Go Back   Ford Truck Enthusiasts Forums > Performance, Engines & Troubleshooting > Ford Inline Six, 200, 250, 4.9L / 300
Sign in using an external account
Register Forgot Password?


Welcome to Ford-Trucks Forums!
Welcome to Ford-Trucks.com.

You are currently viewing our forums as a guest, which gives you limited access to view most discussions and access our other features. By joining our community you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is fast, simple and absolutely free so please, join the Ford-Trucks Forums community today!





 
Reply
 
 
 
 
LinkBack Thread Tools Search this Thread
  #1  
Old 09-21-2009, 01:59 PM
1986F150six 1986F150six is offline
Postmaster
 
Join Date: Jul 2009
Location: Sheffield, AL
Posts: 2,622
1986F150six has a great reputation on FTE.1986F150six has a great reputation on FTE.1986F150six has a great reputation on FTE.1986F150six has a great reputation on FTE.1986F150six has a great reputation on FTE.
Gas mileage results for 4.9L in F150

From time to time, someone asks what mileage should be expected? Here are some records I have kept as I work on my personal truck. The truck is a 1986 F-150 short wheel base with 4.9L engine and 4 speed overdrive transmission. The rear end has a limited slip with 3.08 gears. The tires are Michelin X Radial [automobile] and are the original 215/75 X 15 size pressured to 35 PSI in front and 32 PSI in rear. It has 132,000 miles and still has the original catalytic converters (2) and muffler.

I purchased it in March of 2008 from the older gentleman who is the original owner. It was still almost original and needed TLC. It still had the original plug wires as well as hoses, etc. It ran horribly and belched black smoke and bucked violently upon deceleration. Vacuum hoses were missing and the feed back carburetor was not functioning properly. Well, that was my starting point...sorry it took so long.

All of the figures that will be provided are with me as the driver, driving the same route to work with similar weekend driving experiences. I live in a rural area, but have many stop signs while in town. None of these figures reflect highway only driving [those have been excluded].

Initial MPG = 10.41 [2 tanks]

Replaced carb with non-feed back model, removed EGR and air pump, and replaced all normal tuneup components and mileage increased to 15.64 mpg, but with frequent pinging. Thanks to FTE, I learned about Duraspark 2 ignition.

Duraspark 2 ignition installed with timing set at 10 degrees BTDC. It felt sluggish and mileage dropped to 14.10.

Adjusted timing and carburetor using a vacuum gauge [thanks again FTE]. At idle, the vacuum was 21 inches Hg. The truck ran better, but began to ping. After adjusting the vacuum to 19.5, the pinging ceased, performance was better and mileage averaged 15.67.

Even though the air filter was not filthy, I installed a Purelator and the next few tanks averaged 16.08.

In March of this year, a MSD box became available. It was installed without adjusting the plug gap [will be done soon] and the timing was set at 14 degrees BTDC. The mileage averaged 17.26 [13 tanks].

In June, I repaired the A/C [it gets hot in Alabama]. After 11 tanks, the average is 16.85 mpg.

Last week, I changed the transmission grease to synthetic and will monitor what effect, if any, this has. The effort to change gears has been sinificantly decreased.

I hope this information is helpful to someone. I have learned a great deal from reading[listening] to you more experienced members. Thanks!
Reply With Quote
  #2  
Old 09-21-2009, 02:52 PM
Econoline 150's Avatar
Econoline 150 Econoline 150 is offline
Elder User
 
Join Date: Oct 2007
Posts: 561
Econoline 150 is starting off with a positive reputation.
My 300 six & auto in my van usually does 18-20 on the highway depending if I have the a/c on (Kentucky gets purtee bad too !)
But, I have a fuel economy gauge to help and I drive like what I am (an old fart)
__________________
Bill Lloyd

1981 Ford F250 4 x 4 351M 4 speed
1993 Aerostar 3.0 V6 5 speed
Reply With Quote
  #3  
Old 09-21-2009, 08:52 PM
Jim_in_Omaha Jim_in_Omaha is offline
Freshman User
 
Join Date: Sep 2005
Location: E. of Omaha in Iowa hills
Posts: 47
Jim_in_Omaha is starting off with a positive reputation.
I got 12.4 today '96 4wd. Probably half that was pulling an empty 6X10 dump trailer. Pulled a 12 foot enclosed 250 miles and got about 11. I have not measured it since we got the dump trailer loaded. Been hauling gravel through the hills. Probably not far off from the 12 because I drive it very carefully and slow.

