Range D.F.M. disabler

Diamond817 · July 30, 2021

I have on for sale. $150 shipped.

Ratchetarms · March 7, 2022

I just ordered and received a Range DFM disabler for my 2019 5.3. While the unit seemed to function ok, I wanted to share something it did that I did not like. I am by no means bad mouthing the company or product, but I believe that the fact it disables DFCO (deceleration fuel cut off), should be revealed on their website. This was a deal breaker for me. I drive over the continental divide twice a day. I plugged in the unit and headed up to the divide. Upon heading down the other side, I was constantly on my brakes, even on smaller hills and in 5th gear at 3000 RPM. I promptly unplugged it, and immediately began slowing down, even in 8th gear. I can,t imagine using this in the mountains with a trailer. I decided to send it back,as this was unacceptable to me. I also noticed deceleration mileage was around 40 to 50 mpg, instead of maxed out at 99 mpg. It actually felt like it was giving it a little bit of throttle.

I was curious if the Range Pulsar LT does this as well. I'm guessing it probably does. If anyone knows for sure, please comment.

dgstarr63 · March 7, 2022

I had the Range on my 2015 5.3, 6 speed, AFM, worked great. I now have a 2021 5.3, 8 speed with DFM. I sent the Range to the manufacturer and they modified it for the new truck. It also works great. I have not experienced the rough shifts since the dealer replaced the valve body. I don't think the Range effects the shifts. I think the mileage is a little lower, but there is nothing else negative that I have noticed.

Ratchetarms · March 12, 2022

Do you still have fuel cut off when decelerating? That is my complaint. It had absolutely no engine braking. Even at 3000 rpm. I sent it back. I only ran it 15 miles. No strange shifting and it did keep the dfm from kicking in?

GSC52 · March 16, 2022

I plugged mine in for a few weeks after getting it. Worked as should, but after unplugging, the auto/start feature is still disabled. Has anyone ever seen that behavior? 2019 5.3L with 8 speed.

brewtus · March 16, 2022

Have you confirmed with RANGE that is how the Pulsar is supposed to function - no engine braking?

Ratchetarms · March 16, 2022

31 minutes ago, brewtus said:

Have you confirmed with RANGE that is how the Pulsar is supposed to function - no engine braking?

No, I didn't. I bought it off of Amazon and just returned. I thought about contacting them, but choose just to return it.

mwlewis558 · March 24, 2022

On 3/16/2022 at 3:04 PM, GSC52 said:

I plugged mine in for a few weeks after getting it. Worked as should, but after unplugging, the auto/start feature is still disabled. Has anyone ever seen that behavior? 2019 5.3L with 8 speed.

I haven't had this issue but I have noticed if I leave the unit plugged in and after a few trips I'll come to a stop and the auto start/stop will be activated. I just unplug the unit and plug it back in and its fixed.

xtrythis1 · April 11, 2022

I got a Range DFM disabler for my 2020 5.3L 8 speed. I noticed when i first start the truck it always chooses to use DFM for the first few miles including fuel cut off (99mpg) while on decel and then magically turns it off so it engages at random and i have no control over it. Does not do auto start/stop though.. Does anyone else have this problem? Do y'all unplug it safter every drive then plug it in when you drive again? After about 5 to 10 min it'll kick in and start working. I think the worst time to use DFM is when the engine is cold and that's why it drives me nuts and i end up putting it in L7 until the engine is up to temp then go into D...