Hi all
Just to introduce myself, I'm a mechanic in the Canadian Military, Based in Edmonton Alberta. Most of my experience is with the 6V53 and 8.2. I also swapped a toyota diesel (1985) into a 91 4runner, That turns heads when folks hear the turbo whistling and a diesel humming under the hood.

I have a question on mileage I recently bought a 98 2500 E-Cab 4x4. it has 440,000Kms on the body and about 300,000Kms on the engine. I believe it to have 3.73 gearing, combined mileage appears to be around the 18-20MPG:( or 80 liters of fuel to 580Kms, this seems kinda thirsty to me, hell gas trucks get this kind of mileage.
It seems to have good power, can be started without waiting for the G plugs. I have changed a boost sensor, new filters (oil, fuel & Air). I've heard from two other guys I know who are getting between 25 and 28MPG. (800-1000K to a fill up) in 93(2500) & 96(3500) trucks. Power is nice but for what I use the truck for mileage is more important.
So does timing affect the mileage much? Also on start up it seems to "Clack loudly" until warm then it quiets down to a "won't wake the neighbours rattle"
I do have a Snap-on MT2500 scanner, and can get my hands on a Tech2 if I really need to.

Any hints would be welcomed.

Nick

A bigger exhaust with an advance the timing and higher than stock boost levels will increase your milage. Look in the glove box for RPO codes and look for it along with the best power/economy stratgy in the FAQ area.

18-20MPG or 80 liters of fuel to 580Kms
580 km = 360 miles
80 liter = 21 gallons

360/21 = 17MPG

Honestly, thats not that bad at all for an engine with 440,000k (273,000 miles).

Fuel conditioner arguably can improve mileage, make sure you get one with lubricity improver and cetane improver.

Exhaust upgrades certainly help all around.

What size tires are you running? If they're 245s, I would go 265, but first make sure they're all at rated pressure.

As far as timing, Electronic DS pumps don't function the way your used to with Bosch VE or any other mechanical pumps. Advancing the pump won't advance your timing, and if you go too far, you'll trip a TDC Offset code.

If they injectors are original or unknown, I would suggest replacement with that many miles.

Timing chain is stretched no doubt, and past due for replacement.

Sounds like my truck. I got a '98 Chevy K2500, ext cab, long bed, 6.5TD, w/3.73 limited slip. I average anywhere from 17.5 to 17.8 mpg. If I put her on the interstate and only run 70mph I'll get 18 to 18.2 mpg. If I hook my 20' bass boat behind her I get about 17.0 mpg.

The only difference is mine's only got 91K miles on the truck and original everything (except filters and a IP around 50K). I'm also shoed with 245 Michelin AT's at about 60psi.
Good Luck, but I hope you've not got any problems since mine sounds to be identical to yours.

hello neighbor! I'm over in Sherwood Park. Your numbers don't sound too far out. Considering its "mixed" driving, your city mileage hurts a bit. My mileage is right around there in the city. On the highway (no wind -- 100 km/h or 60 mph strictly), I can get 20 miles per US gallon (~24-25 miles per imperial gallon). Some of this mileage, as stated by others, was due in part to an opened up exhaust system.
I see it quite difficult to get 28 mpg. I don't know how your friend did it but i'd sure like to know;) One reason for their higher range is their fuel tank size. The long-boxes are equipped with 128 Litre tanks. I know gassers are much harder on fuel than that. My uncle has a 1995 gmc w/ a 350 (same 98 litre tank) and he was quite surprised that I could get 650+ km on a tank.

What does that 1985 Toyota diesel give you for mileage? Then take into account that your truck is 2000 lbs heavier and loaded with 6.5 litres of displacement. You'll appreciate the towing power (even though its not the new diesel available today)

howdy, i gotta 98 dually with a 9 1/2 ft. kodiak camper and i get 16.28 canadian gallons per mile. in the city. the truck has 152 k kilometers on it with a brand new under warranty injection pump. all in all i'm looking forward to finding out how many mile per gallons towing a 2000 pound boat from vancouver to the okanogan lake this summer.