I do know this much. If you let it sit around doing much idling it will really drop the mileage. Seems like mine uses about as much gas sitting at idle as it does moving.
Reply With Quote
  #4  
Old 09-23-2009, 08:35 PM
abcdefg1675 abcdefg1675 is offline
New User
 
Join Date: Aug 2008
Posts: 2
abcdefg1675 is starting off with a positive reputation.
I figured I should add in my truck, although its an F250.

1987 F250 'custom' (no options, not even a tape deck).
326,000 miles
4.9L EFI L6
4.10:1 10.25" axle
2WD
265R75 tires, bald from having 1.5" of toe-out

runs rough at idle, backfires constantly when deaccelerating, exhaust reeks of gas fumes worse than a lawnmower. It's slow, it sounds like a tractor, it pauses and takes 2+ seconds to process when you stomp on the gas pedal....Its well aged.

Unloaded:
Spending 2 hours in stop-and-go traffic brings me to about 11-12mpg. Highway driving, non-stop, for 7 hours @55mph up and down some mild mountain passes averages 14.5-15.5mpg, turning about 2600rpm.

Loaded: I've no idea, $30 worth of gas to do dump-runs all day long, I didnt really care.
Reply With Quote
  #5  
Old 09-25-2009, 11:51 PM
|WYG|SS's Avatar
|WYG|SS |WYG|SS is offline
Senior User
 
Join Date: Sep 2009
Posts: 379
|WYG|SS is starting off with a positive reputation.
with my 93 f150 4.9l 5spd 4x4 126,000. ive averaged 11-14mpg in winter with hubs locked in. summer i averaged 15-16mpg and ive seafoamed it twice and went up north in wisconsin to the pipeline with my spare in the bed and back of my cab filled to the top with camping gear and bed full of wood and i averaged 19mpg on the hwy, this really impressed me. now i got 5.0l injectors installed (20#) and im going to try and see what i get now.
Reply With Quote
  #6  
Old 09-28-2009, 02:17 AM
Iversen-fords's Avatar
Iversen-fords Iversen-fords is offline
Senior User
 
Join Date: Sep 2007
Location: H20town South Dakota
Posts: 491
Iversen-fords is starting off with a positive reputation.
last time i checked, i got 16.6 driving 65-75 for 260 miles with my 700+ lbs tool box in the box. Stock everything on it but the smog pump delete and straight pipe after the cat. the 3.08s and 5 speed help. the mpgs used to be better but its just a ranch pickup so it doesnt matter what i get now
__________________
Frankie aka Oneye
66 Mustang coupe 289
97 F250 HD 460 5speed
80 VW rabbit pickup diesel. 1.5 Custom Turbo-- RIP
95 Chevy Berretta 2.2 5speed
Reply With Quote
  #7  
Old 09-28-2009, 05:17 AM
Greyf100's Avatar
Greyf100 Greyf100 is offline
Elder User
 
Join Date: Apr 2009
Posts: 725
Greyf100 is gaining momentum as a positive member of FTE.
'81 F100
300/c6
2.75 rear
225/70R15
4700# GVWR

egr block off, smog removed, straight mechanical advance

around town i avg 14MPG, on the highway 17MPG @ 70MPH / 19MPG @ 60MPH
Reply With Quote
  #8  
Old 09-28-2009, 08:27 AM
6CylBill's Avatar
6CylBill 6CylBill is offline
Post Fiend
 
Join Date: Jan 2007
Location: Almost Heaven
Posts: 7,021
6CylBill has a great reputation on FTE.6CylBill has a great reputation on FTE.6CylBill has a great reputation on FTE.6CylBill has a great reputation on FTE.6CylBill has a great reputation on FTE.
I have the E40D automatic with a 4.11 gear and 31'' tires all the way around. I get about 16 mpg cruising at 60 mph. I get more than 18 if I follow real close to a wind breaker (like a U-Haul truck or something like that). I don't recomend this, I just found this to be interesting. Shows just how much wind resistance hurt mileage.
__________________
Rise and rise again..

until Lambs become Lions
Add me on FaceBook! https://www.facebook.com/bill.holsinger.5?ref=tn_tnmn
Reply With Quote
  #9  
Old 09-29-2009, 07:15 PM
guyina4x4 guyina4x4 is offline
Junior User
 
Join Date: Jul 2004
Posts: 57
guyina4x4 is starting off with a positive reputation.
81

I had a 81 F150 extended cab and long bed 4x4, 300 6, bone stock, stripped down, no a/c, 4 speed trans with granny low.

