the previous Gen EcoDiesel boards, but i don't know if that applies to our Gen3s, and the symptoms don't seem to be the same.

i'd expect that if it were getting additional fuel from a 'leaky' injector it wouldn't run very smooth; this thing seems like it's running smoothly, just idling too high.

Not necessarily fuel form injector ..are there throttle bodies on these these things ? anyone?

 

[JL ME]

yeah, nothing low, lumpy or 3.6 here.

That docent mean doing what i suggested may not clear up your problem.

 

[zouch]

if that were to clear up a problem, i think it highly unlikely that would clear up any more than a symptom of the true Root Cause problem.
i'm interested in Root Cause.

That docent mean doing what i suggested may not clear up your problem.

 

[JL ME]

if that were to clear up a problem, i think it highly unlikely that would clear up any more than a symptom of the true Root Cause problem.
i'm interested in Root Cause.

Good luck.

 

[zouch]

update:

TL:DR
Unresolved.

Dealer had it for a couple of days and can't figure it out. (not a huge shocker there.)
they've opened a Star Case to try to get the national-level Tech crew involved; they can't figure it out. not sure if that pulls in @JeepCares or not.

there are reportedly no codes in any module, nothing weird found in the High Pressure Fuel Pump or any of the filters.

at this point they've said they want to start out with a fresh tank of new fuel with no additives, so they want me to burn off the half-tank that's in it, then fill it and drive it some more. pretty weird since this thing is in regular use and the only additive i've ever put in it is the Mopar Fuel treatment.

so basically; just drive it, and see if it goes away; call us again if it doesn't. ?

have i mentioned how unimpressed i am with the diagnostic skills i've seen from J**p?
to send someone out on the road with a vehicle that requires extra brakes to slow it down in traffic and hold it still at a stop (while it sits there and chews on its torque convertor) seems a little 'off'.
but maybe my expectations are too high..?

 

[garykk]

I know this may be a shot in the dark but as mentioned before, a faulty temp sensor. Not sure about these diesels but does the rpm increase when The AC is on?
it seems you’re not alone with this. https://www.wranglerforum.com/threads/eco-diesel-cold-idle.2409748/

 

[zouch]

thanks.
i appreciate the shot.

issue here doesn't seem to be the same as the Cold Idle described in that linked thread; mine is starting out @ ~1100-1200+ RPM and never going below about 1050 RPM even after running for hours (like i did with it today).
no perceptible difference related to A/C operation.

following up on my post from this morning, i spent a few hours wasting fuel on the hwy and ran it down to where it wouldn't even report how many miles of range it had left to go and put 17+ Gals of plain #2 in it. drove it around for a while afterward to make sure that 'fresher' fuel had worked its way into the system, and it works exactly the same; no difference.

i did leave the ESS engaged today just to to to leave things as 'normal' as possible. (i usually only leave ESS engaged one day a week or so just to keep it all working, but otherwise hate it.)
it seems to me that it did not shut down the motor as often as i recall it doing, but that could be a misperception on my part because i don't usually leave ESS engaged and might not remember exactly how it works "normally".

I know this may be a shot in the dark but as mentioned before, a faulty temp sensor. Not sure about these diesels but does the rpm increase when The AC is on?
it seems you’re not alone with this. https://www.wranglerforum.com/threads/eco-diesel-cold-idle.2409748/

 

[garykk]

Just a thought but if the temp sensor was defective, the idle would not return to normal.

 

[zouch]

could be. i don't remember how high mine would idle cold before this happened; i don't remember it being as high as it is now.

i'd hope that if that temp sensor was wonky it would throw a code, otherwise i'm afraid the guys at the dealership would never find it,.. i'm not sure how i could check it myself.
i'd also hope that by the time they got a Star Case assigned to it someone would have made sure anything that simple was checked. perhaps i'm expecting too much?

i guess we'll see!

Just a thought but if the temp sensor was defective, the idle would not return to normal.

 

[Ratbert]

could be. i don't remember how high mine would idle cold before this happened; i don't remember it being as high as it is now.

~1,100 cold and ~750 warm.

 

[zouch]

interesting.
mine started out this morning and i'd swear it was at about 1350 or higher before it settled in at ~1050.

seems like mines a few hundred high no matter what.

~1,100 cold and ~750 warm.

 

[zouch]

Gary,
sorry; looking back at this and just realized i didn't address the second question.

no, there doesn't seem to be any change to RPM when the AC is on. (i typically have the Climate Control set on Automatic all the time anyway, so wouldn't necessarily know when the AC was engaged or not.)

current status; issue remains Unresolved.
Dealer doesn't have a clue, but wants me to bring it back again this week now that i've burned through yet another tank of fuel.

I know this may be a shot in the dark but as mentioned before, a faulty temp sensor. Not sure about these diesels but does the rpm increase when The AC is on?
it seems you’re not alone with this. https://www.wranglerforum.com/threads/eco-diesel-cold-idle.2409748/

 

[zouch]

and, just like that, it's gone.
turned out to be unrelated to any hardware (or fuel), but a software issue.

J**p is running like a champ again! thanks for all the helpful suggestions!

 

[unsavory]

and, just like that, it's gone.
turned out to be unrelated to any hardware (or fuel), but a software issue.

J**p is running like a champ again! thanks for all the helpful suggestions!

How do you know it was a software issue?

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