300 mpg DEF?

[Powder Extreme]

So I just returned from a trip pulling an enclosed v-nose trailer weighing about 8,000lbs. Obviously not a huge load but certainly not empty. In 1,500 miles I burned through 5 gallons of DEF, I put in a 2.5 gallon jug and drove another 750 miles then the low DEF warning came on again. That equates to 300mpg. Isn't that pretty excessive? My old '13 DRW would get 7-800 pulling my 5th wheel which is a heck of a lot more load than this trailer.

Anybody else seeing DEF usage like this when loaded?

 

[gsbrockman]

I can't see how one can accurately determine their DEF consumption adding DEF 2.5 gallons at a time...

 

[RustyJC]

Cummins says DEF usage should be 2% to 3% of fuel usage - 2 to 3 gallons of DEF per 100 gallons of fuel. Since you don't mention your fuel consumption, it's hard to evaluate whether your DEF consumption is excessive or not.

Rusty

 

[TRAMPLINEMAN]

Rusty, is that based off running empty or loaded/towing? I know every truck and situation is different, but it seems like 2-3 gallons of def per 100 gallons of fuel is excessive. I do know that when I'm towing it does use more def, but running empty I can go thousands of miles on 2.5 gallons. Not trying to start an arguement, just curious.

 

[NIsaacs]

Rusty, is that based off running empty or loaded/towing?

I would think the formula Rusty posted would apply loaded or empty. "2% to 3% of fuel usage"

Nick

 

[RustyJC]

Yep, it pretty much applies loaded or empty. Your truck uses more fuel towing, so DEF consumption will go up proportionately with fuel consumption. If you're getting ~20 MPG running unloaded on the highway, that would be 2000 miles per 2-3 gallons of DEF.

Rusty

 

[Hoefler]

When towing my 16K fifth wheel, I usually consume 5 gal of DEF every 900-1000 miles. I run it until I get the refill warning, an add 5 gal at a time.

 

[EDankievitch]

I use around 1 gal per 500 miles when towing but I'm towing a boat not a huge box like camper..... That said I don't think a gal per 300 miles is that far off. I did however have an issue last trip where I got a CEL and the truck went into a different op mode and my DEF usage went up and my fuel MPG's went down. Turns out there was a flash for just the issue I had. Off the top of my head I don't recall the code that came up. I'd stop in and see your friendly RAM service dept and see if there are any new flashes for you'r rig

 

[TCDiesel]

Power extreme, At times when I get out your way My trucks drink DEF at 250-300PG, pulling My enclosed V-nose 4 place Trailer. We are make are own DEF so its about $1.00PG.At times I just use Deionized water in summer months.

 

[Brocky]

When my truck was first new it drank a lot of DEF, guessing in the 300 MPG range empty. After my first service it improved a lot!! May have been a computer update??? Not real close figures, but around 500 MPG loaded @23000# and better than 800 empty. I have the 9 gal tank and let it drop below a 1/4 into the red once and the warning light came on it took 7.5 gal and was not full.. At just below 3/4 I can put in 5 gal and not have it gurgle like full. I do NOT depend on the gauge!!! When it gets down to 1/2 to 3/4 I just throw in 5 gal.

 

[Powder Extreme]

Put 2.5 gallons in when the 5mph warning comes on, drive till the 5 mph warning comes on again. Then do some simple division. What's so hard about that?

 

[Powder Extreme]

I was running right at 10mpg so that puts me a little over what Cummins says but not excessively so. Just more than it used to use pulling my 5th wheel and this is a smaller trailer.

Probably nothing to worry about.

Now if if I could just get the exhaust leak fixed when using the exhaust brake....

 

[RustyJC]

Power extreme, At times when I get out your way My trucks drink DEF at 250-300PG, pulling My enclosed V-nose 4 place Trailer. We are make are own DEF so its about $1.00PG.At times I just use Deionized water in summer months.

If your homemade DEF isn't 32.5% urea, then consumption will be higher than standard DEF. As the urea degrades, the feed rate increases to keep the NOx conversion rate constant.

Rusty

 

[TCDiesel]

If your homemade DEF isn't 32.5% urea, then consumption will be higher than standard DEF. As the urea degrades, the feed rate increases to keep the NOx conversion rate constant.

Rusty

Its seems that the rate is measured by MPG, Some OTR owners have also been using DW, without issues. how effective the system is, is questionable, IMO its all guess work, or over work on the %, injecting to much DW or DEF is not going to harm anything, it will either evaporate or leak out the site hole. My 2012 CC 4500 I sold , the owner is still using DW problem free at 220K thats almost unheard of for the that version and setup. He remove his DEF filter back in 2014 W/O issue also.