What size tires are you running? If they're 245s, I would go 265, but first make sure they're all at rated pressure.

Better yet, go to 255/85/16 tires. Bigger diameter and less weight and resistance.

Hi Neighbour, I'm off of Victoria Trail, And would be interested to have a look at your exhaust mods. How much gain did you see from upgrading your exhaust to 3inch, or a better question would be was it worth the effort?
My friend claims 1000K to the tank on his 93 SB @100Kph,(hi-way)He has no reason to embellish. According to the above posts I may have been doing the math wrong for my truck I divided the Liters at 4.5 to get gallons and used 1.6 to convert from Kms to Miles. Still I do think it sucks a little too much dino,I guess I'll learn to live with it. Thanks for the input folks, I'll have to give your suggestions a go.
I just put in a 3 gauge pillar last night and the boost is hooked up, and the wires are run for the tranny & EGT, just gotta drill the manifold (as per sticky) and drill the tranny pan or mount it in the tranny cooler line. then I'm ready for mods, has anyone tried to use a waste gate from like a Toyota or other turbo that is boost operated? After reading some posts I think the boost sensor can be left plugged in, and a bracket made quite easily to hold the waste gate in place, with this type of WG you could adjust the Max psi to what ever you need/want....
Thanks for all the ideas!
Nick

My 96 3500 crew 4x4 gets about 16 - 16.5 mpg on the highway (4.10's and 235/85-R16's). Just FYI I've got two buddies I work with who have newer 2500 (03 and 04) gas 4x4 extra cabs w/ the 6.0l and they get around 14mpg on the highway. My wifes 98 1500 4x4 suburban w/ 5.7l gas gets 16-17mpg on the hwy. 18+- seems spot on for 3.73's to me.

I got 820 miles out of a tank on a trip quite a few years ago. 42 gallon tank

Better yet, go to 255/85/16 tires. Bigger diameter and less weight and resistance.

I run 265/70/16 but I will be going to 285 next tire change.
Right now with my 4.10's I'm smiling wide if I get 16 MPG ):h

So it sounds like I should be very happy to be getting 18MPG, as it could be much worse according to all the folks who have posted. I guess it is a bit of a shock when your used to 50MPG in a VW Jetta.Thanks all!

BTW this is an excellent forum, and resourse.
Nick

I see the problem......you've got the Jetta in the back of your truck, don't you?!:lol: Seriously, your mpg doesn't seem that far off. Try the suggestions made by others here and it may help some. You have to keep in mind, you are driving a big heavy brick down the road now, not a little toy car.:joke:

I get 15 mpg....any suggestions?:cool:

I get 15 mpg....any suggestions?:cool:

average? what's your gearing?

15 average for me. 3.73:1 but 103K on injectors and timing chain....

12.5 around town, 15.5 on the highway, 9-11 towing 8,000 lb. 214,000 miles don't know if the injectors are original or not, same with the timing chain.

Show me a full size, V8 gasser that gets "18-20" MPG anywhere but the window sticker. VERY few get into the high teens, and only if driven by someone with the throttle foot of a saint.

Most 454 owners are happy to get into double digits, most 350s run in the mid teens at best and the new Vortecs are just as thirsty.


Tim

When the 6.5s first came out, I remember a couple customers bragging about 24+ MPG, that was with 1/2ton, 2wd, 2 door trucks, 3.42 rearends though.
4wd, ext cab, long bed all add weight, and higher gear ratios means higher engine RPMs and all equal higher fuel consumption.

Go here for mileage stats. WWW.fueleconomy.gov (http://www.fueleconomy.gov/)

Or here for 4x4 mileage http://www.fueleconomy.gov/feg/findacar.htm

nickg, I think the exhaust system is worth it (3" at the minimum). Most importantly your downpipe from the turbo as it may be quite restrictive. Some seem to be bent up worse than others. Mine wasn't all that bad but some look like they were run over by a truck.

