Pulling DFM fuses

voided3 · January 20, 2022

16 hours ago, xtrythis1 said:

Interesting topic, shame this doesn't work. I have a Range OBD2 DFM disabler but for the first 5 to 10 miles it still allows DFM to activate which is annoying and not great for a cold engine.. I just leave my trans in L7 (8 speed) and keeps it from kicking on until i hit the 10ish mile mark on a drive. Once i hit around 10 miles or so I can put it in D and runs as it should on all 8 cylinders all the time... until i turn the truck off again then have to start the whole process over again. UGH

That's a bummer. I would be so happy if there was a way to make it so "D" was the same as "L7" on the gear selector so I wouldn't have to toggle up every single time. I'd be even happier if cylinder deactivation never existed in internal combustion engines to begin with, but we have to set realistic goals, right?

Seriously, if the L84 and L87 had 1) regular non-collapsible lifters, 2) a single port fuel injector in addition to the GDI injectors to keep the valves clean, and 3) a friggin' belt tensioner, it would be such a good engine. I also realized I basically described an older LS engine. Hmm....

Deadstockpomp · January 26, 2022

I gave up and went pulsar. It was 100% worth it anyways. Just curious as to what these fuses do anyway. Sure it’s a complex electrical system. But I’m used to say if you pull your blower fan fuse your blower stops working. I think many would agree

M1ck3y · January 27, 2022

9 hours ago, Deadstockpomp said:

I gave up and went pulsar. It was 100% worth it anyways. Just curious as to what these fuses do anyway. Sure it’s a complex electrical system. But I’m used to say if you pull your blower fan fuse your blower stops working. I think many would agree

Yes, You can pull a fuse to disable the ecm (engine control module).

Edited January 27, 2022 by M1ck3y

xtrythis1 · January 27, 2022

9 hours ago, Deadstockpomp said:

I gave up and went pulsar. It was 100% worth it anyways. Just curious as to what these fuses do anyway. Sure it’s a complex electrical system. But I’m used to say if you pull your blower fan fuse your blower stops working. I think many would agree

Where is the best spot and price to get a pulsar? Also do you have to reprogram it every time you drive it to keep DFM off or does it save your setting and truck starts with it disabled every time..?

Thx

WeGone · January 27, 2022

1 minute ago, xtrythis1 said:

Where is the best spot and price to get a pulsar? Also do you have to reprogram it every time you drive it to keep DFM off or does it save your setting and truck starts with it disabled every time..?

Thx

Got mine from Diablosport $488 Once programed saves settings.

M1ck3y · January 28, 2022

20 hours ago, xtrythis1 said:

Where is the best spot and price to get a pulsar? Also do you have to reprogram it every time you drive it to keep DFM off or does it save your setting and truck starts with it disabled every time..?

Thx

It's inline, you plug it in and leave it there; you're not reprogramming anything. Pulsar intercepts instructions from the computer and alters it to achieve the desired response.

https://www.rangetechnology.com/products/pulsar_lt/parts/22451

https://documents.rangetechnology.com/pulsar_lt_manual.pdf

Edited January 28, 2022 by M1ck3y

thekcwolf · January 31, 2022

This is why I love these forums. here you have a group of folks that are all trying to decipher a circumstance with the sole reason of finding out much desired info for the greater good ! well done.

I'm VERY curious to know how many "Valve Lifter Failures" there has been, in engines that have the Pulsar units installed. Is it still happening?

A bit of background... My (potentially mine), '21 AT4, with, get this, a build date of 2/21... ***YIKES*** is supposed to be at the dealer by next week. It's a 5.3 with DFM and Auto Stop. Other than chip shortage issues, No idea why it has been sitting so long.

voided3 · January 31, 2022

4 hours ago, thekcwolf said:

This is why I love these forums. here you have a group of folks that are all trying to decipher a circumstance with the sole reason of finding out much desired info for the greater good ! well done.

I'm VERY curious to know how many "Valve Lifter Failures" there has been, in engines that have the Pulsar units installed. Is it still happening?

A bit of background... My (potentially mine), '21 AT4, with, get this, a build date of 2/21... ***YIKES*** is supposed to be at the dealer by next week. It's a 5.3 with DFM and Auto Stop. Other than chip shortage issues, No idea why it has been sitting so long.

I'm guessing this could be one reason: https://gmauthority.com/blog/2021/12/gm-releases-valve-lifter-service-update-for-v8-engines/

I would ask if they did the repair on that particular truck or not. I personally would not accept delivery of it until they have.

M1ck3y · February 1, 2022

4 hours ago, voided3 said:

I'm guessing this could be one reason: https://gmauthority.com/blog/2021/12/gm-releases-valve-lifter-service-update-for-v8-engines/

I would ask if they did the repair on that particular truck or not. I personally would not accept delivery of it until they have.

Problem is, that doesn't work when trucks/vehicles are in high demand.

Edited February 1, 2022 by M1ck3y

thekcwolf · February 1, 2022

11 hours ago, M1ck3y said:

Problem is, that doesn't work when trucks/vehicles are in high demand.

The high demand and the fact that there is no "market adjustment" on the vehicle I am waiting for, makes me want sit tight on it. I've seen other MUCH LESS equipped AT4s on the Build and Price/ Dealer Locator pages, listed near or above what this guy quoted me. That "build date", tho... 2/21... It's 2/22 now !!

RedLt4 · February 7, 2022

Reviewing another article “It turns out the changes are entirely electrical. The ECM is being swapped while all of the hardware components of AFM/DFM will still be present inside the engines.” Wonder what ECM they are using for this change?

20SierraL8T24 · February 8, 2022

On 1/31/2022 at 2:27 PM, thekcwolf said:

This is why I love these forums. here you have a group of folks that are all trying to decipher a circumstance with the sole reason of finding out much desired info for the greater good ! well done.

I'm VERY curious to know how many "Valve Lifter Failures" there has been, in engines that have the Pulsar units installed. Is it still happening?

A bit of background... My (potentially mine), '21 AT4, with, get this, a build date of 2/21... ***YIKES*** is supposed to be at the dealer by next week. It's a 5.3 with DFM and Auto Stop. Other than chip shortage issues, No idea why it has been sitting so long.

Your truck will have a reissued title and it'll be a 22.

thekcwolf · February 9, 2022

17 hours ago, 20Denali21 said:

Your truck will have a reissued title and it'll be a 22.

I'm more "concerned" about the fact, that this thing has been sitting around somewhere since February/March of last year and will STILL have these major engine problems !!

Edited February 9, 2022 by thekcwolf
Added content

20SierraL8T24 · February 10, 2022

13 hours ago, thekcwolf said:

I'm more "concerned" about the fact, that this thing has been sitting around somewhere since February/March of last year and will STILL have these major engine problems !!

Dealers have been instructed to replace the lifters on affected vehicles before they can sell them. I guarantee you thats why all these trucks have been sitting. Not waiting on chips, they're waiting on lifter stock to hit the dealers.

thekcwolf · February 10, 2022

9 hours ago, 20Denali21 said:

Dealers have been instructed to replace the lifters on affected vehicles before they can sell them. I guarantee you thats why all these trucks have been sitting. Not waiting on chips, they're waiting on lifter stock to hit the dealers.

Yes, there's a TSB out there. According to a request from "[email protected]", this vehicle was in an intermediate delivery status in Ft. Wayne. I hope you're right and I'm also hoping the dealer has something that tells me the work was performed, because that would ease my concerns.