cummins 4x4 11mpg ?? how can i get 20
 

i have a 99 reg cab lwb 4x4 cummins 4 in lift 35 in mts on it and went on a trip today mostly highway miles and averaged out at 11 mpg mods to my truck include
4in exhaust turbo back(straight pipe)
edge juice with additude programmer (i had the programmer on the mileage setting)
not sure if injectors have ever been replaced
i put a lift pump on a month ago it runs at 15psi idle and round 12psi going down the highway
changed the fuel filter when i put the lp
on factory air box
any ideas on what could be the problem??

what speed were you running down the road?

I was running between 65 an 70 right at 2 grand on the rpms

for some reason i get better fuel mileage between 70-75 then i do between 65-70. not a heck of a lot maybe a mile or two. whats your air cleaner look like? i was having an issue with mileage a month or two ago after driving a lot in the desert when it was dusty. it dropped down to around 15 from 20-21. I did a full filter service and it shot my mileage back up (air,oil,fuel). i noticed that if I am getting closer to 5000 on an oil change i loose about 1 mpg highway too. try hosing out your intercooler/radiator. idk where your from but a lot of debris in there can limit the effectiveness of your intercooler too. might sound weird but it works in my truck.:tu:

i get my best fuel mileage with the juice set on level 5. most of the guys around here do to i believe.. try that and see how it works for ya.. also i have my settings all on 5 too
1x5
2x5
3x5
4x5
5x5

Really 5 with the fuel up ? I'm been debating on going to a bhaf

i drove mine with it on economy for a while and didnt really notice a gain so talked to one of the guys on here he said try the level 5 i did and i average anywhere from 18-22mpg depending on how you drive it..If you get in it and blow smoke all the time then this above wont happen either, i romp it every now and again but mainly 60-65mph I am also running a smaller tire than what you are a 285/75/16, the bhaf is a good cheap filter cheaper than the rest that is. I have been happy with mine so far

Could u tell a mpg diff in it ?

in the bhaf??? maybe a little, i put it on after i already had the edge on and my airdog 150 that is what i would say helped me the most and then the addition of the bhaf

I plan on doing the bhaf and cleaning the map and iat sensors in the next few days the truck has a new lp or I would upgrade to the air dog system

sounds like a plan let us know how it works out for you.. do you have a manual or auto tranny???

Auto

11mpg?! ouch...


I did 15.5 when I filled up last night as well as the fill-up before that.


since you have oversized tires, is your speedometer corrected for the tire size? where are you getting your miles per tank from?


I use my in-dash navigation to pull miles since my speedometer is off. GPS doesn't care about your tire size :tu:

I used a GPS to find my miles

clean your MAP and IAT sensors. might help a bit.

128:1 mix of 2-cycle oil helps slightly as well + it helps lubricate the injection pump.

Just got done cleaning them ill try the 2 stroke oil also
Have a bhaf ordered gona try that to

make sure it is TC-W3 2-cycle oil (like wally world supertech) you want it to be ashless so it doesn't add carbon buildup in the motor.

So you are basically adding 1qt 2cycle oil to a full tank of fuel?

I have also heard of people mixing in used tranny fluid in their fuel, has anyone else heard of this?

Tagged

DS

sent from the Honey Badger Nexus

i have seen people use ATF fluid but that was in a powerstroke, but haven't seen it in a cummins. not to say it wouldnt work just saying idk anyone who has used it. the guy with the 7.3 had a transmission shop and he ran it through a few filters, and im pretty sure he cut it with diesel too. if you google it you can prolly find the article. IDK how it does for fuel mileage though. I also get better fuel mileage with my tuner on the power setting. i have a quadzilla xzt+ so it only has three settings. power, mileage and stock. You just have to keep your foot out of it. Are you running any mufflers or cats?

Many years ago tranny fluid in the fuel worked pretty well. Now the tranny fluids have changed a lot and so have the diesel fuel systems. I wouldn't use it and particularly in a VP-44 engine since the IP is so sensitive to being lubricated properly through the fuel itself. JMHO.

yes people have used ATF, however it is not good for the engine...ATF is not ashless, therefor it will build up quite a bit of carbon deposits on the injectors, valves, exhaust manifold, and turbine and turbine housing on your turbo.

that is why I only recommend ashless 2-cycle oil...and as far as the 2-cycle oil goes, do NOT use it on a 6.7L truck that has not had EGR and DPF deletes. if the deletes are done then it's fine to run, but with DPF and EGR in place it will clog up the intake and DPF faster.


yes 1oz per gallon or 1qt per 32 gallon fillup.

info of what works, how well it works, and what doesn't work...

also note I recommend a stronger mix of 2-cycle vs what was tested on the chart...
Attachment 34755
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as a update on the fuel mileage cleaned the iat and map sensors upgraded from factory airbox and fiilter to a bhaf and ran my edge on 5 on the same trip i avgeraged out at 14mpg but that still isnt the 18 to 20 everyone talks about
did not have a chance to try the 2 stroke oil though planing that on the next tank

You're probably not gonna see 20 with lift and big tires :c:

get a smarty. It can correct your speedo for tire size

I have been using atf for 5 yrs in both of my truck ( 87 f-250 7.3IDI & 95 12V ) ... no issues and I have the 7.3's heads off and thier real clean ..... was super suprised ... i can post pics ...

My friend has an 04 5.9l and I noticed the same thing if he ran his edge n stage 6 he got about 19.2. Another guy I noticed in his 2000 wasa getting about 22mpg. He had 35s levaling kit bigger injectors and a edge comp box or what ever it is called. I was just thinking about putting 150hp injectors in my 02 cause I heard it will help with millage but I got a warranty from the dealer for 5 years so i may have to wait. Also I did see an improvement when i bought my truck in January I was getting 11mpg then. Got a superchips tuner for cheap and seen my mileage jump to 14 then I got a straight pipe 4in I jumped to16. Also I found out my fuel gauge is off at 1/4tnk I'm empty so idk if this affects my average reading on the gauge

I get 22 on hwy level 3 and fuel on 5

boost leak? dragging brake?

you can use new tranny fluid as a lube I run a lot of used power steering and tranny fluid in my fuel like 12 gals or so at a time its filter then goes into my ttruck I have a fass twin set up so it gets filtered good it does smell like shit and blows white smoke at idle if you run it right its not bad I do about 70% tranny and 30% fuel in summer does good!

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my brothers 06 auto with edge ez was getting 24 on highway!!!! with 4 inch straight pipe stock filter and 33s with 20inch rims