DFM L9 vs pulsar lt

matt grz · October 9, 2022

Man has my DFM gotten bad. Brought it to the dealer and they say it’s normal but it drives me nuts. Transmission studdering, engine feels like it’s struggling, just garbage.

I have a 2020 elevation with the 5.3 and 10 speed just under 17,000 miles. Putting it in L9 seems to make it so much better.

Is there a difference between running in L9 mode and installing a pulsar LT strictly for the DFM disable feature? Is there any issues with running in L9 or with the pulsar LT full time all of the time? Are there any issues with towing in L9 or with the pulsar LT? Is it ok to run on the highway at high speed in L9 or with the pulsar LT?

it’s very depressing that I have to just accept having my $60,000 truck run like a beater POS

TonyBoss · October 9, 2022

Driving in L9 won’t hurt anything except your fuel mileage-it does disable DFM. The Pulsar will disable DFM as well but you will have all 10 speeds; you can also shut off auto stop, adjust throttle response and calibrate for bigger tire size. I have it on my Trailboss and highly recommend the Pulsar.

Josh42089 · October 20, 2022

Another option worth looking into is the range afm/dfm disabler. I have that and it strictly disabled the afm/dfm. Quite a bit cheaper than the pulsar but uses the obd2 port. Would have to see if it works for yours as mine is the 5.3 with the 6 speed. So much better driving without that.

TonyBoss · October 20, 2022

Range does not work on the 10 speed- you have to get the Pulsar.

voided3 · October 22, 2022

On 10/8/2022 at 8:02 PM, Matt Grz said:

Are there any issues with towing in L9 or with the pulsar LT? Is it ok to run on the highway at high speed in L9 or with the pulsar LT?

Our '21 has the 5.3 and the 8-speed and I always drive in L7 for normal driving to disable DFM. Our engine turns about 1900 RPM at 65 MPH in 7th gear (3.23 axle ratio) and it seems perfectly happy there. Running that speed in 7th with 89 octane gas and stock Michelin all season tires at 38 PSI, though with the air dam removed, I can average up to 23 MPG on a longer highway trip on flat-ish terrain, so no real fuel economy loss in that scenario, either.

When towing, I use L6 on the highway as that is the 1:1 gear in our transmission (your 1:1 gear is 7th gear in the 10-speed). Since we tow a camper with a fair amount of wind resistance, holding the engine at roughly 2000-2100 RPM at highway speed (65 MPH or less) is ideal to avoid lugging the engine or excessive hunting for gears. On extended up hill grades on the highway, I shift down one gear (L5) so it's closer to 2900 RPM. We get between 11-13 MPG towing our roughly 3700 lbs. 19 ft. camper on 89 octane. Don't forget to engage tow/haul mode, too.

DHBWA · November 30, 2022

I highly recommend the Pulsar. The ability to increase throttle sensitivity is worth the additional coin. The DFM and auto stop delete works as they say. I’ve only ran it for a week but I am sold!!!