Engine start stop

[JeepnJam]

No Start / Stop button to push - instead you get the Loud / Quiet button!!!

 

[Shortcut]

Also get the Variable Displacement function which is the 5.7 Hemi killer.

 

[Guest23421]

Also get the Variable Displacement function which is the 5.7 Hemi killer.

Thats why I'm real curious if you fine a tuner to get rid of this, because I don't like that engine feature either lol

 

[Eugene Rubicon 392]

They did not put the start / stop technology on the 392, and we were so relieved because we hated it on other rubicon that we traded in.

My 392 Rubicon does not stop and start itself at lights etc. I'm very pleased that it doesn't have this. My other vehicle DOES have it, but you can disable it and the choice stays even after you shut off the vehicle. If you DO select stop/start the choice remains until you then reject it. It HOLDS whatever selection you make until the next time you change your mind. I always leave it off.

 

[Eugene Rubicon 392]

Also get the Variable Displacement function which is the 5.7 Hemi killer.

Can you elaborate on what is meant by 5.7 Hemi killer ?

 

[Ngcannotwait]

My 392 Rubicon does not stop and start itself at lights etc. I'm very pleased that it doesn't have this. My other vehicle DOES have it, but you can disable it and the choice stays even after you shut off the vehicle. If you DO select stop/start the choice remains until you then reject it. It HOLDS whatever selection you make until the next time you change your mind. I always leave it off.

SO LOVE that they did NOT put the stop/start on the 392

 

[Ngcannotwait]

Can you elaborate on what is meant by 5.7 Hemi killer ?

The stop/start feature that is on all vehicles now - EXCEPT… it seems… the 392

 

[cburgess33]

agree not there with the 392 and thankful for that. WRT MDS is there a setting to see when the truck drops into 4cylinder mode ? And I mean a setting on the dash to indicate ECO mode or something ?

 

[Shortcut]

agree not there with the 392 and thankful for that. WRT MDS is there a setting to see when the truck drops into 4cylinder mode ? And I mean a setting on the dash to indicate ECO mode or something ?

I haven't found one yet but I'm hoping Livernois Motor Sports PCM Unlock and 392 tune has the ability to disable that function. Just started working with a shop that does Livernois Tune ups whith PCM Unlock and the Jeep 392 Livernois Tuner. I found out it can program the PCM with many of the same functions as the Tazer Mini and... can also increase the speed governor limit without throwing a code.

 

[YukonCornelius]

My issue with the cylinder deactivation as fuel savings as they extra wear (or less wear on the non-running) on the 4 cylinders that never deactivate. They should actually fire in an alternating bank pattern, using all 8 cylinders 4 at a time, but I don't believe the HEMI does. I hope someone out there can correct me...

 

[cburgess33]

My issue with the cylinder deactivation as fuel savings as they extra wear (or less wear on the non-running) on the 4 cylinders that never deactivate. They should actually fire in an alternating bank pattern, using all 8 cylinders 4 at a time, but I don't believe the HEMI does. I hope someone out there can correct me...

I agree and u want to know when it’s engaged or not tbh or at least I do

 

[Jeepstin392]

My issue with the cylinder deactivation as fuel savings as they extra wear (or less wear on the non-running) on the 4 cylinders that never deactivate. They should actually fire in an alternating bank pattern, using all 8 cylinders 4 at a time, but I don't believe the HEMI does. I hope someone out there can correct me...

What Is Hemi MDS?

We explain how Chrysler Hemi MDS cylinder deactivation works, what goes wrong, and how to fix it when it breaks.

www.motortrend.com

 

[YukonCornelius]

Yup… I was correct in that the HEMI shuts down the same 4 cylinders. Per Motortrend:
“During MDS activation, cylinders 1, 4, 6, and 7 are shut down in order, with one cylinder being deactivated every 180 degrees of crankshaft rotation. Part of the cleverness of MDS is that a change to 4-cylinder mode—called "Eco" mode as displayed on the instrument cluster—happens without any apparent loss of power.’

so the same 4 cylinders run and fire 100% of the time.

 

[Jeepstin392]

Yup… I was correct in that the HEMI shuts down the same 4 cylinders. Per Motortrend:
“During MDS activation, cylinders 1, 4, 6, and 7 are shut down in order, with one cylinder being deactivated every 180 degrees of crankshaft rotation. Part of the cleverness of MDS is that a change to 4-cylinder mode—called "Eco" mode as displayed on the instrument cluster—happens without any apparent loss of power.’

so 4 cylinders run and fire 100% of the time.

I’m interested in a delete. The drone is not ideal when it drifts to 4-cyl, and, I just don’t like it.

 

[Idaho392]

I’m interested in a delete. The drone is not ideal when it drifts to 4-cyl, and, I just don’t like it.

The Livernois tune eliminates the 4-cylinder deactivation completely.

 

[cburgess33]

apparently there is a way to get notification if its in 4cylinder mode :
FUEL SAVER TECHNOLOGY 6.4L This feature offers improved fuel economy by shutting off four of the engine's eight cylinders during light load and operation. The system is automatic with no driver inputs. It is not available in 4WD Low. There is also a four cylinder indicator in the instrument cluster to indicate when this feature is active. NOTE: This system may take some time to return to full functionality after a battery disconnect.

I guess I just need to find the setting - Ill tinker around with this later

 

[hydro392]

As far as I know, vehicles using the 6.4/392 HEMI engine do not employ the start stop technology. However they do use a Multiple Displacement System (MDS) that supposedly can be turned off. Also, all 6.4/392 HEMI engines use Variable Cam Timing (VCT)

Do we know if MDS can be turned off without tuning?

 

[Idaho392]

Do we know if MDS can be turned off without tuning?

As of right now, the Livernois tune is the only way to disable it. I contacted the Tazer people a few months ago, to see if they could add it, but they claimed they don’t have access to that control.

 

[Jeepstin392]

As of right now, the Livernois tune is the only way to disable it. I contacted the Tazer people a few months ago, to see if they could add it, but they claimed they don’t have access to that control.

They likely don’t want any flack from the EPA.

 

[Jeepstin392]

apparently there is a way to get notification if its in 4cylinder mode :
FUEL SAVER TECHNOLOGY 6.4L This feature offers improved fuel economy by shutting off four of the engine's eight cylinders during light load and operation. The system is automatic with no driver inputs. It is not available in 4WD Low. There is also a four cylinder indicator in the instrument cluster to indicate when this feature is active. NOTE: This system may take some time to return to full functionality after a battery disconnect.

I guess I just need to find the setting - Ill tinker around with this later

It’s automated. There’s no setting to turn it off or on. It’s also active when Off Road+ is engaged.