New 6.7 owner with DEF issues and loss of mpg

[Imarkdirt]

First the niceties. Thanks to everyone here. I consider this my first stop for up to date information and honest answers.

 

Now the problem. I have a 22 F250 Platinum with the 6.7. It currently has 7800 miles on it. When this truck had approximately 3000 miles I saw that the DEF tank was half full, and since I was at walmart, I got a jug. I added the 2.5 gallons and thought nothing of it. Immediately after, say within 50 miles, I noticed a drop in mpg and the truck felt more sluggish. This wasn't .5 of a mpg, this was 2.5 mpg. From a solid 19 to 16.5. I didn't think too much about it, blamed it on my heavy foot from time to time, and kept on driving. Not long after, I got my first check engine light and the dreaded 50 miles to 50 mph warning. I took it to two dealers. The first basically wanted me to leave the truck for a week while they did nothing to it, but the second was able to help me that day. Just like most here, it is a work truck with bed slide and camper top so I can't just leave it or switch vehicles but I digress. That dealer told me the injector was bad for the DEF, replaced it under warranty and sent me on my way within 2 hours.

 

Fast forward to last week when filling up at a truck stop, I noticed that I had 500 miles to empty for the DEF again. I used the pump to put 6.2 gallons of DEF in it and filled er up. Strangely now I seem to be having the exact same issue with it as I did when the injector went bad the first time. My mpg has dropped to 16.5 again, and the truck is definitely down on power. So far I haven't seen the check engine light nor have I gotten any warnings, but I am concerned that something is terribly wrong.

 

First, am I doing something wrong? I don't believe I am, but want to ask. Secondly, what could be happening to my basically brand new truck?

 

Any help would be greatly appreciated.

[4thTimer]

Following. 

[787Toolman]

I found this video; this may help you figure out your issue.  I suspect the DPF muffler is clogged and is not getting cleaned thru normal regeneration cycles, but I'm just taking a stab what your issue is and I'm just trying to help.  A good dealer and technician should have checked to ensure your DPF is not clogged.  I'm not sure if this will also explain the extra consumption of DEF but it may be a symptom of the same issue, but I'm not certain.  I'm pretty sure you can manually invoke a DPF regen cycle from your steering wheel menu buttons and select from your instrument cluster screen, but I haven't ever done it on my 2017 6.7L F350 Platinum, mine always works good on its own.

DPF Regeneration Overview | Ford Tech Talk - YouTube

787Toolman

[IA Diver]

I never buy DEF at Walmart. Some of the honest people who shop there buy DEF, and then return water in the jug for their money back....Have seen it a few times.

[787Toolman]

This graphic shows how the entire 6.7L engine system is laid out and you can see where the DEF gets injected.  If the DEF fluid is of poor quality or like IA Driver said, water and the system is not performing its intended purpose, the DPF will get clogged and cause low power.  But since you said you got DEF from a station and had same issue, I'm not sure.  What I'm pretty certain of is, if the DPF is clogged, you will have low power and probably higher fuel consumption which is what you said is happening.  The graphic is from a 2017 service book.

 

[Imarkdirt]

28 minutes ago, IA Diver said:

I never buy DEF at Walmart. Some of the honest people who shop there buy DEF, and then return water in the jug for their money back....Have seen it a few times.

Thanks for the tip. I will keep that in mind.

[Imarkdirt]

17 minutes ago, 787Toolman said:

This graphic shows how the entire 6.7L engine system is laid out and you can see where the DEF gets injected.  If the DEF fluid is of poor quality or like IA Driver said, water and the system is not performing its intended purpose, the DPF will get clogged and cause low power.  But since you said you got DEF from a station and had same issue, I'm not sure.  What I'm pretty certain of is, if the DPF is clogged, you will have low power and probably higher fuel consumption which is what you said is happening.  The graphic is from a 2017 service book.

 

Thank you for the information. I have never seen anything on the dash regarding the exhaust or that the filter is clogged. My friend who has had two of these 6.7's (a 2016 and currently has a 2011) said when his goes through a cycle it is pretty evident and he gets a light on his dash. I have never seen that at all. My trips are generally not short. I routinely travel 40 to 50 highway miles at a time. I honestly thought it was smart enough to take care of itself as long as I kept the DEF tank with fluid. If I find out what the cause is I will reply with the answer.

