vehicle fuel milages

[circleTfarm]

I read where everyones diesels get 18 to 20+ mpg ,,how we have 2004 6.0L psd. and all we get is 13 to 14 in town or on trip.. whats the trick to good mpg.. /forums/images/graemlins/tongue.gif

 

[Charlie_in_TX]

I can't speak for anyone elses truck. I have a 'o4 PSD in a 2 wheel drive crew cab F250. I have gotten as much as 22 mph at 60 mph. I hate driving at 60. It drops to 18-19 at 70-75 mph. Closer to normal driving. Put a little scrap of a utility trailer (less than 2000lbs) and it drops into the 13s at the same speed. Tandem towing 2 of these trailers and I get the same milage. Seems like adding a little load drops my milage alot. Adding more only drops it a little.

 

[CTyler]

I know that it took a while for the the milage to come up on my stepsons powerstroke. He was getting about 15 maybe 16 when new. My coworker said his was 14-15 before it came up.
It may take 10-30k before it does.

 

[hudr]

All of the diesels we have owned needed some "break in" time before the mileage improved. Most of them also used a little oil for the first several thousand miles. But I am like you, I have never seen the high side of 20 w/ my 95 Chevy 6.5TD. Best I have ever gotten is 19 but knocking around here it averages about 15 to 16. My dad's old 86 Ford 6.9 averaged about 16 I think. We had a string of 6.2's that regularly got 22 to 25 MPG but that was in the 80's before the diesel "horsepower wars". I would rather have a more efficient engine and more gears myself. Most of these trucks will already pull more than they can stop anyway.

 

[Av8r3400]

Having driven only diesels for many years, now I can say the best way to get good milage with them is to stay out of the loud peddel.

My Cummins ('94 4x4 5speed) the fuel milage drops off dramatically at anything over 55mph. If I set the cruise at 55, it will get 20-21, if I set to 60, about 17, at 70 it will drop to 15 or less. Someone, 'somwhere else' computed that on his Cummins, 45mph would get the best milage (around 26mpg).

If I stay below 60mph with my old VW(1.6L diesel), it will get near 47mpg, but at 70 it drops to 38mpg.

/forums/images/graemlins/blush.gif

 

[runningbird]

My milage has always gone up after about 15k, on our old dodge 94 2wd we get 20 in town, 25 on the road and 20 on the road pulling 4 horses..on our newer 98 24v 4wd I get 17 in town, 19 on the road but only 13 pulling..the old cummins 12 valve is much more effecient IMO.

 

[circleTfarm]

we have about 22,000 on it now when it was purchased we brought it back from pa. to ohio about 4hour trip we got almost 20mpg when it was new, now we can't get over 14 on trip. seems the more miles we put on it the worse it gets ..would a fuel additive help?

 

[hudr]

what is the truck geared (rear end ratio)? The lower the RPM on a diesel the more effecient it is, usually, as a diesel generally makes more low end power. Those old 6.2s we had were geared about 3.23 or maybe 3.55. Most of the late model stuff is 4.10 or 4.11. I know my truck does much better at 60MPH(about 2000RPM) than it does at 70MPH (about 2500 RPM). I would really like to have a little taller gear in the rear end and more gears in the tranny, like a 6 or even 7 speed.

 

[CTyler]

I suppose it couldn't hurt however it sounds as though something may be wrong to drop that much milage. Not sure what to tell you I'm not a deisel guru. Is the air filter plugged up?

 

[runningbird]

check the air and fuel filter. Does the truck make more smoke than when your first bought it? also check your intercooler hoses and clamps. Do you have gauges on the truck. boost, pyro, fuel pressure? these things will help us help you.
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