I have a 2003 Excursion limited 4x4 with a 122,00km with the 6.0L, 20" 08 rims with 275 65 20,egr delete, blue spring,turbo update feed and drain tubes,bango bolts,new ball joints,relubed caliper pins[no dragging brakes].

I wanted to double check if my numbers seem to be good or bad because I think I should be getting better fuel milage then this.

10mpg city avg [try to light footed under 2000rpm's]

Just took a trip 5 hour trip,cruise control
12.4mpg avg hiway at just under 70/hr [mostly straight roads,little hills]
[said 15.4mpg avg on overhead]
184 ECT 191 EOT [didn't really change]
-10C outside
5 to 7 boost at 70/hr
Used CTS for all numbers

Is my temp's to low?

Is the 20" causing this much fuel loss?

There are also no codes
at half a tank just over 500km on trip counter

I also have tried matts SRL tune [non studded with similar results] took off tune for trip though and keeping tune off because there has to be something going on.

Anything I can check or ideas would be great! Thanks

 

Your tires are a bit wider than stock, which is more resistance. I'm running taller and wider tires (285/75) with Matt's srl+ (400rwhp) and getting better economy
Your engine and oil temps are fine.
Those boost numbers are good as long as your cruising not accelerating.
Give the 6.0L forum a try, you should see better economy than that. That sounds like a V10 for fuel!

 

Gonna move this over to the 6.0L PSD forum.

Stewart

 

Is this a new issue ?
I would check the tire pressure.

Sean

 

Also knowing what flash version your ficm has will help. I believe the newest flash from ford ( designed to reduce stictioni believe) lowered fuel economy an average of 1-2 mpg

 

Are you calculating regular gallons or imperial?

And is that miles/gallon or kilometers/gallon?

Numbers are extremely low for miles/gal

 

If you are not already start adding cetane boost, I use the motorcraft cetane boost, it also adds lubricity to the fuel. Also try hand calculating the mileage as it is more accurate.

 

I am running the latest flashes on stock tires - 265/70R-17 - and I can get 21 mpg cruising unloaded at 65 mph. But - if your cruise includes a cold start at -10C, ten minutes of idling to warm up, and your cruise was less than a full tank, then the mileage looks more normal. Cold starts in winter totally kill mileage. Stop and start driving, city driving kill mileage. Your tires are 36.25" in diameter, that will hurt stop and start mileage the worst, probably little effect on highway cruising.

 

Your mpg will be down 2-3 because of winter fuel. A mild tune on your ficm could net 2-1 mpg. Cetane booster & synthetic oil may help. Sticking brakes or drive train if this is a recent drop.

 

That's about right for winter fuel even if you are adding cetane booster. It's probably -30 fuel, so it drops the mileage a fair bit. You might try a winter front to reduce the cooling a bit from the cold weather. I would say you don't have huge problemos, but might want to check FICM voltages.

 

Thanks for the responses!

I will try to explain my self better on the numbers

12.4mpg avg is with the Excursion warmed up already and then driving on the hiway for 5 hours [drove 500km or 300miles] with outside weather being -10C
[I reset the EDGE CTS monitor while I started driving on the hiway and the overhead also]
Reads 12.4mpg avg CTS monitor 70miles/hr cruise set
Reads 15.4mpg avg ford Overhead 70miles/hr cruise set

On the dash trip I reset the trip guage when I filled the fuel tank prior to driving on the hiway for the 5 hours to get these numbers.

Hand calculated 13.2mpg [300miles drove/ gallons used 22.109]

This is with no tune stock other than the mods I said earlier.

I have owned this excursion for roughly 2 years [this excursion has always been a pig on fuel, just getting tired of watching my fuel guage going down quickly and costing $200.00 per a fuel fill up.

I owned a stock 2000 7.3l limited 4x4 Excursion limited prior to this 2003 6.0l Excursion and city driving would be 12.5mpg at least city and 18-20mpg hiway [1100km or 660miles per tank] and this 2003 6.0l has never even got close to those numbers even with Matts Tune.

Shell rotella 15/40 every 6000-8000km and fuel filters air filter when needed.

Flash version is the lastest[the crap one, thats why I got Matts tune Srl and even tried Looney's fuel saver nearly same results as above]

I guess I just have a dud![ mileage is only going to get worse with age but still have very low km 122,000km, so I hope I can either fix some things or maybe time sell ]

 

FICM voltage is 48.5

 

Ive noticed you cant trust the one in the truck, I just got back from filling mine up and the one in the truck showed 13.3 MPG and hand calculated it was 14.78

 

I think it depends how consistent your driving is. Mine usually says 14.0 mpg and hand calculated I get 13.5, so that's accurate enough for me

 

The way your Calculating is giving you a Tank Average But should be Close in your case since the Distence you drove

Tank Average will Almost Always be Less than actual MPG unless you drive Straight threw the Whole Tank with Little Idel time

And an Answer to your Question is Yes Low ECT Can/Will affect MPG

Winter Fuel Sucks and theres the Majoirity of the Loss

Next Oil Change go with a 5w40 Synthetic oil Anything to Help

I Over Inflate the 2 Front Tires By 10psi with my BFG 35in AT Tires Lots of Weight on the front