2005 Mileage dropping, need to make some improvements

[BSDeality]

I keep track of every fillup for my truck and this YTD the mileage is constantly going down. I'm at the point where I'm only driving the truck 1.5 days a week when I have to tow, the rest of the week I let it sit unless I'm hauling big stuff.

I track my fuelups in Excel for my business and the data matches up. AVG economy towing a little 6x12 trailer with about 3K lbs total has been 11.3mpg around town. Last summer I was averaging 13.3mpg same driving weight.

Average $ per mile in 2005 was $.21
Average $ per mile in 2006 is $.26 so far

Last fill up was 9.96mpg and $.31 per mile! It's time I look at improving my mpg.

What would some possible causes for the mileage drop be? Are there any cheap/easy checks? I've got 25K miles on it, 23K of those were in about 9 months, the last 2k i've been weening it on since march (bought another truck). Did the first oil change @ 3K, then pushed them to 5K, however I'm going back to 3K increments. I changed the fuel filter when this started dropping in april, but noticed zero difference. The truck is stock components so far too, no dealer flashes have done either.

HELP! [img]/ubbthreads/images/graemlins/shrug.gif[/img]

[Gibsonian]

How bout your air filter?

[BSDeality]

I checked it at the last oil change and it appeared to be pretty clean still. Perhaps looks are decieving, Does K&N make a drop in replacement?

[BSDeality]

Also, just remembered... When I start the truck for the first time in the day the there is a burp/scuff/grind noise that sounds like its coming from the turbo. It only does it first thing in the morning then its done for the day. thoughts?

[OMCUSNR]

Not enough data to go on. It would be very helpful if you would add the truck & all modifications to your signature.

All I know is you have a 2005 F-series PSD w/ a 6.0, so
F-?
trans?
rear?
body?
tires?
HOW DO YOU DRIVE IT? WHERE DO YOU DRIVE IT?

To maximize fuel economy, 2k rpms over long distances w/ properly aired tires.

There are lots of culprits in loosing millage, but we need more info to help pin it down.

[BSDeality]

[ QUOTE ]
Not enough data to go on. It would be very helpful if you would add the truck & all modifications to your signature.

All I know is you have a 2005 F-series PSD w/ a 6.0, so
F-?
trans?
rear?
body?
tires?
HOW DO YOU DRIVE IT? WHERE DO YOU DRIVE IT?

To maximize fuel economy, 2k rpms over long distances w/ properly aired tires.

There are lots of culprits in loosing millage, but we need more info to help pin it down.

[/ QUOTE ]
F350
5spd auto
3.73 rear/4x4
supercab/longbed
stock 18"/continental (POS's)

I was a little low on the PSI in my tires, just topped them off on sunday actually. they were 50/50psi in the front. 46/47 in the rear. I aired them up to 65 in the front and 70 in the rear.

As for driving style. I run cruise control on the highway, keeping it under 70 if possible. I tow during the week, try to keep it under 2500rpm when accelerating and coast as much as possible.

[OMCUSNR]

OK - With that info, I'd say you "should" be getting about 17 on the highway unloaded @ 70, about 15 in town w/ heavy stop-go, and about 13 towing 8-9k#s @ 62.

I'm not sure what the latest callibration is for an 05, but before I started hanging aftermarket stuff on it, I'd get it to a competent dealer to look at it. It may be the air filter (but the Donaldson holds alot stuff & still works well) - how long have you had it on? It might be the EGR going south on you. It might be a bad batch of fuel or fuel filters. If the filters test out ok, the dealer may be able to see what, if any codes its throwing. If its not throwing a code, the dealer most likely will say its within specs.

AS to mods for economy, I don't think anyone can pay them off in fuel savings. They really aren't designed to do economy. I'd not put a K&N on any truck I own, but some guys like em. The ONLY AM air box I'd consider is an AFE Progaurd stage II, but I couldn't get it to pay for itself in under 5yrs at the rate I drive (17k/yr).

My favorite suspect at this point would be the EGR.

[BSDeality]

I buy my diesel from one or two stations, both are very high volume so i'd guess its not fuel.

I've heard that the updates bring down mpg even more, lower boost, if i'm into single digits for MPG I'll be in real trouble. I should replace the air filter next I guess. The question becomes should I drop in a replacement or put in an intake? Then add an exhaust? I've had my eye on a MBRP dual turbo back.

[05F250PS]

[ QUOTE ]
OK - With that info, I'd say you "should" be getting about 17 on the highway unloaded @ 70, about 15 in town w/ heavy stop-go, and about 13 towing 8-9k#s @ 62.

I'm not sure what the latest callibration is for an 05, but before I started hanging aftermarket stuff on it, I'd get it to a competent dealer to look at it. It may be the air filter (but the Donaldson holds alot stuff & still works well) - how long have you had it on? It might be the EGR going south on you. It might be a bad batch of fuel or fuel filters. If the filters test out ok, the dealer may be able to see what, if any codes its throwing. If its not throwing a code, the dealer most likely will say its within specs.