As stated in my sig below, mine is a 3" mandrel bent system with no cat and the muffler is straight-through so its basically a straight pipe except the loud rap at high rpm is muffled. The sound is great as it has a nice rumble and I can hear the turbo nicely whistle as it unspools when i let off the accelerator. As for performance, you don't notice much of a change when accelerating but the turbo spools faster when you punch the pedal. I bet it has lowered my EGT's but this is not proven since I didn't get gauges until after the exhaust system was installed.

I do believe I picked up 1 or 2 miles/gallon with the system because recently, i went on a trip where I filled up the neck in Hinton, drove to Jasper, down highway 93 to Banff, up to the Banff hot springs, drove to Radium and finally landed at a fuel station in Windemere (~10 km from Fairmont Hot Springs). I probably averaged 100 km/h and had 5 adults in the cab with about 400lbs of camp gear. I actually weighed the truck at a weight scale near Edson and came in at ~3400 kg (7500 lbs). At the Windemere diesel pump I put in 60.5L on 541.7 km (15.98 US gallons on 336.6 miles -- 21.06 miles/gallon) That's the best I've ever seen with this truck.

Wow I'd be happy with getting 9k to the liter at that rate you could easily squeeze 800K out of 90L of diesel... My math must be out to lunch as this is how I fiqured it out.
541.7(km) divided by 60.5(L)= 8.9 x 4.5(liters per gallon)=40.2 (Kms to the gallon) divided by 1.6= 25.1 MPG

I filled up today I had gone 546K and it took 86L or 67$ to fill up. And doing math my way (likely the wrong way) I get 17.8 MPG (50% hiway 50% city)
No matter how the math is done it wont change anything, I'm going to check my timing, free up the exhaust and see how it goes from there.
Nick

On another note I thought 7psi was normal for a 6.5 turbo, my gauge shows 13-14psi under a hard punch then it drops off but at each of the gear changes it jumps back up to 13-14psi. under 1/2 throttle it will hold a solid 10psi. boost thru all the gear changes. My buddys truck was hard pressed to get 5psi and you had to hold it hard just to get it.

Here is a calculator to make things easier.
http://www.euronet.nl/users/grantm/frans/fuel.html
Just enter the known values (liters and KMs and then click the derive button for the top section. It should give you MPG (both US and Imperial), kilometers per liter and liters per 100 KM.

I use "Lucas Upper Cylinder Lubricant" with injector cleaners and conditioners in it. Now I get about 900 Kms Per Fill up of 116 Litres!
I used to get about 700 - 750Kms per tank before using this stuff. It mustve cleaned my injectors or something because Ive got great mileage. My truck currently has 325,000 Kms on the engine. I bought the truck with 240,000 on it and I havent changed the injectors and Im not sure if or when they where changed.

Nick

On another note I thought 7psi was normal for a 6.5 turbo, my gauge shows 13-14psi under a hard punch then it drops off but at each of the gear changes it jumps back up to 13-14psi. under 1/2 throttle it will hold a solid 10psi. boost thru all the gear changes. My buddys truck was hard pressed to get 5psi and you had to hold it hard just to get it.

not being able to get over 5 psi finally convinced me to get rid of the vacuum pump and make an adjustable spring loaded unit. It has been a worry free operation since. I spend all the extra time I'm not trying to figure out boost problems answering these questions, LOL.

Very nice converter whatnot! A really good time saver. Its accurate as it compares with my manual calculations (not that i'm really good with math though). nickg, i must insist that this was strictly highway driving. As soon as I start driving in the city, my mileage goes in the tank.

As for your truck, it sounds like your boost is pumped up over mine. Did the boost increase for the newer than 95' trucks?? I know the GM-8 showed up after mine but do those allow spikes to 13 or 14 psi and a steady 10?? Mine spikes to 10 and gets cut back to 6.

Here's another really good conversion site, they have EVERYTHING!
www.onlineconversion.com

Did a 300 Km's trip today hauling 3000 lbs of brick in the back, cruise control set at 120 km's most of the way, topped up the tank when I got home at 37.4 Litres, don't know if it makes a difference to my mileage but I always add Howes diesel conditioner plus on every fill.