 

 

[787Toolman]

15 minutes ago, Imarkdirt said:

Thank you for the information. I have never seen anything on the dash regarding the exhaust or that the filter is clogged. My friend who has had two of these 6.7's (a 2016 and currently has a 2011) said when his goes through a cycle it is pretty evident and he gets a light on his dash. I have never seen that at all. My trips are generally not short. I routinely travel 40 to 50 highway miles at a time. I honestly thought it was smart enough to take care of itself as long as I kept the DEF tank with fluid. If I find out what the cause is I will reply with the answer.

 

 

It does take care of itself, as long as everything is working as designed and the DEF is the real stuff and not water.  However, you can invoke a regen cycle manually if you want to clean it at a specific time and not wait for it to perform an auto regen.  However for too many short runs, it might never get a chance to regen.

[787Toolman]

I checked my 2017 F350 6.7L and I don't have the ability to start a manual regen cycle so apparently that is a high-level setting that needs to be changed to allow it.  I will research this as I'd like to be able to command a regen since I drive a short 26 mile drive twice daily which may not allow an automatic regen to occur often enough.

[Imarkdirt]

On 3/21/2022 at 7:44 PM, 787Toolman said:

I checked my 2017 F350 6.7L and I don't have the ability to start a manual regen cycle so apparently that is a high-level setting that needs to be changed to allow it.  I will research this as I'd like to be able to command a regen since I drive a short 26 mile drive twice daily which may not allow an automatic regen to occur often enough.

I looked through all my settings. It wasn't there either. Not sure what else I can do but wait for a light and take care of it then.

Thanks for your help.

 

 

[Forderorder]

19 minutes ago, Imarkdirt said:

I looked through all my settings. It wasn't there either. Not sure what else I can do but wait for a light and take care of it then.

Thanks for your help.

 

 

You have to order the truck with option 98R "Operator Commanded Regen" or use Forscan to enable it.

[Imarkdirt]

Update:

 

Still no change in mpg. It also hasn't popped any codes or check engine light warnings. Odd thing is that the DEF tank mileage indicator, which originally showed 6500 miles to empty when I filled that tank up, now says 4500 miles but the tank shows 100% full. I have put approximately 1200 miles on it since putting DEF in it. I think it is going to need some time at the dealer though to get this sorted out. Can't say I am looking forward to that.

[road turtle]

On 4/2/2022 at 11:08 AM, Imarkdirt said:

Update:

 

Still no change in mpg. It also hasn't popped any codes or check engine light warnings. Odd thing is that the DEF tank mileage indicator, which originally showed 6500 miles to empty when I filled that tank up, now says 4500 miles but the tank shows 100% full. I have put approximately 1200 miles on it since putting DEF in it. I think it is going to need some time at the dealer though to get this sorted out. Can't say I am looking forward to that.

WRT to def levels.  I started the trip home with a full def tank, and it was showing 7000 miles to empty.  After towing for about 300 mile, it dropped to 2000 miles.  Another roughly 300 miles, was down to 600 miles, and yet still showed 1/2 tank.  It appears short local trips did not use hardly any def, but towing a 13k 5th wheel going up into the mountains just sucks down the def.  I'm going fill up again, and hopefully that will get me the rest of the way home.

[Imarkdirt]

On 4/3/2022 at 11:06 AM, road turtle said:

WRT to def levels.  I started the trip home with a full def tank, and it was showing 7000 miles to empty.  After towing for about 300 mile, it dropped to 2000 miles.  Another roughly 300 miles, was down to 600 miles, and yet still showed 1/2 tank.  It appears short local trips did not use hardly any def, but towing a 13k 5th wheel going up into the mountains just sucks down the def.  I'm going fill up again, and hopefully that will get me the rest of the way home.

I don't put much stock in the mileage estimation, but the fact the tank level hasn't dropped at all is bothering me. I had bad luck with my last truck (an F150 with 3.5 ecoboost) so was hoping this would make up for it. I am not towing, but I keep 700 pounds or so in the bed at all times with my bedslide and camper top.  IDK what is going on with it.

 

Thanks for your input.