MILEAGE STILL stinks

[2shus]

I have done everything under the sun to increase my mileage and it seems that nothing has helped. No muffler&cat. New fuel filter and prefilter. (I) adjusted the valves about a month ago and it (seemed) like it helped for a tank or two but now in the dumper again. The truck runs good and is getting about 14. 5 MPG at 90% HWY driving and 10% in town. I talked to scheid diesel and they said it needed a (tune up) that includes the following: Pull pump and calibrate, check and set timing, adjust wastegate, adjust valves (again), pull injectors and clean & etc all at a cost of about $7-900. 00. That is a chunk of change!! I can't spend that kind of money unless i am positive that it needs it and also the diesel place is a long way from me and they want the truck for a day and a half. Their is a cummins place nearby me also. What if any of these do i really need to do? Can i adjust or set the timing myself? (Never done it on a diesel) Does the pump really need pulled and calibrated? I have ran injector cleaner on a regular basis so do the injectors really need pulled? I would be tempted to pull the injectors myself but don't know what bad things to look for. Don't know where the wastegate is or what to look for on adjustment of it? The calibrating of the pump sounds way over my head. The truck had about 100,000 miles on it when i got it and now has about 113,000 and i have no history other than what i have done to it myself, (valve adj. ,kill cat&muffler, filter change) I have done no towing. It is frustrating to hear about everyone getting 20-23 MPG and i would hate to lay that kind of money down with no improvement in MPG. Anyone have real advice??

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1995 Dodge 2500 SLT Reg. cab 4x4 Auto,Long Bed 12 valve, 3. 5 rears, K&N Air filter 112,000 miles Anti lock brk sys, 305/70-16/Mickey Thompson Alum. wheels,Leer cap, Nerf Bars, Black/Black C/D Player Overload springs, Reese Hitch, T. C. Lockup switch, Cats dead, straight pipe.

 

[SlyBones]

Is your odometer accurate with those large tires, are you properly compensating for the mileage with the larger tires.

245/75-16 are 30. 4 inches. My 285/75-16 are 32. 8 inches. You need to add 8% to go from 30. 4 to 32. 8 -- So when I calc mileage I take my mileage and add 8%, then divide by the # of gallons.



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1997 2500 4x4, CC, Auto, 3. 54 LSD, 66K, Everything inc Leather, K&N, 4" BD cat-back, otherwise stock, Isspro Gauges(3), 285/75/16 on Alcola's, RS9000's, Canopy, BedLiner, and tons more.

 

[2shus]

Hi, the tires and rims were on it when i got it and it came with the extra factory wheels. Also i have had the speedo checked twice and clocked so someone must have changed the speedo gear. I don't really care for the monster truck look either and it makes it to hard work out of or haul anything in the back end. I have always been told that bigger tires would increase MPG. Also i don't think it has a lift kit on it but i could be wrong. Finally if i buy new tires what size should i run to increase MPG, i don't do offroading?

[/b][/QUOTE]

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1995 Dodge 2500 SLT Reg. cab 4x4 Auto,Long Bed 12 valve, 3. 5 rears, K&N Air filter 112,000 miles Anti lock brk sys, 305/70-16/Mickey Thompson Alum. wheels,Leer cap, Nerf Bars, Black/Black C/D Player Overload springs, Reese Hitch, T. C. Lockup switch, Cats dead, straight pipe.

[This message has been edited by 2shus (edited 04-01-2001). ]

[This message has been edited by 2shus (edited 04-01-2001). ]

 

[The patriot]

I'd put the stock tires/rims back on it, re check the speedo, then try a few tanks through it.

In theory, bigger (larger overall diameter) will help in MPG's, but it seems like out trucks are properly geared from the factory, so it hasnt made a noticable improvement.
You have the 305's. The inc. diameter is offset by added rolling resistance of the wide tires. Rolling resistance= less MPG's.
Eric

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98 Quad cab 4X4 2500 12 valve,5 speed,3. 54 rears, 8' bed. Michelin 265 75 16 lr-E. Boost and egt gauges but basicly stock except for a "properly adjusted" AFC. Cat in the garage. Uniden HR 2510, Texas Star 1200 amp. 63,000 Mi as of 1/27/01.
NRA life member. High power/IDPA.

 

[2shus]

What size tires should i run, the tires on my factory rims are 245-16's but they are no good.

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1995 Dodge 2500 SLT Reg. cab 4x4 Auto,Long Bed 12 valve, 3. 5 rears, K&N Air filter 112,000 miles Anti lock brk sys, 305/70-16/Mickey Thompson Alum. wheels,Leer cap, Nerf Bars, Black/Black C/D Player Overload springs, Reese Hitch, T. C. Lockup switch, Cats dead, straight pipe.

 

[RColston]

2SHUS,

The 235/85 Michelin tires available from that #ad
really big club store have worked great for me. Just turned the 80k mark and this is the first replacements on the truck since the original junk 245/75's. Replaced'em at about 25k and the Mich's are still with about 30% orig. tread front and rear. My mileage seems pretty constant at 24-25 empty, 12-13 pulling the 13K 5er. I think the 5spd's generally get better milage than the auto's. Certainly doesent make'em bad though #ad
. As you can see mine is still stock, FOR NOW.

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1996,2500,CC,SLT,Driftwoodx2,2wd,5spd. ,3. 54,K&N,AirRide,Reese20k,1996 Hitchhiker,36RK 2slide pretty stock, but lookin' for more!

 

[SlyBones]

Another thought, what kind of fuel you running. I heard around there that you can get several MPG diff between good quality fuel and the bad stuff. I just switched. Ran BrandA for 7mo. Second tank on BrandB. Too soon to tell.

Best I have ever gotten is 21. 5. Remember 2x4 gets better than 4x4, 5sp better than auto, 2500 std cab short box, better than 3500 quad cab long box, 3. 54 better than 4. 10, flat terrain better than hilly terrain, etc.

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1997 2500 4x4, CC, Auto, 3. 54 LSD, 66K, Everything inc Leather, K&N, 4" BD cat-back, otherwise stock, Isspro Gauges(3), 285/75/16 on Alcola's, RS9000's, Canopy, BedLiner, and tons more.

 

[2shus]

I took care of the tire question about them being to wide or big, i went this afternoon and bought a new set of LT 265/75-16's and had them mounted on my factory rims. It will be interesting to see my mileage from now on. Now it seems my speedo is off for sure. I think it shows that i am going a lot faster than i actually am, guess i will have to change the little gear in the transmission. Thanks for all your replys and help.

 

[Missouri Mule]

2shus,
Pump timing probably wouldn't hurt(pump timed to engine). Yes you could, but better to let someone with experience do it. Pulling and calibrating ?
Have you done fuel pressure test?
I think if your having problems gauges a must.
Have you checked to see if any bombing was done?
How heavy and big is Leer cap?
Locking fuel cap. Check for leaks; engine to fuel tank.
I agree mileage to low. But don't expect 22-23 mpg expect 18-20 mpg.
Your wastegate is located at turbo exhuast housing. It is pressure activated and controls max boost so that components wont't fail. The wastegate is set by factoroy at around 18 to 20 psi it can be adjusted to 30 psi safely but having boost gauge is a must.
You have to set up regulated air pressure(air compressor/hose with adjustable dial) to it than adjust linkage(short form).

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Bill Thomas
Missouri Mule - 96 Wht 4X4 ST CC,5 spd, 3. 54, 8 ft bed, 1 ft high cheater boards.
99 Freightliner bl/wht FL60 ISB-5. 9 24v,215 hp,520 tq,6 spd, 3. 59 nsr,16 ft box, 19. 5 tires,Wt/gvw 11,000/23000

 

[The patriot]

2shus, hope you got load range E.
I got those tires. Michelins. I like them.
Eric

 

[Extreme1]

I FOUND YOUR MILAGE PROBLEM!!!!

Tires, my friend! Do a search on lift kits. Recently a question was posted on them and a few guys posted pictures of their trucks. The thread wandered a bit (NOT on the TDR site!) and I asked what kind of milage they were getting.

You are actually doning really GOOD, believe it or not. I was considering the monster truck look but didn't want to sacrifice milage that much. As it is, I noticed about a 1 1/2-2 mpg drop when I added my 235's.

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'94 3500 4x4, 210,000 miles, Never had a cat, Auto w/shift kit (thanks Dave G), 3. 54 Gears, TST #5 plate, 235-85-16s, Rancho 9000s w/remote, Isspro Gauges & Amsoil Air, Oil & Bypass Filters & Lubes, AWOL intake boot.
Punchlist: X-Mount Mirrors, 14 cm Turbo Housing & 215 Injectors.
NRA member.
Blue Ribbon Coalition member.
"Warrantee? We don't need no stinking warrantee!"

[This message has been edited by Extreme1 (edited 04-01-2001). ]

 

[Iceman1]

I tend to agree. What looks good can sacrifice something on the flip side. What you might do is max out the air recommendation per tire. That would decrease the rolling resistance but make the ride rough... Another thing I have seen is that bug screens can drop the mpg by at least a mile per gallon. Just a thought. .

[This message has been edited by Iceman (edited 04-01-2001). ]

 

[Bud Fox]

2shus read my post if you get a chance THANKS

 

[2shus]

After purchasing the new smaller tires on sunday i was on about a half of tank of fuel and i only drove a couple of miles before installing new speedometer gear to match my new tire size(265-16) and i can see a vast improvement allready. I filled up today and am anxious to see mileage after a full tank. I try to always drive moderately and keep RPM's under 2000. I will post after a tank or 2 with my results. Thanks to all who replied. D #ad
:

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1995 Dodge 2500 SLT Reg. cab 4x4 Auto,Long Bed 12 valve, 3. 5 rears, K&N Air filter 112,000 miles Anti lock brk sys, 305/70-16/Mickey Thompson Alum. wheels,Leer cap, Nerf Bars, Black/Black C/D Player Overload springs, Reese Hitch, T. C. Lockup switch, Cats dead, straight pipe.