Engine/Transmission (1994 - 1998) MPG check....

[The patriot]

I drove from s NJ to waterville , me.
Did a little driving around there before filling up. My odometer said exactly 510 miles, however I have 265's in place of the factory 245's so I'm sure it's 520-530 miles in reality. Maybe a little more.
Anyhow, using the 510 miles, I got 18.8 MPG's I've driven there several times over the years and this appears to be the best I've done. I DID bump the timing last summer.
Is this decent? I dont drive much anymore, so I havent filled up in a while other than filling it just before leaving.
I did a steady 72-77 (sometimes a bit more :-laf ) with the cruise on. This is going by the GPS.
It was full of stuff, but in reality everything I brought couldnt weigh 250 lbs.
I didnt drive crazy, but I wasnt ***** footing either. There was several full throttle blasts....to clean her out.:-laf One to 100 mph.
Is this decent MPG's?
I know if I drove like my Dad 19 would have been no problem.
I DEFINITELY did better on the way home, but I dont think I'll be fueling it up any time soon.
1998 12v qc 4x4 3.55's 265 tires, stock except 370 injectors and a BHAF. Timing @ around 17.5. (it dont like cold anymore, I'm guessing this is the reason)

 

[Missouri Mule]

Sounds reasonable to me.

 

[MLee]

For tire difference figure 1.06 on the mileage run. you will run just a little further, than with the 245's. What style tires are you running? street or traction, and tire pressure. I think you should do better than that. Mine will do @ that speed just under 22. mine is stock with 15.5 advance and Micheline's.

 

[The patriot]

Theyre Michelins, idk what exact model. LTX something other. It's dark out now. Havent checked them in a while...maybe 70 psi? IDK.
I have a UTE bumper, I KNOW I lost some mpg's from that. It's very big and very un aerodynamic. Aluminum, but HEAVY! It's responsible for the demise of no less than 2 mini vans.:laf
I was over 2200 much of the time. Maybe I should cut the timing back a bit.

 

[fest3er]

510 miles x 265/245 = 551.6 miles.

18.8 MPG x 265/245 = 20.3 MPG; 18.8 MPG x 551.6/510 = 20.3 MPG. Not too unreasonable for 17.5° timing. Especially if it's a manual trans. I occasionally get 19.5 with my '98 (auto trans); I could swear I got 20.8 once driving down to Ft. Bragg last year, with extra cetane boost in the fuel.

 

[fest3er]

510 miles x 265/245 = 551.6 miles.

18.8 MPG x 265/245 = 20.3 MPG; 18.8 MPG x 551.6/510 = 20.3 MPG. Not too unreasonable for 17.5° timing. Especially if it's a manual trans. I occasionally get 19.5 with my '98 (auto trans); I could swear I got 20.8 once driving down to Ft. Bragg last year, with extra cetane boost in the fuel.

 

[The patriot]

20.3! Thank you! Yes it's a 5 speed.
It used to get 600mi a tank pretty regularly way back when. Before the BHAF, injectors, timing, UTE & bigger tires.
That wasnt really highway though. 50mph max. Factory 12 deg timing really shined there.

 

[mwilson]

That's good mileage, I wouldn't touch a thing.

Your fuel is better than the Maine stuff BTW. I will jump a solid 2 mpg with the Mega the first time that I fuel out of state, typically beginning with a fill up in Connecticut and a second fill up in Southern Jersey. Happens every time I go out of state. I have hit a solid 21 mpg hand calculated before with the '06 on non-Maine fuel. Go figure......

 

[MLee]

The auto's have a few higher numbers in the finale drive. Like ours is a .72 and the auto is a .69, some thing like that because of the torque converter's lock up I think. Any thing over 21 is good for these trucks look at there age and the weight were packing. I still get better than a friend of mine when we are towing and traveling together and he has a Duramax and a 6 speed auto and a lighter trailer than mine. Just enjoy the ride.
"Rattly engine---12 valve they are, the sound of power"

 

[The patriot]

That's good mileage, I wouldn't touch a thing.

Your fuel is better than the Maine stuff BTW. I will jump a solid 2 mpg with the Mega the first time that I fuel out of state, typically beginning with a fill up in Connecticut and a second fill up in Southern Jersey. Happens every time I go out of state. I have hit a solid 21 mpg hand calculated before with the '06 on non-Maine fuel. Go figure......