AS to mods for economy, I don't think anyone can pay them off in fuel savings. They really aren't designed to do economy. I'd not put a K&N on any truck I own, but some guys like em. The ONLY AM air box I'd consider is an AFE Progaurd stage II, but I couldn't get it to pay for itself in under 5yrs at the rate I drive (17k/yr).

My favorite suspect at this point would be the EGR.

[/ QUOTE ]

Could you elaborate how EGR would make that significant difference?

[wpetko]

You may not want to hear this, but the cruise control doesn't help your mileage. It can't see a freeway overpass or a hill so it doesn't anticipate it. When the trucks starts uphill the cruise control holds the speed by opening the throttle and adding fuel. Going downhill it will let off on the throttle to, once again, maintain speed. When things level off after the downhill run watch your tachometer, RPMs will spike up as fuel is once again added to establish the level cruising speed that was previously selected. The only way that cruise control will help mileage is if you are truly a crappy driver incapable of holding a steady economical speed. In that case, cruise control is better than nothing. Since, I'm sure that's not the case, try driving without the cruise. I doubt that this will eliminate your mileage troubles entirely, but every little bit helps. OH, by the way - I have cruise control on my truck and I'm not saying that it's useless. It really does relieve fatigue on long level stretches of highway where there aren't too many hills.
I agree completely with some of our friends that have already answered you. Aftermarket mods won't increase mileage enough to pay for themselves; at least not for many miles. The most important factor in mileage is driving technique followed by tire pressure. It sounds like you've corrected your tire pressure so you are halfway there. You mentioned that you don't use the truck much now - only when towing and hauling heavy loads. I'm the same way now. Remember, these trucks won't get the same mileage when towing as they do solo. I get 11 mpg - 13 mpg when towing the 5th wheel in my sig (no mountains where I live). Your mileage may be a little low, but get an accurate baseline mileage by running solo for at least a half a tank or so on a calm day on level road without a head wind if possible. If you don't like your solo baseline mileage then pursue some of the suggestions you read here or take it to the dealer for evaluation.
Good luck.

[OMCUSNR]

[ QUOTE ]
Could you elaborate how EGR would make that significant difference

[/ QUOTE ]

I'm figuring that a gummed up / carboned up EGR is messing with the PCM.

BSD,

It sounds to me like you want to use this as an excuse to modify your truck. Its your truck, & your money. After all I've read here & elsewhere, I can not see you recovering the cost of the add ons in fuel savings in under 5 yrs. The recal might just surprise you, and it might point to another area you are having a problem with & don't realize it yet. Are you making oil? Do you have a leaking injector?

If you are going to mod-
1st real gauges
2nd 4" exhaust
3rd tuner
4th AM air box.

The OEM Donaldson is the best price/performance/protection ballancing act available. If you really think you need a different box, you're going to sacrifice one or two of those to get the 3rd. A donadlson replacement is about $55, and should be good for 30k in normal usage. I, personally can't see the value in degrading the protection af a $3k turbo for a few extra MPG.

Good luck, & have fun!

[agdodge4x4]

I disagree. I keep a mileage log, and since my F250 2005 4x4, short bed, crew cab was new it has gone from 14mpg to 12.5-13mpg..thats city, HEAVY city driving every day. On the highway i can squeeze out about 15 doing 70-80 most of the time.

I dont see anything wrong with that kind of mileage. I currently have 17,000 miles, and as of this morning, i pulled 13.9, mostly highway. Its a heavy truck, with a V8, this aint a 6 cyl cummins so dont expect super mileage.

[Floridayfz450]

Take it in to the dealer. Mine gets 20 mpg unloaded on the highway at around 75 (2k RPM). I noticed a nice increase when I added the Edge juice and exhaust.

[BSDeality]

I'm going to wait it out for the time being, see what sort of mileage I get with the proper air pressure in the tires first. recheck. Next I'll change the air filter. recheck. then probably head to the dealer to have them check it out if it doesn't improve slightly.

My concern was the mileage seems to be going the opposite way its supposed to with break-in. I don't drive it harder now than I did when I first got it. 4mpg doesn't sound like a lot, but 9.96mpg to 13 is difference of 31%!

[06Clone]

[ QUOTE ]
Take it in to the dealer. Mine gets 20 mpg unloaded on the highway at around 75 (2k RPM). I noticed a nice increase when I added the Edge juice and exhaust.

[/ QUOTE ]

Yes, take it to the dealer, and refuse to pick it up until they either find the problem or replace it under lemon law. Don't expect to get 20 out of a 6.0 unless you are on the interstate at sea level breathing Florida air... My modified 7.3 will get 26 in FL @ 55mph but I don't drive there very often.
The SD HD filter is the best bang fo the buck. Low cost MPG mods are:
1. Run 85 psi in all 4 tires. Ignore anyone who says otherwise.
2. Remove the grill and cut out the FG header in front of the air box intake pipe. Replace grill. Cost = $0 + 1 hour
3. Replace 3in DP with header wrapped SS 4in DP. Delete cat. Replace with 4 to 5 to 3.5 expansion pipe sized similar to Cat. Cost $160+3hr
4. Use diesel fuel additives - I can't tell you which one is best.
No go ***** at the dealer. [img]/ubbthreads/images/graemlins/warmsmile.gif[/img]