fuel

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juans 2018 Ram

Junior Member
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Jul 9, 2024
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Location
Tucson Az
Ram Year
2018
Engine
6.7 cummins diesel
Hi, my name is Juan and i'm in Tucson AZ. I'm new to this site, so I hope i'm doing this right. My question is I purchased a 2018 Ram 3500 with a 6.7 cummins diesel, I got it because I purchased a 2021 38ft travel trailer and I needed the right truck for this job. My question is I changed the original fuel tank to a 50 gal tank. Ive talked to the local dealer about any changes I have to make in order to get the right readings. Apparently they dodn't have any answers, so my question i'm asking is has anyone done this to their truck and what was done? Thank you
 

crash68

ACME product engineer
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2015
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3.0 EcoDiesel
@juans 2018 Ram the fuel gauge level will read correctly, it's only the Distance Till Empty reading which will be off slightly. I do believe there's a way to adjust the fuel tank volume which is most likely stated in liters.
 

RamDiver

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Marlborough, Ontario, Canada
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2021
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Hemi 5.7
Hi, my name is Juan and i'm in Tucson AZ. I'm new to this site, so I hope i'm doing this right. My question is I purchased a 2018 Ram 3500 with a 6.7 cummins diesel, I got it because I purchased a 2021 38ft travel trailer and I needed the right truck for this job. My question is I changed the original fuel tank to a 50 gal tank. Ive talked to the local dealer about any changes I have to make in order to get the right readings. Apparently they dodn't have any answers, so my question i'm asking is has anyone done this to their truck and what was done? Thank you

AlfaOBD will allow you to set the tank capacity in litres and there other tank tweaks available for calibration. 3.78 litres/gallon

AlfaOBD fuel cap.jpg



Any truck 2018+ will also require a security gateway bypass harness. Many users here prefer the KaodTech harness for build quality, reliability, and ease of installation.

Also, you can leave the KaodTech harness installed (tucked up under the dash) and the stealership can still have access to the OBD port. Mine has never been removed since I installed it last year.



Many users will use AlfaOBD with an Android phone or tablet while I prefer a Windows laptop. I worked most of my career in Telecom and don't trust Android with anything important, YMMV.

You will also need an interface to connect to the OBD port. I use an OBDlink SX because they're much cheaper, faster, and more reliable than most Bluetooth-type interfaces.

$50 for an OBDlink SX instead of $140 for the popular OBDlink MX+ Bluetooth interface.

https://www.amazon.com/ScanTool-OBD...=se&keywords=obdlink+sx&qid=1720621738&sr=8-1


And, welcome.gif to Ram Forum. :cool:

.
 
Last edited:

lpennock

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Nov 17, 2018
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Location
Phoenix, AZ
Ram Year
2018
Engine
5.9L & 6.7L Cummins
Have tried many setting in AlfaOBD and never been able to get DTE reading correct. Fuel Level gauge is pretty close with my Titan 55Ga with the exception there is about 10 gallon before the gauge and OBD will move off 100%. Once you run out the first 10 gallon I have found that the DTE isn't too far off. The low fuel light comes on with about 10 gallons left in the tank which also aligns with the red section on the gauge.

Here is the calibration numbers I determined on the first fill of my 55 gallon tank.
 

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