Lower than Expected MPG, problems? - PowerStrokeNation : Ford Powerstroke Diesel Forum
Reply
 
LinkBack Thread Tools Display Modes
post #1 of 11 (permalink) Old 08-21-2008, 07:51 PM Thread Starter
PSN Local
 
Join Date: Nov 2007
Location: College Station Texas
Posts: 140
Lower than Expected MPG, problems?

I have been checking my fuel mileage and lately it has dropped lower than I have ever seen it. I am getting about 13 mpg driving around town and only high 17's on the highway. I know the ULSD has probably affected these numbers but I wouldn't expect them to be that low. I was able to get 19-20 last summer on the highway. I have also started to add some 2 stroke oil with the fuel (about 1 oz. per gallon) and that has made no change on the mileage, but did quiet the motor down. I keep regular oil changes and have a very mild driving style, so does anyone have any ideas on why the mileage is on a steady decrease? Any input is welcome. Thanks.

2003 7.3 XLT FX4, AFE Stage 2, Regulated Return, Bowl Delete, 3/8" line from tank to heads, Pre/Post Filters, Tank mods, DP F5: 60T, 80E, 120R, 6.0 IC, 6.0 Trans Cooler, Suncoast Shift Kit, Wicked Wheel, ITP Boost Annihilator, Di Procol Optix, Straight Pipe, CCV, 285/75/16 BFG AT's
breyrw is offline  
Sponsored Links
Advertisement
 
post #2 of 11 (permalink) Old 08-22-2008, 04:10 PM
PSN Veteran
 
DZL JIM's Avatar
 
Join Date: Sep 2007
Location: Northeast Ohio
Posts: 2,080
Re: Lower than Expected MPG, problems?

How many miles on the motor?
Adequate air in your tires?
Blocked air filter?
Blocked fuel filter?
How much 2 stroke oil are you adding?
These are the simplest things to think about. If these are all good, worst case could be blocked injector nozzles and/or worn Plunger & Barrels. The latter is very rare in the Super Duty's due to Tungsten coated parts, but it could happen. I'd guess blocked nozzles before damaged P&B's.
DZL JIM is offline  
post #3 of 11 (permalink) Old 08-22-2008, 04:46 PM
JDG's #1 Fan
 
99F250Smitty's Avatar
 
Join Date: Dec 2007
Location: West Milton, OH
Posts: 3,470
Send a message via AIM to 99F250Smitty
Re: Lower than Expected MPG, problems?

I don't do much better. I get high 13's, low 14's around town, and would be happy with 17's on the highway. Last highway trip I took, i got 16.4 mpg, with a tonneau cover on, and running 1 oz. per gallon 2 stroke.

Brian
_____________________________________________
99.5 F250 Extended Cab Short box. 4x4.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.



To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.



To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
99F250Smitty is offline  
 
post #4 of 11 (permalink) Old 08-22-2008, 11:29 PM Thread Starter
PSN Local
 
Join Date: Nov 2007
Location: College Station Texas
Posts: 140
Re: Lower than Expected MPG, problems?

Quote:
Originally Posted by DZL JIM View Post
How many miles on the motor?
Adequate air in your tires?
Blocked air filter?
Blocked fuel filter?
How much 2 stroke oil are you adding?
These are the simplest things to think about. If these are all good, worst case could be blocked injector nozzles and/or worn Plunger & Barrels. The latter is very rare in the Super Duty's due to Tungsten coated parts, but it could happen. I'd guess blocked nozzles before damaged P&B's.
There are about 118k on the motor, tires have around 65 psi in them, the big afe filter has some dirt on it, but not covered, I did put on a 2 micron post pump filter with the NAPA filter head that is fairly common and I wonder if that could be restricting flow. I run about 60 psi on the regulator and right now I have now way to check the pressure at the pump outlet to see how much head loss I have between the pump and regulator. It just puzzles me how I could better mileage with a stock truck than I do now with an econo tune.

2003 7.3 XLT FX4, AFE Stage 2, Regulated Return, Bowl Delete, 3/8" line from tank to heads, Pre/Post Filters, Tank mods, DP F5: 60T, 80E, 120R, 6.0 IC, 6.0 Trans Cooler, Suncoast Shift Kit, Wicked Wheel, ITP Boost Annihilator, Di Procol Optix, Straight Pipe, CCV, 285/75/16 BFG AT's
breyrw is offline  
post #5 of 11 (permalink) Old 08-22-2008, 11:41 PM
PSN Veteran
 
DZL JIM's Avatar
 
Join Date: Sep 2007
Location: Northeast Ohio
Posts: 2,080
Re: Lower than Expected MPG, problems?

