4th Gen 6.4 Hemi High Idle Funtion?

[Erikk]

There seems to be a general agreement that prolonged idle of the Hemi leads to lifter/cam problems. The 13+ 6.4 Hemi in the 25-5500 trucks seem to have a high idle function like the 6.7 CTD.

Has anyone figured out if it can be activated using Alfa? I emailed Alexey (Alfaobd Designer) twice about it but haven’t had any response.

 

[Erikk]

Maybe dealer could program it in if Alfaobd can’t do it? Anyone have any idea? It would be a great function for winching too.

 

[olyelr]

I can operate it with the Tazer. Pressing the right arrow and cruise on/off button turns the idle up. I think it jumps it up to 2000-2500 RPM.

 

[Erikk]

I can operate it with the Tazer. Pressing the right arrow and cruise on/off button turns the idle up. I think it jumps it up to 2000-2500 RPM.

Tazer plugged in all the time?
What is the lowest high idle rpm you can set?

 

[Erikk]

Tazer plugged in all the time?
What is the lowest high idle rpm you can set?

Just read up on Tazer. You do need to have it plugged in.
On the ctd you get anywhere from 1k to 2k high idle rpm set with cruise buttons. I think all a 6.4 would need for better idle oil psi would be 900 to 1k idle up for when you need to sit in truck and run a/c or heat. Was hoping there was a way to just activate it on a regular 2500 pickup like you can a c&c truck.

I looked in my Alfaobd and found where you can change rpm so maybe just permanently bumping up rpm would work, maybe to 850 or 900.

 

[olyelr]

Pressing the right arrow and cruise on/off button turns the idle up.

Just read up on Tazer. You do need to have it plugged in.
On the ctd you get anywhere from 1k to 2k high idle rpm set with cruise buttons. I think all a 6.4 would need for better idle oil psi would be 900 to 1k idle up for when you need to sit in truck and run a/c or heat. Was hoping there was a way to just activate it on a regular 2500 pickup like you can a c&c truck.

I looked in my Alfaobd and found where you can change rpm so maybe just permanently bumping up rpm would work, maybe to 850 or 900.

Why do you want the idle up a few hundred more rpm? You think that might be the magical number to prevent your lifters from failing?

 

[Erikk]

Why do you want the idle up a few hundred more rpm? You think that might be the magical number to prevent your lifters from failing?

Just a 200 rpm increase bumps oil pressure up by 20 psi.
There seems to be a hunch within FCA that the oil pressure at idle may be starving back cam and lifters of oil and that’s why emergency response type Hemi’s are having many more cam/lifter failures than the general public Hemi’s. I have noticed on mine that it’s 35psi at hot idle, but at 1k it’s 56psi. There is also the thought that had they set idle higher there may not be as much of a problem with cam/lifter failures. Seems to be a plausible theory so Im researching options.
I just came over to the 6.4 from a 6.7 ctd. One of the reasons for changing power plants was needing to idle a lot on occasion. (Truck office)

 

[olyelr]

Just a 200 rpm increase bumps oil pressure up by 20 psi.
There seems to be a hunch within FCA that the oil pressure at idle may be starving back cam and lifters of oil and that’s why emergency response type Hemi’s are having many more cam/lifter failures than the general public Hemi’s. I have noticed on mine that it’s 35psi at hot idle, but at 1k it’s 56psi. There is also the thought that had they set idle higher there may not be as much of a problem with cam/lifter failures. Seems to be a plausible theory so Im researching options.
I just came over to the 6.4 from a 6.7 ctd. One of the reasons for changing power plants was needing to idle a lot on occasion. (Truck office)

Totally makes sense.

How are you handling the motor change-over?

 

[Erikk]

Totally makes sense.

How are you handling the motor change-over?

Im mostly glad I did the change but it will take some getting used to. The simplicity of the gas engine over the modern diesel is refreshing. If I could have economically and legally converted my ctd to a pre-emissions truck I would probably have kept it. Truthfully I had no business (economically) owning the ctd with as little towing as I do, I just never owned a gas truck that I thought could handle truck things like a diesel. This 6.4 converted me. It’s one of the best truck decisions I’ve made, and have no regrets.

 

[olyelr]

Im mostly glad I did the change but it will take some getting used to. The simplicity of the gas engine over the modern diesel is refreshing. If I could have economically and legally converted my ctd to a pre-emissions truck I would probably have kept it. Truthfully I had no business (economically) owning the ctd with as little towing as I do, I just never owned a gas truck that I thought could handle truck things like a diesel. This 6.4 converted me. It’s one of the best truck decisions I’ve made, and have no regrets.

Well heck yea

 

[michael harpe]

pardon me for being a newb to the entire ram lineup, and I just got a 2018 power wagon, so im learning. my question is.. im a little confused on this thread.. are you saying there are cam/lifter lubrication issues when idling for extended periods with the 6.4L and we need to engage high idle? or will we be fine just using a regular idle? I used to drive OTR and am familiar with high idling for keeping the Cummins ISX going to run AC

 

[olyelr]

Your fine with the normal idle. However, when winching I could see using the high idle.

 

[IRSmart]

Your fine with the normal idle. However, when winching I could see using the high idle.

Exactly why I put the dual alternators on my build. I’ve seen what an electrical toll the winch can take on the system. Every little bit helps.

 

[michael harpe]

Maybe dealer could program it in if Alfaobd can’t do it? Anyone have any idea? It would be a great function for winching too.

when i used my winch, it increased the idle automatically.. does yours not do the same thing? I'm new the to PW so i have no base comparison.

 

[Erikk]

Mine is a regular 2500 not a PW so it doesn’t have a winch. I didn’t know the PW automatically raised the idle for winch use though. I just wanted to figure out how to raise the rpm for prolonged ac or heater use while using the truck as an office so the idle oil pressure would be higher.

 

[michael harpe]

Mine is a regular 2500 not a PW so it doesn’t have a winch. I didn’t know the PW automatically raised the idle for winch use though. I just wanted to figure out how to raise the rpm for prolonged ac or heater use while using the truck as an office so the idle oil pressure would be higher.

Ah I see


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[22hemi13]

I’m engine and perf section or search. There’s tons of info on this and this theory. To me it makes perfect sense. When I tune my wife’s 1500 5.7 I’m going to bump up the idle a tad. The oil psi at idle is low on all these trucks. Although you’d think if that really was the issue fca would do a recall and up the idle rpm. They have not so maybe it’s not the cause. But.....I’d rather be safe than sorry

 

[Fitz-0518]

Our 6.4 HD engines do have variable pressure oil pumps. Just a increase of 50 RPM at idle raises the oil pressure. I too suspect that the valve train failure in some of these vehicles is low oil pressure at idle. Our neighbor who is a line tech at our local dealer says they continue to average 1 police cruiser per month with cam failure. He says technical support tells them this is common with the Hemi emergency vehicles through out the country. FCA now just ships them a new engine as they can change out an engine in hours versus replacing the valve train. He says they see this failure at about 50-70k miles.

 

[Neumie]

Our 6.4 HD engines do have variable pressure oil pumps. Just a increase of 50 RPM at idle raises the oil pressure. I too suspect that the valve train failure in some of these vehicles is low oil pressure at idle. Our neighbor who is a line tech at our local dealer says they continue to average 1 police cruiser per month with cam failure. He says technical support tells them this is common with the Hemi emergency vehicles through out the country. FCA now just ships them a new engine as they can change out an engine in hours versus replacing the valve train. He says they see this failure at about 50-70k miles.

Can you ask your neighbor what the idle vs driving hours are? That would be the best comparison imo.

 

[Fitz-0518]

Can you ask your neighbor what the idle vs driving hours are? That would be the best comparison imo.

He says that the ones that are failing average 25%-35% idle time. He also added that we need to keep in mind these are 24/7 service vehicles that often are driven hard in hot weather. Their hours running are greater than the daily miles they put on. Fitz