Crazy MPGs

[notlimah]

So not sure exactly what's going on right now, but I don't think it's a bad thing.

 

I filled up my last tank and up until yesterday I thought my fuel gauge was stuck! It FINALLY dropped off the full peg and is starting to get under the first tic mark. I'm currently sitting at over 100 miles on my trip counter. The only thing that's changed from this fill up from previous is I set the smarty to fuel mode. Does it really cause this big of a jump in MPGs?

[Silverdodge]

My old cummins and my current one do the same thing takes forever to get off full about 100 miles or so then another hundred to 3/4 then 200 to half ish I never really run below half lol but on my old one I went on a 600 mile road trip on 3/4s of a tank it's a cummins thing I guess my new one eats fuel like no other when I start getting on it in hot unlock 

[dodgedieselnewbie]

What kind of crazy mpgs are you getting? What were you getting before? Mine are crazily inconsistent.. 

[Mopar1973Man]

Catch me if you can... Warm IAT temps are back and low cetane fuels have returned...

[dripley]

Fill it up and just see what you really have. On pure highway run I can get about 425 miles out of the first half a tank, but only 225 out of the second half. It used to be the reverse until I had the in tank pump installed. It then changed a little after installing my AD. 

[JAG1]

42 minutes ago, dripley said:

Fill it up and just see what you really have. On pure highway run I can get about 425 miles out of the first half a tank, but only 225 out of the second half. It used to be the reverse until I had the in tank pump installed. It then changed a little after installing my AD. 

No fair counting that fried chicken oil you put in there.

[dodgedieselnewbie]

I haven't done a highway trip in awhile. I am averaging 16.. stop and go around town. This is hauling around a small utility trailer most of the day.. weighing roughly 2000# loaded. I have a bedslide as well as a cap. I also carry a decent amount of tools and gear in back seat.  Does this seem reasonable?  

 

If I bump up injectors to say 75-90s .. can I see an increase?

Edited April 13, 2016 by dodgedieselnewbie

[notlimah]

It hasn't even hit a 1/4 or 1/8 marker for me to run numbers somewhat accurately yet lol. I guess this is just the first time I noticed the slow fuel drop from full. My other truck was the opposite so that's what seemed odd to me.

[CSM]

Be careful.  When my fuel sending unit failed it did the same thing.   It would read higher and higher as it wore out.  I ended up empty with a quarter tank left. 

[TFaoro]

11 hours ago, notlimah said:

So not sure exactly what's going on right now, but I don't think it's a bad thing.

 

I filled up my last tank and up until yesterday I thought my fuel gauge was stuck! It FINALLY dropped off the full peg and is starting to get under the first tic mark. I'm currently sitting at over 100 miles on my trip counter. The only thing that's changed from this fill up from previous is I set the smarty to fuel mode. Does it really cause this big of a jump in MPGs?

Yes it does cause that big of a jump. On the highway, my fuel gauge typically doesn't move off of full until 100-115 miles.

[Dieselfuture]

Call me crazy but I lost mpg (about 2 mpg ) going from 75hp 8 hole to 60hp 7 hole. I think 8 hole may have better atomization. Some day I'll prove myself wrong when I'll switch back. 

[TFaoro]

1 hour ago, Dieselfuture said:

Call me crazy but I lost mpg (about 2 mpg ) going from 75hp 8 hole to 60hp 7 hole. I think 8 hole may have better atomization. Some day I'll prove myself wrong when I'll switch back. 

What were the two mpg numbers?

[notlimah]

2 hours ago, TFaoro said:

Yes it does cause that big of a jump. On the highway, my fuel gauge typically doesn't move off of full until 100-115 miles.

 

I mean I'm not complaining! But man that's a massive improvement! I was running it between catcher 3 & 5 the last tank and I think my average mpg's were like 14

5 hours ago, Mopar1973Man said:

Catch me if you can... Warm IAT temps are back and low cetane fuels have returned...

 

Those are some nice looking numbers there! I'll do my best!

 

Side note... is highway diesel a nono? I was just thinking, I'm pretty sure the pump I filled up at was highway diesel. What's weird though is I typically fill up at the same pump all the time but it said that it was out of fuel, so I literally drove around to the other side of the same pump and it had fuel, but I noticed a sticker that said highway diesel. Not sure if that was true or not, but just a thought.

[TFaoro]

Like semi truck diesel? It should all be the same. I typically avoid using the semi pumps because they don't have a filter on most of them. It's usually just a screen to stop debris. Regular pumps usually have a 30 micron filter if I remember correctly. 

[notlimah]

I dunno exactly. It just said highway diesel and its here on base so I'm not sure if that's even something they have on there typically. I'll ask my cousin since he's the one that runs that side of the operations.

[Mopar1973Man]

4 hours ago, TFaoro said:

Regular pumps usually have a 30 micron filter if I remember correctly. 

 

Not all... I've done my research here and some of the Mom and Pop places don't have filters or also using screens. Now most name brand places have standard and will keep to those standards typically. Even worse some are still using mechanical pumps with mechanical price boards. Those I don't even stop at...

Edited April 13, 2016 by Mopar1973Man

[Dieselfuture]

7 hours ago, TFaoro said:

What were the two mpg numbers?

About 20-21 hwy with 8 hole and now same tune and driving stile 17-18hwy. Empty that is at 65-68mph

[01cummins4ever]

6 hours ago, notlimah said:

I dunno exactly. It just said highway diesel and its here on base so I'm not sure if that's even something they have on there typically. I'll ask my cousin since he's the one that runs that side of the operations.

Highway diesel is #2 diesel, the same fuel all road users use. As long as it'd doesn't say off road or dyed diesel your safe, not that their is anything wrong with it, it's just non taxed.

I expect to see a 1 or 2 jump in mpg now that suppliers are not using the winter blend fuel now.

[dripley]

When mine was new I used to get 17 mpg running the interstate around 75 mph. Over the years I have done 3 performance upgrades. The first was the Banks Stinger Plus system. While I got good power out of the mileage remained the same. Not a bad thing, 75 hp, that I used a lot, and no mpg loss. The next was RV275's and I pickup 1 mpg. Now i am 18 mpg. The third is the edge comp I installed after the banks tuner crapped out. I picked up another 1 mpg. So now running 75 I am getting 19 mpg. The extra power is nice and I do used it. The long highway trips I make it is not really needed. For now running about 600 miles a week 65/35 highway and in town and getting 16 mpg. I cant complain with a truck that weigh 7500 pounds.

[dodgedieselnewbie]

I would love to see my fuel gauge trickle down from full... but it won't go past the half mark on fill up.. lol  What do I need to fix that??

 

Any comment on whether 75-90 injectors would increase MPGs?