Quote:
Originally Posted by breyrw View Post
It just puzzles me how I could better mileage with a stock truck than I do now with an econo tune.
Pull the chip and run it, see what you get. If mpg is still poor, you know it's not the programming.
My 'Economy' program is more hp than the others and I get better mpg on stock or light tow...
DZL JIM is offline  
post #6 of 11 (permalink) Old 08-25-2008, 03:38 PM Thread Starter
PSN Local
 
Join Date: Nov 2007
Location: College Station Texas
Posts: 140
Re: Lower than Expected MPG, problems?

Another thing that has been in my mind is trip length. A lot of my trips are short length. The motor usually is just reaching full operating temps by the time I get to where I am going. How much will engine temps affect mileage. This does not address the issue of highway mileage falling though.

2003 7.3 XLT FX4, AFE Stage 2, Regulated Return, Bowl Delete, 3/8" line from tank to heads, Pre/Post Filters, Tank mods, DP F5: 60T, 80E, 120R, 6.0 IC, 6.0 Trans Cooler, Suncoast Shift Kit, Wicked Wheel, ITP Boost Annihilator, Di Procol Optix, Straight Pipe, CCV, 285/75/16 BFG AT's
breyrw is offline  
post #7 of 11 (permalink) Old 08-25-2008, 09:03 PM
PSN Veteran
 
DZL JIM's Avatar
 
Join Date: Sep 2007
Location: Northeast Ohio
Posts: 2,080
Re: Lower than Expected MPG, problems?

Quote:
How much will engine temps affect mileage?
I'd say quite a bit.
I do a lot of local, in town driving and burn WVO, so poor cetane (or whatever) from the WVO combined with low temps and my mileage sucks.
But head to the hgihway and it's much better. Been averaging to 18.3 or so combined driving...
DZL JIM is offline  
post #8 of 11 (permalink) Old 08-30-2008, 01:48 AM
blame the dog..
 
JLDickmon's Avatar
 
Join Date: Jun 2008
Location: SW Lower Michigan
Posts: 1,945
Re: Lower than Expected MPG, problems?

Quote:
Originally Posted by breyrw View Post
There are about 118k on the motor, tires have around 65 psi in them, the big afe filter has some dirt on it, but not covered, I did put on a 2 micron post pump filter with the NAPA filter head that is fairly common and I wonder if that could be restricting flow. I run about 60 psi on the regulator and right now I have now way to check the pressure at the pump outlet to see how much head loss I have between the pump and regulator. It just puzzles me how I could better mileage with a stock truck than I do now with an econo tune.
my econo tune did wonders..
do you have a smoke stain on the side of the bed behind the exhaust?

Quote:
This site needs new newbs.
JLDickmon is offline  
post #9 of 11 (permalink) Old 08-30-2008, 03:25 AM
MPG Moderator
 
Dave Whitmer's Avatar
 
Join Date: Jul 2007
Posts: 1,083
Re: Lower than Expected MPG, problems?

Have you tried the really dumb, but cheap thing? Rebooting you ECM by disconnecting the batteries?

2000 F-350 SC 4x2 6 speed
3.08 gears Gear Vendor Overdrive
Slammed 4"
Rugged Air Dam
315,000 miles
Dave Whitmer is offline  
post #10 of 11 (permalink) Old 09-01-2008, 08:31 PM Thread Starter
PSN Local
 
Join Date: Nov 2007
Location: College Station Texas
Posts: 140
Re: Lower than Expected MPG, problems?

There is no smoke stain on the truck, just a very small bit of soot on the end of the tailpipe. I have not had the battery cables off since about April, but I can try that. This weekend I made trip that was about 215 miles, (about 90% highway) all of the miles were on the stock setting. The mpg was 16.5 and the same trip on the 80E tune gets me about 17.8 mpg. The thing that bugs me is that I used to get around 19+. The last part that I have put on the truck was a regulated return, so I am thinking that maybe that is causing something, I just don't know what exactly.

2003 7.3 XLT FX4, AFE Stage 2, Regulated Return, Bowl Delete, 3/8" line from tank to heads, Pre/Post Filters, Tank mods, DP F5: 60T, 80E, 120R, 6.0 IC, 6.0 Trans Cooler, Suncoast Shift Kit, Wicked Wheel, ITP Boost Annihilator, Di Procol Optix, Straight Pipe, CCV, 285/75/16 BFG AT's
breyrw is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the PowerStrokeNation : Ford Powerstroke Diesel Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome