No DEF usage?
Thread Starter
|
Senior User
Joined: Sep 2016
Posts: 192
Likes: 52
No DEF usage?
Ok, I'm new to diesels, just got mine less than a month ago. I've now put 850 miles on it and the DEF gauge hasn't moved off of full. Also, the range for the DEF has gone from 6500 to 6000, back to 6500, up through 7000, 7500, 8000, and it's been at 8500 for the last couple weeks.
Again, I'm new to diesels, but this just doesn't seem right.
Again, I'm new to diesels, but this just doesn't seem right.
Tuned
Joined: Jul 2003
Posts: 274
Likes: 20
DEF is really only used heavily when the engine is running hot, as when towing a heavy trailer or driving in mountainous terrain. Even then, the gauge will drop slowly and you'll get 2500ish miles from a tank of DEF. If you are not towing heavy, you may get 6000+ miles from a tank. I wouldn't have expected your gauge to move at all in 850 miles. so all is well.
Lead Driver
Joined: Nov 2005
Posts: 5,227
Likes: 4,240
From: Kaysville Utah
Don't sweat it. It'll last 6,000-7,000 miles
DEF is consumed when the EGT's are high. That's when NOx is products and that is what the DEF cleans up.
High EGTs are produced basically when you are pushing turbo boost through the combustion chamber
So light driving, even 70 mph on the freeway at cruise, just doesn't use much DEF.
Hook up a 13,000 lbs trailer and tow up a k7% grade and you will see the DEF gauge move.
DEF is consumed when the EGT's are high. That's when NOx is products and that is what the DEF cleans up.
High EGTs are produced basically when you are pushing turbo boost through the combustion chamber
So light driving, even 70 mph on the freeway at cruise, just doesn't use much DEF.
Hook up a 13,000 lbs trailer and tow up a k7% grade and you will see the DEF gauge move.
Tuned
Joined: Jul 2003
Posts: 274
Likes: 20
Mine definitely does not do that! It will move down through the range over time, and only when it shows quite low will I get the 500 mile warning. It doesn't sound like yours is working correctly.
Thread Starter
|
Senior User
Joined: Sep 2016
Posts: 192
Likes: 52
To all that replied, thank you for your input. I haven't towed anything yet, or done any "extreme" driving. Even when I do tow it will most likely either be our 7900lbs GVWR travel trailer or our 7000lbs GVWR car trailer with the Jeep. There may be occasions when I tow something heavier, but that will be very rare.
So I'll either get a lot of miles out of a tank of DEF or I'll get a sudden surprise that it's empty.
Cargo Master
Joined: Feb 2015
Posts: 2,338
Likes: 255
From: Livermore Ca.
In 800 miles you have had only 1 regen. Don't worry about the def level. When you get the message 500 miles till limp mode then add a couple boxes to fill up the system. It's not good to keep it full all the time. It throws the sensors off and cause a fault. The sensors expect to change and by topping the tank off all the time doesn't let the truck know its working. and will throw a code. you can not reset the DEF code. Once it's on its on. Just drive your truck don't worry do the proper maintenance buy your fuel at a station that sells lots of diesel and your truck will be just fine.
Trending Topics
Super Moderator
Joined: Aug 2008
Posts: 37,379
Likes: 1,863
From: Frederick, MD
Mine will drink it pretty heavy and I average about 2500 miles per tank,
Plus side is I would rather add def then have the truck regen.
Plus side is I would rather add def then have the truck regen.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
Rezvani's Latest Post-Apocalytic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
Lead Driver
Joined: Nov 2005
Posts: 5,227
Likes: 4,240
From: Kaysville Utah
In 800 miles you have had only 1 regen. Don't worry about the def level. When you get the message 500 miles till limp mode then add a couple boxes to fill up the system. It's not good to keep it full all the time. It throws the sensors off and cause a fault. The sensors expect to change and by topping the tank off all the time doesn't let the truck know its working. and will throw a code. you can not reset the DEF code..
DEF and REGEN are two different pollution devices. Regen is dealing with soot, DEF is dealing with NOx that is caused at high combustion temps. ( Usually when the turbo is boosting combustion chamber pressure) Using lots of DEF doesn't mean you are doing fewer regens.
Cargo Master
Joined: Feb 2015
Posts: 2,338
Likes: 255
From: Livermore Ca.
My 500 mile message came on yesterday. It wont even take 2 full boxes. The 17 guys are lucky. There DEF tank is bigger and will use 2 boxes easy
I hate having DEF left over in the box.
When the tank says under half full my truck won't take a full box. so I just wait till the message comes on.
I hate having DEF left over in the box.
When the tank says under half full my truck won't take a full box. so I just wait till the message comes on.
Cargo Master
Joined: Feb 2015
Posts: 2,338
Likes: 255
From: Livermore Ca.
Well I wnt and bought 2 boxes of DEF. Truck only took most of one box. This is starting to get old. I want to keep my truck in great shape but this DEF crap is getting on my nerves. Going out with my Forscan and see if I can clear the light. I don't want to pay the dealer $230 just to look at the truck.
Cargo Master
Joined: Feb 2015
Posts: 2,338
Likes: 255
From: Livermore Ca.
The light went off. I did a couple key cycles then the truck sat overnight. Got up Sunday and truck is fixed. It has been a long time sinse I have had to add DEF to the truck. Maybe the dealer keeps topping off my def and the truck thinks its not using any def. Just a guess.
More Turbo
Joined: Oct 2003
Posts: 597
Likes: 22
From: Central Maine
I'm the opposite school of thought, I never let mine get empty. In 11 years and Half a million miles of driving trucks with DEF, I 've only seen the 500 miles to empty message twice and both times I had problems. I think if the tank gets too low the DEF crystalizes in the empty part of the tank and can lock up the sensors. I've just had better luck filling it up before it gets low. Anytime it gets below half a tank and I'm by a DEF pump, I top off.
DEF and REGEN are two different pollution devices. Regen is dealing with soot, DEF is dealing with NOx that is caused at high combustion temps. ( Usually when the turbo is boosting combustion chamber pressure) Using lots of DEF doesn't mean you are doing fewer regens.
DEF and REGEN are two different pollution devices. Regen is dealing with soot, DEF is dealing with NOx that is caused at high combustion temps. ( Usually when the turbo is boosting combustion chamber pressure) Using lots of DEF doesn't mean you are doing fewer regens.
Cargo Master
Joined: Feb 2015
Posts: 2,338
Likes: 255
From: Livermore Ca.
Problem with that is the truck might think you aren't using DEF and throw a caution light. Looks like mine did just that. I believe every time I took the truck in for service they topped it off. My light came on and didn't even take 1 box. Y