Need Deleted L5P Advice

Brozat4 · January 30, 2021

Hello from a Canadian. My 2020 AT4 HD 3500 recently threw a check engine light, turns out it was heater #3 in my DEF tank. Two of my co workers have already had this issue months ago and now it's my turn. Dealership is saying 2 to 8 weeks for a new tank to come in. If it happened once its going to happen again next winter.

I am SERIOUSLY considering getting it deleted and tuned with an Optimized Factory tune. Could someone who has already done this and is willing to answer some questions please PM me? It would be greatly appreciate. There is a few things I'd like to know before I drop $8000.

Thanks in advance!

Edited January 31, 2021 by Brozat4
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jeetS · January 31, 2021

18 hours ago, Brozat4 said:

Hello from a Canadian. My 2020 AT4 HD 3500 recently threw a check engine light, turns out it was heater #3 in my DEF tank. Two of my co workers have already had this issue months ago and now it's my turn. Dealership is saying 2 to 8 weeks for a new tank to come in. If it happened once its going to happen again next winter.

I am SERIOUSLY considering getting it deleted and tuned with an Optimized Factory tune. Could someone who has already done this and is willing to answer some questions please PM me? It would be greatly appreciate. There is a few things I'd like to know before I drop $8000.

Thanks in advance!

Fellow Canadian here, my truck is on order so I don't have any input but want to stay informed... Good luck!

Colossus · January 31, 2021

Are you 100% certain that they can tune for deleted DPF/DEF?

Brozat4 · January 31, 2021

Absolutely, I know 2 guys with 2017 L5Ps done. I've asked them a few questions, however they pertain to features that 2020s have and they do not

07HD · February 1, 2021

Not sure about Canada but in the US its against federal law.

Brozat4 · February 1, 2021

Ya here in alberta it's hard to find a diesel that isn't deleted.

gSwift · February 7, 2021

On 1/30/2021 at 5:39 PM, Brozat4 said:

Hello from a Canadian. My 2020 AT4 HD 3500 recently threw a check engine light, turns out it was heater #3 in my DEF tank. Two of my co workers have already had this issue months ago and now it's my turn. Dealership is saying 2 to 8 weeks for a new tank to come in. If it happened once its going to happen again next winter.

I am SERIOUSLY considering getting it deleted and tuned with an Optimized Factory tune. Could someone who has already done this and is willing to answer some questions please PM me? It would be greatly appreciate. There is a few things I'd like to know before I drop $8000.

Thanks in advance!

I haven't researched it much, but I do remember seeing a guy on YouTube who deleted his 2020 Denali. I think it's been pretty reliable for him. I think it's DennyDiesel on YouTube

rblanch · April 9, 2021

You cannot buy a tuner you have to either have your ecm unlocked or purchase an unlocked ecm and purchase tunes for your unlocked ecm. usual cost for everything is around 6-7,000 dollars.

Brozat4 · April 11, 2021

On 4/9/2021 at 7:42 AM, rblanch said:

You cannot buy a tuner you have to either have your ecm unlocked or purchase an unlocked ecm and purchase tunes for your unlocked ecm. usual cost for everything is around 6-7,000 dollars.

Thx for the reply, I understand all that and it's not the issue. I'm already booked in to have it done. I am mostly curious about which tune to run that the factory 10 speed can handle under regular day to day driving, 10,000lbs camper during the summer and occasional fun here and there when I want to get on it a bit but nothing wild. I don't think I've ever been wide open throttle in any of my trucks.

In2racn · May 3, 2021

I had the exact same tank heater issue. It was the second time my truck had Limp Mode warnings in 19k miles. This was about the same time frame as your issues, mid January 2021. They had no idea when parts would be available, and I understand there were hundreds of dead 2020 L5P's sitting around North America. After sitting 3 weeks, I couldn't take it any longer, $1000 a month to sit at the dealer with no end in sight. I had the truck deleted with a lot of anxiety about the warranty. Cost me about $7k.

So far so good (about 6k miles on the delete). I have a mild towing tune (550HP) with a 4 inch pipe and muffler. I did not tune it for power, mileage or towing... I tuned it to get my truck back instead of waiting months for parts. Like you, I didnt want to roll coal or race the truck, but I do drive fast and try to keep moving in traffic. I pull snowmobiles, skid steers and dump trailers.

With the tune, it certainly has more power, the "dead pedal" is better but still not as punchy as I would like off idle. Overall, I think my deleted LML was more powerful, but that truck did not quite get as good mileage as the L5P. Maybe the 10 speed makes the mileage better? Even deleted and tuned, the 10 speed shifts smooth, although it should improve when they crack the TCM.

