fuel cost down, mileage down

[norm]

Filled up @ $1.759 today - in Elkton, MD where that's a good bit cheaper than gasoline. But, my mileage is not so good. Truck seems to be running fine - decent power, burns some oil, 109k on odo. I got 11 and change MPG this last tank and around 12 tank before that. I do not tow much with my truck, but it is my (HVAC) service truck at about 8700 lbs (crew cab, SRW, 8' Reading covered utility body with tools, supplies, and me).
Anyone have ideas on what to check, or is this mileage acceptable for my rig? Anyone else out there running a (heavy) service truck?

[tanker]

Hi Norm, I would think you should do better than 11mpg. My worse around town is about 13mpg w/3:73's and weigh about 6600lbs. You do have 4:10's and have another 2000lbs than most, but I would do a real test. First fill up at a known pump, until it shuts off by itself. Now run some miles, and return to the same pump and fill up the same way. This will/should keep things on the same playing field. You may also wish to alter your driving habits a little, check the filters, reduce idle time, use a fuel additive which will boost the cetane level for more power. I average about 14mpg all round except towing. Engine rpm's, load, wind etc. all play a big part in the economy. smile.gif

[markrinker]

My 1994 with 4.10s gets 10 whether empty or loaded. Just got done with a 700 mile thrash yesterday, one way was pulling 2,000# trailer loaded with 9,400# of aluminum bar stock, the other was empty. Same mileage, almost same speed on the hills. My average speed was around 65MPH for the entire trip, 75MPH on the flats, slower in the hills.

If I had the patience (and time) to average 55-60MPH instead, mileage would climb to a whopping 11 or 12. I opt to save time and waste fuel.

The funny thing is the biggest factor affecting my ability to run 70-75 down the interstate is headwind or tailwind, NOT load??!!!!!

[moondoggie]

Good Day!

Load primarily affects mpg when accelerating or going up a hill; wind resistance increases as the square of speed (double the speed, 4x the wind resistance). Going from 55 mph to 70 mph is about a 27% increase in speed, but a 62% increase in wind resistance. :mad:

Blessings!

Brian Johnson, #5044

[ssybert]

I've got a hell of a problem just GETTING to 75mph. Takes me a good 15 seconds from 65-75 with the pedal on the floor UNLOADED. I bought a comression tester to test the truck but it failed after 2 cylinders. Figures. It's got 100K on it and i'm going to do injectors regardless. All signs indicate the truck was as poorly maintained as it could have been. I'm sure the injectors got no special attention :-/

i'll get another compression gauge, but right now I need this truck to be able to keep up with traffic when I head to Canada next month.

[moondoggie]

Good Day!

Good indicators of good compression:
</font> no white smoke on start-up except on extremely cold days;</font> cranks &lt; 2 seconds on warm start with no significant smoke.</font>The pre-electronic pump motors were especially easy to test: on all of them I've ever owned, on warm start, you really can't release the key fast enough & the engine's running.

It's still a REALLY good idea to check compression when you don't know where your motor is.

If you haven't already done so, I'd definitely change air & fuel filters, & probably have at least one spare fuel filter on-hand.

Blessings!

Brian Johnson, #5044

[ssybert]

Don't mean to hijack this thread here... Was just commenting on my situation too. There is all kinds of smoke on start up in the morning. not cold.. maybe 55* - 65* F. After it starts, I can hear a cyninder NOT firing (is this the correct term?) correctly but sputtering. RPM's stay stable but the engine is not running on all 8. If It step on the gas I can hear the missing get fewer and farther between until it's gone... so is the smoke. I think the smoke is white...maybe a light blue? There's alot of it until the sputtering goes away. The power level is so bad the AC makes a HUGE impact on my acceleration. It means the difference between being able to only go 65 or shutting AC off, going 75.

I wish that damn guage didn't fail. Oh well.. would injectors be a good idea @104K anyway?

[jimcreek]

my truck gets 11 mpg at 13,000lbs 14ft box flat land here in S.C. U.S.A. I to have an A/C service truck.
I have a 96 service truck that isn't on the road yet need some one to put in it do you know anybody.