Improving fuel mileage?

[camojcory]

Hey guys! well i'm all done giving my 1009 a tune up, but i'm still only getting around 14 mpg. Is there anything i can do to boost my mileage up to the 18-23 mpg i've heard members getting?

the truck is stock and i recently completed the following,

-doghead starter relay mod
-new 60g glow plugs and connectors
-new fuel filter
-oil change
-new batterys
-new glow plug relay
-new alternator belts
-new 31-10.5-15 goodyear wrangler silent armor tires
-1000 watt freeze plug block heater

i did not change the air cleaner because it looked brand new and one of the alternators was replaced just before i bought the truck.

i use this as a daily driver, in town and out. i probably drive with a slightly heavy foot but i dont drive it like i stole it. i have been adding fuel additives to the tank but only every other tank.

any suggestions or anything i missed to ease my pocket book a little at the pump?

 

[Nick Danger]

I'd check the brakes make sure they're not dragging ,calipers not stuck,
caliper pins greased. brake pads wearing evenly. front end alignment
all can make a big difference in fuel consumption....

 

[patracy]

I'd check pump timing and the delivery. If you're throwing out black smoke, the fuel is up too high.

The key to good mileage on a diesel is using the torque band and keeping EGT's low. I know your engine is a NA engine. But a good rule of thumb is to keep EGT's under 600F. It's a lot harder to do than some would think. On a turbo'ed engine, it's best to keep it under 600F and under 5psi of boost.

 

[kipman]

Mine had that problem, went from 20 to 14, rebuilt the pump and rebuilt the injectors, way more power and back to 20 mpg.

 

[wallew]

all motors are basically big air pumps...

the more air in and the more air out, GENERALLY SPEAKING means better mpg

Those twenty year old mufflers are not doubt in need of replacement - go with a three chamber free flow - and then replace your filter with a K&N...

I also did the old 'hot rod' trick of flipping the top of the air cleaner. Except you can't do this with the diesel. So I fabbed a flat plate that fits on top of the K&N. Cost was less than twenty bucks. A sheet of metal and one three inch wide strip of 1/4" aluminum.

 

[Barrman]

How fast are you going on the highway? Keep the engine below 2200 rpm and you should be around 20 mpg. Keep it below 2000 rpm and you should be up near 23 or more.

Measure your tires actual size and plug that into a ratio calculator to figure out what speed crosses over to the rpms mentioned. 60-65 mph is probably going to be the speed you want to keep it at or below.

If more air and slowing down don't help, start thinking pump and or injectors because that is all that is left.

 

[wallew]

Barrman,
right on the money.

that's WHY I LIKE these engines in these trucks - not much to actually break - and IF properly maintained and run within specs - they should give you another twenty - thirty years of service.

The key is proper maintenance and not abusing what you have. But it does take a lot to actuallly abuse one of these - remember these military trucks were driven by EVERYONE and not babied. And yet we still get years and years of service out of them.

GOD BLESS the military for standardizing everything. One of these days I might try and talk the little woman into adding a HMMWV IF they ever sell them as surplus umpteen years from now. Hopefully it will have the 6.5L, though to have one with it's original 6.2L is something I would love to see. Did they ever store any of these HMMWV's in those cave in NORWAY?

 

[camojcory]

thanks for the input guys!

i will have to take a look at the brakes. they don't feel or smell like they are dragging but the guy i bought it from said he replaced the front brakes and if he did the kind of job on the brakes like he did on the rest of the truck, i probably have problems there.

wallew, i am not familiar with the old 'hot rod' trick. can you explain this a little more and/or show some pictures?

does anyone know how much it would cost to replace the fuel pump and injectors?

 

[lindyp38]

Tire pressure....

Proper front end alignment....

Excess cargo.......

 

[wallew]

You DON'T need to replace the injectors...

Do an advanced search here on the CUCV portion of the forum for an 'Injector tip' change. I hate to admit it, but my mind is blank who posted it. But for about $100 you can replace the injector tips with the 6.2L MARINE injector tips and then replace the low pressure fuel return line as it will most likely crumble as you remove the injectors to replace the tips.

I'm going to be doing this next year to mine CUCV's. That is IF I see the small gains I'm hoping for. We will see.

And I will post the results here.

 

[1986Blazerk5]

I don't know if it is worth the gain but i have heard that putting a electric fan on and taking off the mechanical one will give you about 1-2 miles per gallon better. I don't know if this is true but it makes sense, less that the engine needs to turn