I purposely did NOT speak of my so called fuel.:laf:

That's hard to tell if it's just the fuel or the way the nozzle fills the tank....IMO

 

[The patriot]

The auto's have a few higher numbers in the finale drive. Like ours is a .72 and the auto is a .69, some thing like that because of the torque converter's lock up I think. Any thing over 21 is good for these trucks look at there age and the weight were packing. I still get better than a friend of mine when we are towing and traveling together and he has a Duramax and a 6 speed auto and a lighter trailer than mine. Just enjoy the ride.
"Rattly engine---12 valve they are, the sound of power"

Last I weighed the truck, it weighed right around 10K full of fuel.

 

[The patriot]

Come to think of it, I fueled at shell (dead river) in Waterville and it seems as though I did better on the way back. I didnt fill it (I stuck the bed tank when I arrived here) and I have more here than I had there before filling.
The fuel that was in there before I left was "free fuel" I got from boaters that lost their boats in the Sandy storm.
I let it settle a good long time, and there was some squirmy stuff in the bottom of the can I didnt use.
I have an Fleetguard FL1000 as my "primary" filter, and the bowl is still clean.
I most likley would have done better if I used a fuel of quality. The only additive I remember being in there was I added about 1oz/gal of 2 stroke oil. That's it!

 

[LandShark]

Just did a cross country trip (FL to WA) and averaged 22.22 mpg, driving mostly 65 to 70 mph. Not bad for a 7000#, 20 year old truck with 250,000+ miles. I'm running all synthetic lubes, which may help a bit.

 

[The patriot]

22.22 is impressive indeed!
I may or may not have done better @ 65-70 mph.
My timing is bumped up pretty far, so I dont know if the lower speed would have necessarily helped much.
I'm running synthetics too except rotella 15w-40 in the engine.

 

[CharlieFoxtrot]

Last I weighed the truck, it weighed right around 10K full of fuel.

10K!?!?!? Is that in metric? Or with a full bed? Or a dually? Mine's a 2wd, but that's gotta be less than 1000LB difference. Mine's an auto, which is probably a smidge heavier than a manual, and mine's a club cab, which is probably a smidge lighter than a quad. Anyway, with my 400LB topper and my 250LB self, and a mostly full tank, mine weighs 6600. Even if yours is a dually, I can't see how it's 3400LB heavier than mine.

Anyway, I'd be pretty damn happy with that MPG. I have to do 65MPH or less to get that. Which happened exactly once, the day I bought it.

later
kevin

 

[The patriot]

Yup. 10,000 lbs. On a certified scrapyard scale.
I have a bed toolbox which is pretty full, and a 60 gallon transfer flow which was full. It's a 98 quad cab 2500 4x4 manual with a 8' fiberglass cap on the bed. The factory tank was also full.
Oh yea, I have a UTE bumper. It's aluminum, but substantially more weight than the factory. No winch.

FWIW someone asked which Michelins I was running. Theyre XC LT4's.

 

[CharlieFoxtrot]

Ah... With 700+ lb of fuel tank, ~400lb of cap, a few hundred lb of tool box, and the other differences, that's much less shocking. And that makes your fuel mileage even more impressive. I don't know why my truck does so much worse than many others.

 

[The patriot]

Mine did 20+ regularly around here & going back & forth to work. That was stock timing, 50 mph tops and 3 or 4 stop lights.
As soon as I went on the highway, I'd lose 3-5. More as I drove faster.
Towing the travel trailer I got about 13 or 14, but it was on the highway going much faster than I should. I tow very little. It's been several years now. This was before I bumped the timing too. May be a bit better now. The TT put me right about at max GVW.

 

[The patriot]

I just made another trip to my parents house.
I intentionally kept it at around 2100 rpm and I did NOT try to smoke any ricers. Bumped 2250 a couple times. It's inevitable.
Never hit a top speed of 90++ something (like last trip), and for all purposes drove "normally". NO full throttle bursts!
Netted 18.1 uncorrected for tires. Corrected for tires is about 19.72~ish.
Guess I may be dropping the timing back a little sometime in the future. It doesn't like cold weather starts like this anyway. I plan on throwing some new contacts on the ol starter to see if it helps.
I still havent checked the pressure. I usually don't bother with such things unless one looks low....or I plan on hauling something. Which is seldom.
I used the silver bottle of Power service "diesel clean". As per directions.

 

[The patriot]

Adjusted valves. They were wayyyy outta spec. It's an entirely different truck!
Checked tire pressure. 60 psi.!
I have no plans to go up that way this year, but I'm sure I'll get another 1-1.5 MPG's after these changes!