Recall 37A mileage change - An unexpected surprise!

[Gary1243]

I recently took My 2021 1500 Laramie in for recall 37A service. This is the one for possible engine turn off while driving. Just a software update.
The day after the update I drove a 120 mile round trip route on interstate 5 from Salem, Or to Eugene, which I have done hundreds of times.
My mpg’s according to the trip computer (I use this number just for consistency not debating whether it is accurate or not) usually range from
18-21 depending on windage And my speed. It is remarkably consistent and predictable. The last several trips have registered an even 22. It is pretty obvious by viewing the gas gauge as well, there has been a noticeable decrease in fuel consumption.

Based on recall information I am guessing the recall leans out the fuel mixture a tad. Just curious what others have experienced and whether it might lead to a performance decrease when towing a trailer. This was quite a pleasant surprise.

Thanks, Gary

 

[HSKR R/T]

I recently took My 2021 1500 Laramie in for recall 37A service. This is the one for possible engine turn off while driving. Just a software update.
The day after the update I drove a 120 mile round trip route on interstate 5 from Salem, Or to Eugene, which I have done hundreds of times.
My mpg’s according to the trip computer (I use this number just for consistency not debating whether it is accurate or not) usually range from
18-21 depending on windage And my speed. It is remarkably consistent and predictable. The last several trips have registered an even 22. It is pretty obvious by viewing the gas gauge as well, there has been a noticeable decrease in fuel consumption.

Based on recall information I am guessing the recall leans out the fuel mixture a tad. Just curious what others have experienced and whether it might lead to a performance decrease when towing a trailer. This was quite a pleasant surprise.

Thanks, Gary

I doubt they are changing target A/F ratio while driving. It's going to be 14.7:1 while in closed loop operation. They could have adjusted injector duty cycle, or timing though.

 

[Toyzillgod]

I bought my 21 Laramie with a build date of 9-20 used 3 weeks ago. How can I tell if this recall has been performed or not?

 

[Runagun]

I recently took My 2021 1500 Laramie in for recall 37A service. This is the one for possible engine turn off while driving. Just a software update.
The day after the update I drove a 120 mile round trip route on interstate 5 from Salem, Or to Eugene, which I have done hundreds of times.
My mpg’s according to the trip computer (I use this number just for consistency not debating whether it is accurate or not) usually range from
18-21 depending on windage And my speed. It is remarkably consistent and predictable. The last several trips have registered an even 22. It is pretty obvious by viewing the gas gauge as well, there has been a noticeable decrease in fuel consumption.

Based on recall information I am guessing the recall leans out the fuel mixture a tad. Just curious what others have experienced and whether it might lead to a performance decrease when towing a trailer. This was quite a pleasant surprise.

Thanks, Gary

Noticed the same thing. Eco mode is enabling a lot more.

 

[FLiPMaRC]

https://static.nhtsa.gov/odi/rcl/2023/RCMN-23V265-2068.pdf

I guess this doesn't pertain to me since I don't have have eTorque.

 

[mikeru82]

I recently took My 2021 1500 Laramie in for recall 37A service. This is the one for possible engine turn off while driving. Just a software update.
The day after the update I drove a 120 mile round trip route on interstate 5 from Salem, Or to Eugene, which I have done hundreds of times.
My mpg’s according to the trip computer (I use this number just for consistency not debating whether it is accurate or not) usually range from
18-21 depending on windage And my speed. It is remarkably consistent and predictable. The last several trips have registered an even 22. It is pretty obvious by viewing the gas gauge as well, there has been a noticeable decrease in fuel consumption.

Based on recall information I am guessing the recall leans out the fuel mixture a tad. Just curious what others have experienced and whether it might lead to a performance decrease when towing a trailer. This was quite a pleasant surprise.

Thanks, Gary

Do you know what your hand calculated mileage before the recall fix was, and if so have you hand calculated it after the update for a truer comparison? I'm just thinking since the recall was software related, and the trip computer runs on said software, the update may have affected the calculated fuel economy in some way. If your fuel economy really did improve, but since I test embedded software for a living I can't say I fully trust it because I know how buggy it can be LOL.

 

[6of36]

I recently took My 2021 1500 Laramie in for recall 37A service. This is the one for possible engine turn off while driving. Just a software update.
The day after the update I drove a 120 mile round trip route on interstate 5 from Salem, Or to Eugene, which I have done hundreds of times.
My mpg’s according to the trip computer (I use this number just for consistency not debating whether it is accurate or not) usually range from
18-21 depending on windage And my speed. It is remarkably consistent and predictable. The last several trips have registered an even 22. It is pretty obvious by viewing the gas gauge as well, there has been a noticeable decrease in fuel consumption.

Based on recall information I am guessing the recall leans out the fuel mixture a tad. Just curious what others have experienced and whether it might lead to a performance decrease when towing a trailer. This was quite a pleasant surprise.

Thanks, Gary

My brother had the recall performed before it was publicized. He had it in for something else, and the dealer just got the info, so performed it before the mailings went out. He had been complaining about the truck downshifting on slight declines, since he got it. He said the recall cured that, and gained 2-3 MPG.

 

[Gary1243]

Do you know what your hand calculated mileage before the recall fix was, and if so have you hand calculated it after the update for a truer comparison? I'm just thinking since the recall was software related, and the trip computer runs on said software, the update may have affected the calculated fuel economy in some way. If your fuel economy really did improve, but since I test embedded software for a living I can't say I fully trust it because I know how buggy it can be LOL.

I did after I bought it but I gave up on that soon there afterwards as here in Oregon it was both illegal to pump your own gas and top off your tank. You could be off by a couple gallons of gas at times depending on the pump sensitivity and the attendant. Just recently they passed a law that we will be able to pump our own gas soon. Then I can be sure that I am consistent in the fill process which will allow me to be pretty accurate on hand calculations. From watching the gas gauge there is no doubt there has been an improvement, but it is anecdotal at best.

 

[HSKR R/T]

I did after I bought it but I gave up on that soon there afterwards as here in Oregon it was both illegal to pump your own gas and top off your tank. You could be off by a couple gallons of gas at times depending on the pump sensitivity and the attendant. Just recently they passed a law that we will be able to pump our own gas soon. Then I can be sure that I am consistent in the fill process which will allow me to be pretty accurate on hand calculations. From watching the gas gauge there is no doubt there has been an improvement, but it is anecdotal at best.

You don't want to "top off" your tank or you risk getting fuel in the vent tube to evap canister and causing check engine lights.

 

[FastBlackRam]

You don't want to "top off" your tank or you risk getting fuel in the vent tube to evap canister and causing check engine lights.

It's great to see posts like this. I have wondered why you are not supposed to top off your gas tank (I never do because I listened to that advice blindly), but now I know the real reason. Thanks!