Poor mileage on 2001.5 ETH

[ROADWARRIOR]

My friend was considering a Cummins, Powerstroke, and a Dura-Pud. After talking to him, I convinced him that the Cummins was the wisest choice.

He loves his truck but today told me that his mileage has been getting worse. His first tank he got 16 solo, and since then he has been getting 14 solo and 12 pulling one horse. These figures are calculated by hand. Now I am starting to look like a dummy since fuel economy was one of my selling points.

I told him to see about a dealer reflash and possibly a bad IAT sensor. Do you guys have any other ideas?

His truck is a 3500 six speed 4x4 with 3. 54 gears. Please help me regain my integrity. One other note, he has 3500 miles and the temps. have been typically staying around 60. I told him about the engine break in, but I wouldn't think his mileage would be getting worse.



Thanks, Dan

 

[Mundgyver]

Question??? Did he just buy the truck?? How many miles?? Gearing?? I get 24. 2 with my rig if I drive safe and sane. If I put my foot to it at 70/75, I'm lookin at 18/19. All this is on the flat and level with no load. My trucks first tank got 18. 35 and then dipped to around 16. This was before the engine was broke in. It will come back.

 

[ROADWARRIOR]

He bought his truck with 500 miles on it. It is equiped with 3. 54 gears. He now has over 3500 miles on it. I know that it isn't broke in yet, I just thought it is strange that his first tank was 16 and now it has diminished to 14. He fuels up at the same truck stop everytime as well.

 

[Floor It]

I too started off with 16mpg and now with 16000miles my mpg on average has dropped. I've checked the IAT it was ok,had it at the dealer and to cummin's and no problems. In my opinion the new 24v sucks on mpg. Some peopleare getting good mpg but this new engine is too sensitive to things that cause bad mpg. IMO

 

[mikel]

Something ain't right

I think there's something wrong with your buddy's truck. I've just turned 5000 miles on mine and have gotten a high of 19. 67 empty and a low of 14. 35 pulling 8-9k. True, mine's a 2500 and your friend has a 3500, but I don't think that would explain all the difference. Oh yeah I generally drive about 75mph. If he's game, get it to Cummins and let the experts have a look at it. It will cost him out of pocket, but he'll be dealing with people that know the engine inside and out.



Good luck,

Mike

 

[Big White Beast]

That was my biggest complaint......

And I took mine to Cummins on a DC work order. Alls they did was Dyno it and tell me it was within DC's specs. I don't have a good feel about the Cummins shop out here. Don't think their main concern is Ram drivers.



Personally I feel some are better than others when it comes to mileage. Mine happens to be a pig. At least the EZ gave me 2 MPG and some power to work with. The 3500 also does make a big difference. Though stock and empty he should't be that low. After break in it should pick up some. Mine hasn't yet at 16K so I'm hoping I will see some change yet.



Just irks me that some people tow way more than I haul around daily and get 14 MPG and I'm lucky to get 12. 5.



Garrett

 

[Happy Camper]

18. 5 empty. 12 to 14 towing.

 

[wtrenholm]

I've run 4 tanks of fuel through my truck since delivery and my milage is not all that impressive either.



First tank was 15. 9 empty.

Second was 14. 9 with some very light hauling.

Third was 13. 2 pulling 7K, 275 miles at 75mph.

Fourth was 14. 5 pulling 5K, same trip at 70mph.



Not exactly wonderful but the truck is great. I guess I'll put some miles on before I get too excited. Probably gotta learn to drive mellow to get some decent mpg.



Glad to be part of the TDR,

Wayne

 

[Oasis-3]

It will get better after 20,000 miles My truck started out bad and getting better every day now at 22,000 miles After 10,000 miles drive it like you stold it Worked for me.

Good Luck

Cliff

 

[Ray Torresdal]

Poor mileage

Don't forget to check the clamps from turbo to intercooler to intake!!! Mine were all loose when I got my truck. Thanks to TDR, I checked them the first week. I've averaged 18. 25 for 61,000 miles driven in 18 months, mostly empty, but up to 24,500 GCW. My truck expense dropped in half, and I'm driving more miles. Ray

 

[F-15I Ra'am]

While tightening the intercooler hose clamps you might want to check the bottom left [driver's side] hose. On both my 2001 and my dad's 2001. 5,the sheet metal from the fender was digging into the side of it. It had'nt cut all the way through but eventually would have!

 

[Big White Beast]

All tight.....

Check em regularly. Changed IAT in slim hopes. Have been to the dealer (early on ) and the DRB read exactly what I calculated my mileage to be. Curious now if the EZ throws off that internal calc also.



With my 10K lb truck I would think it was broke in by now. But then I never baby it for mileage either. Dumbfounds me how anyone can drive that slow.



I know it takes roughly 8-10 pounds of boost just to do 75. Besides the weight the utility bed is a big sail. Catches all the wind.



My point is that some people tow 5er's and they can't be anymore aerodynamic and yet get better mileage. I'm just happy it aint a gasser as I would probably be getting 6 MPG.



Still hoping it will settle in with some more miles on her. Jsut changed the oil and going to do an analasys. Maybe that will reveal something.



Garrett

 

[HC]

My vote is to try the IAT. The part only costs about $22, and it is something that is on the same order of difficulty as changing one spark plug. Go to http://smokindiesel.com/Technical.htm for some good discussion, or to https://www.turbodieselregister.com/forums/showthread.php?s=&threadid=11618&highlight=intake+sensor for both discussion and further down in the thread, resistor specifications to check against.

This is a part that if the readings are off, mileage will suck, but there will most likely not be any codes set that tell the technicians there is a problem. So I say spend $22 and eliminate at least one possible cause.

My truck gets great mileage at 70 degrees, then will drop an mpg or two or gain the same amount according to whether or not the average temps are dipping into the 40's that week. I know the Flying J isn't switching back and forth from winter to summer fuel every week, so I'm suspecting the IAT and plan to replace it ASAIGATI. (As Soon As I Get Around To It)

 

[RonaldLarson]

Mileage

is a function of driving habits, weather, fuel cetane number, load, terrain and engine maintenance. It is also normal for the trucks to start out with high fuel mileage, then lose some as they start toward break-in. Your friend is experiencing some or all of the above, but my money is on driving habits. Because first time Cummins owners are used to neck snapping gasser acceleration, they tend to put their foot into it, when in fact they are moving much faster than they think. I was guilty of the same thing, untill I learned to look at the speedo, not the tach!

We had a guy come in this Monday complaining of "bad" mileage. We watched him drive from the street to our service drive in a cloud of black smoke. DUH!

Ron

 

[Bigsaint]

Winter blend

Is it possible that he started off with the summer fuel and then added winter mix after his initial tankfull ? I know we have switched to winter blend here, my mileage has dropped as well as performance, even with the Stan. PF added at every fill up.



Scott W.

 

[ralphr]

I have belonged to this forum for 2 years now. When I first joined people were saying you need to wait until the engine has broken in before getting a good milage figure. Well at 15K nothing at 20K, and even 30K nothing changed much, now she has turned 36K and I can say the engine has broke in! The actual milage when this happens will vary from use, (I don't trailer or haul much so I guess thats what took so long). Don't get discouredged, these are not your typical engines, the love to be driven and will give you years of service with proper maintenance.