How much does your MPG drop during regen? Mine was reading at 19.2 when I got the notice pop up that exhaust cleaning was being performed. My MPG then dropped below 13 within 2 miles. Anybody pay much attention to this?

 

No because it is not like I can do anything about it. I do note that my regenerations last about 13 miles at 65 mph. I wonder if it varies as the truck get more miles on them and presumably ash starts to build up in the filter??

 

I feel like I'm missing something. I have just over 4k on my truck and have yet to see the message. Of course my engine light has been on since the 1k mark due to a faulty EGR valve which the dealer can't get until Dec. 15th.

 

I have never seen that kind of drop. I used to watch for the regen message and monitor the mileage drop. The biggest drop I noted was around 2 mpg and that is with winter fuel. I quit worrying about it.

 

I actually tried to track the regen messages manually to calculate the MPG impact. Gave up on that after about 300 miles. It's just near impossible to catch all the Cleaning Exhaust Filter messages because they come and go so fast (as evidenced by guys who say they've driven thousands of miles and never seen a message). That is possible with all the passive regen going on but it is so easy to miss the message on the driver information screen.

 

I haven't been able to figure what the actual impact to MPG is because I usually notice the avg MPG start dropping when it otherwise wouldn't.

Dang, your post just gave me a new task.

Next time that I notice regen taking place (and I am on a stretch of road that allows) I am going to reset my average MPH and when it completes the regen I will reset it again and back calculate the difference in MPH.

This will probably be a complete waste of time because there is nothing that I know of that I can to to minimize regens or increase fuel economy during them.

 

I get about the same amount of drop on the instant MPG gauge (the green bar). If it is hovering around 20 when a regen starts it'll immediately start hovering around 10-12 for the duration of the regen. If I miss the "cleaning" message I know exactly when one is happening by looking at the instant mpg gauge.

This tells me that some part of the system knows full well that fuel is being used for this purpose. But it seems other parts of the system don't know: specifically the gallons used indication. After a full tank (37 gal), the gallons used always indicates somewhere around 2+ gallons low so it seems that the regen fuel is not being accounted for there. That's my theory and I'm sticking to it.

 

[quote=AlexWV;9648200]I get about the same amount of drop on the instant MPG gauge (the green bar). If it is hovering around 20 when a regen starts it'll immediately start hovering around 10-12 for the duration of the regen. If I miss the "cleaning" message I know exactly when one is happening by looking at the instant mpg gauge.

quote]

Alex - I think I understand what you are saying, but always considered the instant MPG bar to be a percentage of scale. I will get all bars while traveling at 30 MPH, will also get all bars while traveling at 55 MPH. So, I can't seem to figure out how much fuel is used during regen or the "actual" impact on fuel economy.

I am going to make an attempt to understand the impact at various speeds, etc. As I said - this is probably a total waste of time, but I am interested in understanding the impact.

 

[quote=Adobe 11SD;9648512]Do we have the same instant MPG bar?

I have the info center screen in between the tach and the speedo. The "Fuel Economy" screen shows an instant mpg bar from 0 to 30 MPG with a scale line at 0, 10, 20 and 30 mpg. Anywhere in between the lines you have to guesstimate.

The instant bar changes constantly with any minor input to the go pedal or any slight deviation in the road incline/decline.

The "Fuel Economy" screen also shows average mpg (since the last reset) and that one doesn't change as frequently depending on how long ago it was reset.

It is almost impossible for me figure out any mpg impact using these other than being able to tell beyond the shadow of a doubt that a regen is in progress.

The way I have been attempting to gauge the impact of regen on mpg is by using the "gallons used" indication. I reset one trip meter every time I fill up and keep track of gallons I put in vs "gallons used" and, as I mentioned, I always put in 2 or more gallons vs what is indicated. The % difference is usually around 7-8% and that correlates perfectly to the % error in the indicated mpg (from the trip meter) for the tank.

So I'm going to throw out 7-8% as the answer. What do others think?

 

[quote=AlexWV;9648632]I don't have the message/info center and miss all of the cool things that it does. That is one of the things that I didn't really think about when I purchased my truck - mistake.

Now you are going to make me go out to the truck and make sure I have not misread the scale.


Nope -- just checked and I only have up and down arrows. The owner's guide does not say anything (that I can find) to indicate each segment of the bar = 5 MPG or anything else that would allow me to understand the actual MPG. I think this this is just a graphical economy indicator that is not really intended to allow us to determine MPG, rather it is to allow us to see the effects of how we are driving. I dunno.

 

It's easy for me to catch just about every Cleaning Exhaust Filter message. They all seem to appear whenever I'm 5 miles or less from any particular destination.

Otherwise, I'd say Adobe 11SD's 7-8% estimate is pretty close to what I've seen.

Joe

 

I think the regen learns our routine and starts at the most inconvenient times on purpose, such as a half mile from the office as I drive back from lunch in town.

Disclaimer: I'm just being funny, this is in no way a fact.

 

I was cruising along going down hill coming out of the Orange County Mission Viejo area and over about 10 miles my MPG was about 21.4.
I missed the warning message but noticed in horror that my MPG started dropping dramatically. From 21.4 down to 15.8, All in about 8 miles. Luckily, I remembered reading something about this happening and I didn't think the truck was broken. I think it recovered back to 18.1 but it was crazy. I've since seen the message but you have to be paying attention.
I'd like to figure out a way to shut that off and remove that filter or something. Seems like a huge waste of fuel.

 

Regen costs me about 30miles or a tad over 2 gallons every time it runs to completion on my '10.

When I fill up, I reset my trip meter and note my miles-to-empty. For the duration of the tank, my miles-to-empty + trip meter hover around the same total +/- a few, but after a regen starts and ends, I'm down at least 30miles.

The mpg meter on mine is fairly accurate compared to hand-calcs if you never reset it. It appears to be a running average over several tanks of fuel.

7-8% seems about right even on my '10... more if i'm in stop-and-go traffic. I've been noting just about every regen I've had along with how long each one has been.

 

No wonder the 6.4 guys are trading up to 2011. I am no math whiz but my truck loses at the most 12% while regenerating for 10 minutes. If I am getting 17mpg and it drops to 15mpg for 10 minutes...aw never mind my head hurts. I am thinking it will not amount to a cupful per regeneration...