Jump to content

Auto stop/start quandary

Acpantera
 Share

Recommended Posts

Acpantera Enthusiast

Acpantera

Posted
Posted

I know I'm probably one of the few folks that doesn't mind the feature on the new vehicles, and I know a lot of parameters are taken into consideration for it to operate. The only issue I am having is that when the engine does shut off at a red light, the engine only stays off for roughly 30 seconds, and most traffic lights are red for about 60 seconds, it would seem the fuel savings could be increased by staying off for the full duration of the light. Has anyone found a way to extend the "off time"? So far I have operated the truck in ambient temps between 60 to 90 degrees and tried turning off the hvac and other accessories, still haven't been able to extend the off time.

Z45 Senior Enthusiast

Z45

Posted
Posted

Its controlled by the ecm and there is no way to change the parameters;  Have to live with the way it is.  PS, I turn off every start.

  • Like 1
  • Thanks 1
Minnvmax Enthusiast

Minnvmax

Posted
Posted (edited)

Say what?! My 2019 has never turned back on by itself. I have to lift the break or tap the gas. I too turn it off every time I start.  Have I really had this truck that long and not sat with it off long enough for this even to happen?

Edited by Minnvmax
  • Like 1
bdallas Enthusiast

bdallas

Posted
Posted (edited)

My experience has been that if I turn the A/C off, the engine stays off until I take my foot off of the brake. That's true for as long as the red light lasts. I'm sure if I were to sit there too long, the engine would kick back on.

 

...but if my A/C is on, it kicks back on in 30 seconds or so.

Edited by bdallas
add info
  • Like 1
redwngr Senior Enthusiast

redwngr

Posted
Posted

Time limit for the stop portion of auto stop/start is 2 minutes.

 

If it's starting sooner it's one of the other reasons.

 

Autostart Criteria
 

Driver Enabled Conditions that will engage Autostart:
• Driver removes pressure from the brake or depresses the accelerator pedal while the vehicle is in the forward Drive gear System Enabled Conditions that will engage Autostart
 

Note: If one or more of the following conditions occur, the system will force the engine to restart.
• Economy mode turned OFF
• Brake booster vacuum is less than 40 kPa (6 PSI)
• HVAC inside air temperature changes than 3°C (5°F) (with HVAC Automatic)
• A/C compressor request from HVAC (A/C or Defrost modes)
• Battery voltage less than 11 V,
• Battery state of charge is less than 73% (changes with state of health)
• Driver door status changes to open and driver seat belt status changes to unbuckled (not applicable to vehicles in North America)
• Hood switch status changes to open
• Autostop time exceeded 2 min
 

If the crank time exceeds 2 s, a manual ignition switch restart will be necessary. 

 

 

I believe 'Economy mode' refers to one of the modes for the charging system

  • Like 2
Acpantera Enthusiast

Acpantera

Posted
  • Author
Posted
3 minutes ago, redwngr said:

Time limit for the stop portion of auto stop/start is 2 minutes.

 

If it's starting sooner it's one of the other reasons.

 

Autostart Criteria
 

Driver Enabled Conditions that will engage Autostart:
• Driver removes pressure from the brake or depresses the accelerator pedal while the vehicle is in the forward Drive gear System Enabled Conditions that will engage Autostart
 

Note: If one or more of the following conditions occur, the system will force the engine to restart.
• Economy mode turned OFF
• Brake booster vacuum is less than 40 kPa (6 PSI)
• HVAC inside air temperature changes than 3°C (5°F) (with HVAC Automatic)
• A/C compressor request from HVAC (A/C or Defrost modes)
• Battery voltage less than 11 V,
• Battery state of charge is less than 73% (changes with state of health)
• Driver door status changes to open and driver seat belt status changes to unbuckled (not applicable to vehicles in North America)
• Hood switch status changes to open
• Autostop time exceeded 2 min
 

If the crank time exceeds 2 s, a manual ignition switch restart will be necessary. 

 

 

I believe 'Economy mode' refers to one of the modes for the charging system

Thanks for the posting, out of all the stuff I read on the topic yours is the first I have seen that mentions the 2 minute max, maybe mine being the 2.7 has different requirements for the start stop. Perhaps I just haven't hit the just right conditions for the engine to stay off for more than 30 seconds. Also I do want to add that I too shut off the feature when I know I'm in an area where there is a lot of stop signs or when I'm maneuvering around where auto stop make no sense or is a nuisance. 

aseibel Senior Enthusiast

aseibel

Posted
Posted

My wife's 21 Acadia Denali does not have any option to turn it off. Most of the time it doesn't bother me as I don't drive in a lot of traffic with lights due to where we live. If it shuts off at a stoplight, it turns on quick enough not to be an inconvenience. It does turn back on after a certain time. Definitely using the AC keeps the engine on more.

 

The worst situation I endure is a 4-way stop where I have to wait for someone else to clear the intersection, I may be sitting still for 2 seconds but the engine shuts off in that time, then re-starts. Its teaching me to roll through the stop sign rather than hard-stop it.

redwngr Senior Enthusiast

redwngr

Posted
Posted
34 minutes ago, aseibel said:

My wife's 21 Acadia Denali does not have any option to turn it off. Most of the time it doesn't bother me as I don't drive in a lot of traffic with lights due to where we live. If it shuts off at a stoplight, it turns on quick enough not to be an inconvenience. It does turn back on after a certain time. Definitely using the AC keeps the engine on more.