I recently had to run about 125 miles and was in a hurry. During the trip that included flat and hilly terrain, I ran at around 80 mph on the GPS and broke 100 mph about 3 times making passes. I averaged 26 mpg going a a good clip.

Some of these Youtube videos showing multiple 2020 L5P's blowing injectors has me very nervous.

Edited May 3, 2021 by In2racn

Brozat4 · May 4, 2021

In2racn, thank you for chiming in. I feel like we have similar driving habits. I never really brat on my truck but I do like a bit of get uo and go.

It sounds like you are happy with your decision overall so thats good to hear. I finally get to have mine done this Thursday... I have had to push my appointment back 4 times because of work and it's driving me insane lol. Do you have a single tune or did you go with the shift on the fly tunes that are out now?

In regards to the injectors, I try not to worry about that too much... the amount of trucks on the road vs the amount of L5P with injector issues is nothing to worry about. I mean it can happen, but so can anything else right?

I am looking forward to joining the club. I will let you know my thoughts once I get some km on it. On a side note, my Wehrli came in just in time!

In2racn · May 4, 2021

Good luck with the delete. My truck is running well.

I wish I never had to delete. My 2020 was extremely quiet in the cab, had enough power and I didn't mind DEF fluid refills. The biggest problem is Check Engine lights... and even the lights don't bother me if they came on like a gas truck. In another words, "Oh ******,another CEL, I need to get that fixed before the next inspection or I need to make an appointment". But no, I HATE when my truck threatens me with limp mode. In past years, it would be 3AM deep in Quebec, 20 below zero, on the way back to NY after a snowmobile ride and I would get the "Speed limited in 47 miles". This should be against the law. I am not sure if it is required of the OEM's to do this, but it is total BS. One time on my 2011, my tank heater went when I was miles from home.... it was 90 degrees outside! No tank heater needed... yet my truck threatened limp mode. If the EPA, Emissions idiots want us to comply, how about making it reasonable? Any way... rant over...

As I hinted at, I enjoyed the ultra quiet cab of the 2020... the delete, even with a muffler is certainly more noisy than stock. At certain loads and RPM levels, the truck resonates in the cab, a bit of a droning sound. Going to manual and downshifting gets rid of the howl. It it not a big deal and I have gotten used to it, but I miss my "Cadillac-like" quiet cab. However, on the other hand, under acceleration, passing, climbing hills, it is cool to hear the real rumble of a 500+ horse diesel.

I do not have the multi-tune SOTF as of yet. I was hesitant at first. I figured, less options and tunes, less chance of CEL or issues. But, the more I read and hear, it appears the tuners have the SOTF bug-free, so I may add that to my truck.

I see you have the cool intake stuff... please keep me posted on how that works and how your tune comes out. Also, I would be interested on what the 5 tunes are on the SOTF.... do they simply alter the HP produced with each tune?

Stay in touch, good luck to both of us with our unwarranted $80K vehicles! Well.... $85K after you count the 6 - 8K on a delete. (We need to have our heads checked!)

Edited May 4, 2021 by In2racn

Brozat4 · May 8, 2021

Well got it done and it runs and shifts as good as stock, only now it has grunt and power. I opted for the 5" with muffler and it definately times the sound down under normal driving and my wife describes the truck sounds like a monster under some desent acceleration lol.

I got some information on the SOTF tuning and it is in fact 5 separate tunes that you switch between. Not just 5 fuel scaling settings. Well there is technically 6 tunes because 0 counts as stock. The tunes I got are done in house as it is a diesel race shop and they have access to a dyno.

0 - Optimized Stock

1 - 50 WHP Heavy Tow

2 - 85 WHP Light Tow

3 - 125 WHP Street

4 - 150 WHP Race

5 - 175 WHP Max Effort

I have really only played with Tune 1 and 2 as there I no Trans tuning for the 10 speed yet. The difference between the two is quite significant so I can't imagine the other 3... During the tank of fuel over 1149km I averaged 10.9 L/100km and that was about a 50/50 mix of hiway and city driving so not bad.

One thing worth noting for others who are curious is that even with a muffler setup, the drone at 110km-120km is still there. You don't have to raise your voice to talk to passengers but you definitely hear it if the music volume is low. I'll leave it be for now but I might throw in a Flo Pro Twister Resonator in prior to the muffler to see if that helps any. I absolutely love the sound it makes under load, I am just not sure if my wife will put up with the minor drone on long road trips with our son but we will see.

Overall I am supper happy and am excited to put some miles on it now more than ever.

If anybody has any questions feel free to send them my way and I will do my best to answer them.

In2racn · May 16, 2021

Awesome to hear you got it done and are happy. I also experience intense "droning" at around 65 mph. I will be very interested in your results should you try the resonator.

The "heavy tow" tune actually has less HP gain than the light tow? Is this because of a loss of torque?