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Not pleased with mpg!!

4K views 76 replies 13 participants last post by  Canyon JYD 
#1 ·
I'm not too pleased with the mpg on my truck. I have not gone on a long trip yet. I do live 90 miles from nearest large city. When I fill up I'm full for 2 days. Is it possible short trips are to blame? I have only filled up at 3/4 twice, when I return to town. My numbers say 15.5 mpg. I notice you guys are advertising larger numbers than this. My truck is supposed to be stock. Last night a fellow who has been running dodge for a long time noticed something that I noticed as well, but thought it normal. When I fire up black smoke. When I get on it black smoke. I wrote it off to having straight pipe. Everything appears normal under the hood and even under the dash. He went right to checking things out. Is there a possible program in my computer? How can I tell? Also can a program reduce my mileage? If so any advice to remedy this situation would be GREATLY appreciated. I am interested in daily driving and long term dependability. As with any vehicle the most mph is the goal for economical reasons. I have looked into some programmers and they have different modes, fuel economy, towing, power. Does anyone know of a program that is put directly into the ECM? This is my first diesel, this is why I ask these questions. I am actually a mechanic by profession, just not on diesel.
 
#2 ·
I see 15.8 on my 55 mile round trip to work and back. That's half town and half freeway. I put an edge comp on mine thinking I would see a little better mileage but come to find out since the edge, I like to mash the skinny pedal more often. Still getting 15.7 but due to driver habits. I think I would see about 17 if I could keep off the throttle.
 
#3 ·
i have always blown smoke on start up and a very light haze when i matted on it...when was your last oil change? what kinda shape are your injectors in? what about fuel lines? air filter? I got 16.5 around town, now i get 19 around town w/ the Max Micro, and i went 400 miles interstate got 23!!!!! that was completly stock.

Nathaniel
 
#4 ·
The pedal is what I thought about thie first caculation. The next tank I actually babied it to see if there would be a difference. Though when I pass slow @$$*s I :grd . But that shouldn't account for that much. Thanks for the feed back. I don't feel so bad now. Kind of thought I was getting poor mileage. I would like to know if this is normal.
 
#6 ·
I should add that I drive about 5 miles 2-4 times a day at 15-35 mph. on roads that passing is not an option. I can only pass when going to town.
 
#8 ·
Yeah, I was going to ask about trans, tires and miles on the clock. It really comes down to driver. Also, I would go ahead and change all your fluids and especially your fuel and air filters. Those things being dirty will suck milage way down.

I usually get 16.5-18 around town, and 18-20 highway. both of those used to be around 2 mpg higher, but I think a slipping trans and shot converter are to blame for that.
Sean
 
#9 ·
The air filter is new and the oil is due in about 400 miles I'm told when bought. About 194 on the clock. Very well maintained truck. Don't know about the fuel filter. As to the light haze, compared to what I see some doing yes light describes it. But when you haze on each gear and leave a cloud on accelerating after a turn with moderate pedal that stays until you get 500-600 yds. down the road when the speed limit is 35 and don't exceed it, I question it now.
 
#10 ·
Yeah, that sounds like a box, programmer, or injectors. Something of that nature. Usually those mods do alright for increasing milage though, depending on what it is. Most Boxes and programmers change Parameters such as timing to help with power and throttle response and they also help out fuel economy. Injectors, it depends on the injectors, some help milage because of improved spray patterns, and others hurt it, because they just hone out the stock holes, making them bigger and lowering injection pressure.

Its hard to say what your truck has done to it, but it shouldn't put out much noticable smoke if its stock.

However, your altitude could have a bit of an effect on things too. I see your from the Grand Canyon area. I was down in Flagstaff a little over a year ago, and my truck smoked quite a bit down there, and it doesn't have that much done to it. Also, EGT's can get dangerously hot, real easy at altitude, I could peg 1800* no problem. I'm not sure how high you guys are, but I would look into getting a pyro ASAP, especially if your truck is smoking, you could be running really hot.
Sean
 
#11 ·
You also have to figure with 194K on the clock the sticks are probably getting worn which would acount for the smoke especially with it being a stick and haveing to build boost each gear. You are right with me though mileage wise.

andy
 
#12 ·
nattygasmech said:
235/85/16. 4x4 dually 5 speed, keeping the rpm b/t 12-2200.
Your mileage sounds pretty normal for a 4x4 dually. Reckon you have 4.10 gears, too.

I couldn't get over 16.1 mpg stock, and with the dually box. Went to a 10 plate, 370 injectors and a PDR HX40 turbo. Was getting 17.5 after that. :D

Now have a flatbed and the current mods. Also have 235s vs the stock 215 tires. Getting ~12-14mpg (uncorrected for tire size) now. Lost 2mpg with the bed swap alone. LOTS of dirty air. More than double stock power though. :sly:
 
#13 ·
sstockton said:
Injectors, it depends on the injectors, some help milage because of improved spray patterns, and others hurt it, because they just hone out the stock holes, making them bigger and lowering injection pressure.
Doubt the spray pattern was changed much, if at all. If done correctly, they should match the stock pattern.

Biggers holes will lower the pop off pressure, but the fuel shop is supposed to readjust the psi back to stock, or even a tad higher for good atomization. Big holes at lower psi will created larger droplets that don't atomize well. Makes a big difference. Smaller droplets burn more efficiently, with less smoke and generally lower EGTs.
 
#14 ·
I too am getting poopy mileage.

I'm only getting into the low 14's and it sucks. I've tried driving like Miss Daisy, driving normally, everything and I can't get these numbers you guy's get to save my life.

Do you think adding an Edge will help me out? I'm getting desperate.
 
#15 ·
Mayfair said:
I too am getting poopy mileage.

I'm only getting into the low 14's and it sucks. I've tried driving like Miss Daisy, driving normally, everything and I can't get these numbers you guy's get to save my life.

Do you think adding an Edge will help me out? I'm getting desperate.
Fill in your sig so we can see what you have first. Is your truck an auto or manual, how many miles?
 
#16 ·
A box with timing advance should help some.
 
#22 ·
jakebrake said:
What tires/size's? I'm getting about 20 on long freeway trips. Corse I haven't recalibrated for the larger tires yet.
Then I had 215 Goodyears on the front....and 235 Mich's L/MS on the back, but they had like 2% tread on them...that was about 4 weeks ago...now ive got 235 Courser A/Ts all the way around...

Nathaniel
 
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