 

The worst situation I endure is a 4-way stop where I have to wait for someone else to clear the intersection, I may be sitting still for 2 seconds but the engine shuts off in that time, then re-starts. Its teaching me to roll through the stop sign rather than hard-stop it.

They will only do one stop/start cycle per stop.

 

Lift foot off brake just enough to get a restart and it will stay running for however long to continue to be stopped.

 

Our 2020 Acadia Denali has the stop/start disable switch on the console just ahead of the cup holders.  

 

2021 Acadia OM -- Auto Stop Disable Switch  Graphic

image.png.7b23f486cfd27f3cdd4c92a1d7e93503.png

 

 

  • Like 1
aseibel Senior Enthusiast

aseibel

Posted
Posted
1 hour ago, redwngr said:

Our 2020 Acadia Denali has the stop/start disable switch on the console just ahead of the cup holders.  

 

Well holy &^%$, there it is. I just went out and looked. We do have it. I swore I read somewhere that it didn't exist and I never bothered to look.

I'm pretty used to it shutting off now, and yes, just lifting the foot 90% off the brake it will fire up. Now I don't know what I'll do when driving her vehicle around. My truck is a 15 so I don't have to worry about it at all.

  • Like 1
Acpantera Enthusiast

Acpantera

Posted
  • Author
Posted

Well, Did some test running late yesterday. Engine and tranny up to operating temps, hvac set and maintaining the same outside temp, longest the engine would stay off was about 40 seconds. 

Turned the hvac completely off and the engine would stay off for 2 minutes. All normal I guess. Thanks for helping me through it.

  • Like 1
Wiggums Senior Enthusiast

Wiggums

Posted
Posted

Keeping your foot firmly on the brakes makes a difference. If you lighten it, the truck thinks you're just slowing down in traffic. I also think having accessories being charged shortens the off time.

Acpantera Enthusiast

Acpantera

Posted
  • Author
Posted
33 minutes ago, Wiggums said:

Keeping your foot firmly on the brakes makes a difference. If you lighten it, the truck thinks you're just slowing down in traffic. I also think having accessories being charged shortens the off time.

That one I figured out one the first day.

My last car had "auto hold", one feature I kinda miss. Come to a complete stop and you could take your foot off the brake and it stayed put til you hit the gas.

 

Toolmandbq New Member

Toolmandbq

Posted
Posted

I got sick of hitting the button every time.  Bought the auto stop start eliminator from 4Dtech.  Works perfect every time.  Took about 30 min to install.  They have an excellent step by step video on how to install it.  After driving around with it for 2 months I found no change in my mileage. It just eliminates the annoying restart after every stop.  

  • Like 1

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing

  • Latest Articles

  • Posts

    • Chuck FB
      Tire psi

      By Chuck FB · Posted

      I will admit I haven't experimented much with pressure drops beyond the numbers I put in and part of that is that the numbers I used are fairly low and then found out it would trigger regardless at that 35 psi. Having said that I had tried before had changed the placard pressures and being that I have a 1 ton set to 80 on the placard for the rear I believe it triggered close to 60, the front I don't recall now for sure but thought maybe it could get close to 45 from that factory 60 placard pressure. So I never did figure out if it was a number of psi from placard pressure to the alarm or a percentage of the total placard number as some figured it was like a 25% drop from placard pressure would trigger it. So as to try and answer your question, I believe I set the placard pressure on the front to 47 or so and while I run the front tires at 40, they have dipped below that some if its colder and I haven't put "winter air" in yet and never once have had the front alarm go off. I would say that the answer your looking for is no, that if you set your placard pressure to 45, you have a certain amount of room to drop below that pressure before the alarm will go off.    The pressures you decide to run in your truck, that ends up being what makes sense to you based on what your carrying in your truck or if towing, then have to bump them back up to something that will carry the load in the rear and the fronts typically left at the same pressure. It all comes down to that chart I put the link to and using an accurate roadside scale to be your guide, both unloaded and then loaded to know your minimum safe pressures.    I just wish GM would allow a person to change the readings for the tire pressures to the English system of pounds as I have to look at that goofy metric reading that will never ever jive in my head and will go over and change it just to figure out what they are if need be and then change it back. 
    • TrueBlue
      No Software Updates - Old Build

      By TrueBlue · Posted

      That part I understand, that the dealer can do it. But I'm not understanding why updates that were available to the truck since it left the factory, or the dealership originally, would not still be available to it without dealer intervention.   I'm thinking along the lines of recalls. They stay available until they are completed. Why not updates as well, especially since some of those can be safety related also?
    • jgaudet99
      Tire psi

      By jgaudet99 · Posted

      That's good to know, but I don't think I'll even be running them under 45 in the rear  unless it's on the sand or something but will only be for a short distance anyways!    I didn't read all the instructions in the booklet yet, but do you know let's say I set the rear psi on the placard to 45, will the warning light come on soon as it drops under 45 or is there a percentage it has to drop from the set value before the warning light is triggered?
    • newdude
      Would this CV Shaft be bad?

      By newdude · Posted

      That's bad.  Like, its probably destroying the stub axle the CV slides into.   Do you have a proper lift installed with differential lowering brackets?  Did you install AT4/Trail Boss factory CV axles?  
    • PunchT37
      Would this CV Shaft be bad?

      By PunchT37 · Posted

      Hot? New Jersey? Today? I was working on my old 2000 Silverado 1500 today. Believe me, it was boiling hot today. As it has been.

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...