EX programmer issues...

[GiJoe2go]

O.k., being new to diesels, I have encountered a problem that has me stumped... I have an '03 Excursion 7.3L, and I have purchased a programmer for it. My Problem is this: When I was test driving the rig before I bought it, I noticed the onboard computer said it was getting 15.9 MPG on the overhead screen. We had the truck for 2 days, and it maintained that number. We bought the truck a week later, and saw that it had dropped down to 12.5 MPG. We found out it had a programmer, but one of the lot guys had reset the computer and stole the programmer.

Since then, I purchased a new Superchips Vortex and programmed it for performance, made sure we weren't taking the engine past 2000 RPM, and drove it for 3 weeks. Mileage didn't change one bit, and we even did the math ourselves, not totally trusting the computer. So I reprogrammed the computer back to stock, returned the Superchips programmer, and purchased a Hypertech programmer. Have had it installed for 2 months now, and STILL, nothing has changed. MPG still remains at 12.5...

Everything on the engine is stock, but I have upgraded the air filter to a K&N filter for the stock air box...

I'm sort of lost as to what to check next... Anyone have any ideas?? I don't have anyone here to ask, so I'm turning to the "EXPERTS" for some straight up advice...

[AggieExcursion2010]

the lil monitor on the roof isnt worth your time....good ole long division is the way to roll. that seems rather low. If i floor it in my 7.3 Ex on 37's i get like 12mpg city. You might want to reset the monitor by holding both buttons for a sec and letting go....something might be messed up in there that just has it only displaying 12.5 - i say do find a downhill slope, go 30mph up it then just cruise down it and reset ur monitor at the top....if that thing never reads 35+mpg on the way down the hill...i'd say its very...very busted. You SHOULD be seeing a whole lot better fuel econ then that.

IM NO EXPERT - but i do know that either your comp is screwed up or your getting robbed on fuel from something else
how is it geared?

[mschn99]

any time you play with the computers on these you throw the overhead computers off. Un-programed they are usually within a couple tenths of a mile per gallon...and are probably more accurate than hand calculations cause nobody....no matter how good...can ever get exactly the same amount of fuel in every time....

BUT when you program the truck...you change all kinds of parameters and mess up what its gonna read....basically you make that funcion useless...

[GiJoe2go]

Actually, in between programers, when things were back to stock settings, it continued to read 12.5... I notice an increase in power with the Hypertech installed, but nothing else is different...

And does the computer display overhead fluxuate when you put the throttle to the floor?? Does it display plus or minus mileage with the fluxuation on the throttle??? I've never sen it do this...

And everything on the truck is stock, other that the 35 in. tires and 6" lift kit...

[01excursion7.3]

First, get rid of the K&N, go to a dry method. I personally have (I think aem) Same cone style element, but dry filter. I've heard good things about the ford AIS intake, I would have got that, but got mine instead because I didn't know anything at that time (The ORG has helped make me smarter). All I have for performance is the intake, and 4" exhaust, on stock tire sizes, and I'm getting 17mpg in the winter on the winter blend. I got around 19 on the highway in the summer.

Mods to come for better mileage for me is a chip, either Tony Wildman (See Raul at stealth) or the DP tuner, (see dp-tuner.com) I don't know the gentleman and Lady at that company's name, or I would post them. And I'm gettin gauges, Amsoil fluids all around, and a couple other things that aren't mileage based.

But you should be seeing better than that anyways. Change fuel filter, fresh oil change, and be easy on the fuel. U might have other issues, but thats a start, and the guys on here would have more suggestions.

But heres a for ya to get to the top anyways.

[01excursion7.3]

Whoops, just saw you have 35" tires, that would have an effect, but I wouldn't think that much of one.

[AggieExcursion2010]

it shouldnt be that bad. i can make 20-21mpg highway on 37's. i think ur mpg calculator is most likely on the fritz. but like i said...im no expert.
that computer will update narly every second after you reset it by holding mode and (button next to it) for 2 or 3 seconds. if you FLOOR it you can see 4's and 5's...if you idle going 45+donhill u can see 60/70mpg. it updates alot and if it hasnt been reset in several tanks...your looking at a very VERY accurate avg from many MANY numbers