at 55 on the highway I got 21mpg regularly
at 60 to 65 I got 16 at best

I loved that truck

I just got a 95 reg cab 4x4, I hope it does al least 15 or 16
Reply With Quote
  #10  
Old 09-30-2009, 08:07 AM
Novakane Novakane is offline
New User
 
Join Date: Aug 2009
Posts: 12
Novakane is starting off with a positive reputation.
I have a 94 f150 4.9 automatic extended cab that I've been tuning the ecm here for a couple of weeks. Well I live out in the country so I don't do much interstate driving. I mostly do city driving with a high speed of 55. I did an average the other day of 18.9 city mileage....I might add that I pulled an empty trailer for about 50miles, and I also pulled a loaded trailer (6500lbs.) for 18 miles. I am very pleased with the results so far....Once I get a full tank put on the truck without pulling anything I will let you guys know, but so far so good....My clunker is a keeper now!
Reply With Quote
  #11  
Old 09-30-2009, 07:13 PM
greyghost85's Avatar
greyghost85 greyghost85 is offline
Postmaster
 
Join Date: Jun 2007
Location: St Louis
Posts: 3,694
greyghost85 has a good reputation on FTE.greyghost85 has a good reputation on FTE.
i get zero,goose egg, nada! cause she's sittin in the yard, waitin for a motor!
Reply With Quote
  #12  
Old 10-10-2009, 08:49 PM
allis327's Avatar
allis327 allis327 is offline
Senior User
 
Join Date: Oct 2005
Location: Melrose MN
Posts: 377
allis327 is starting off with a positive reputation.
I have 91 efi how do I delete the smog pump, what size belt, will this effect the motor in agood or bad way The pipe to the exaust is welded shut so the pump is not really doing anything.
__________________
2002 f350 superduty crewcab long box 4x4

6637 w/ pete's cover, 4" turbo back exhaust, zoodad, dipricol optix guages, warn premium lockouts, ccv mod, foil delete, Tru-cool tranny cooler
91f150 4x4 I6
Reply With Quote
  #13  
Old 10-11-2009, 12:56 PM
Harte3 Harte3 is offline
Postmaster
 
Join Date: Dec 2006
Location: Spokane, WA
Posts: 3,237
Harte3 is gaining momentum as a positive member of FTE.Harte3 is gaining momentum as a positive member of FTE.
With EFI best not delete anything. Rather, make sure everything is working properly including the smog pump.
__________________
1983 F150 300 I6, Comp Cam 260h and lifter kit, Port/Polished head, Offy DP Manifold, Holley 4160/1848-1 465 cfm, EFI Exhaust manifolds, Walker Y Pipe to 3-Way Cat, generic Turbo Muffler, Recurved DSII, Mallory HyFire 6a & ACCEL Super Stock Coil, Taylor Spiro Pro Wires, EFI plugs.
"It'll put out what ever it puts out." fordman75
Reply With Quote
  #14  
Old 10-12-2009, 10:28 PM
IowanStraight6's Avatar
IowanStraight6 IowanStraight6 is offline
Elder User
 
Join Date: Dec 2008
Location: 50450 iowa
Posts: 795
IowanStraight6 is starting off with a positive reputation.
Get this mine when it ran got 18-20 best with highway, town, gravels
1994 4.9 (Fun1) programed
OBDI
3.55
E40D
LB, RC, 2wd

Dad gets 15-16 best with highway, town and gravel driving
1996 OBDII
3.08
E40D
LB, RC, 2wd

Anyone figure out why this would be?
__________________
Nick
94 f150 2wd,
E40D 300I6, reg cab 8' bed, Tow Pac. project
You rarely use 1st unless you start on a hill with some a-hole trying to check your prostate with his prius. Unlike ricers we can't get parts at Walmart ...
Then Ford blew it totally with the 10th gen and it never got better since.
96 f150 4wd, 4R70W 302V8, super cab 8' bed, Tow Pac. daily driver
Reply With Quote
  #15  
Old 10-13-2009, 09:17 AM
6CylBill's Avatar
6CylBill 6CylBill is offline
Post Fiend
 
Join Date: Jan 2007
Location: Almost Heaven
Posts: 7,021
6CylBill has a great reputation on FTE.6CylBill has a great reputation on FTE.6CylBill has a great reputation on FTE.6CylBill has a great reputation on FTE.6CylBill has a great reputation on FTE.
Your dad has a heavier foot!
__________________
Rise and rise again..

until Lambs become Lions
Add me on FaceBook! https://www.facebook.com/bill.holsinger.5?ref=tn_tnmn
Reply With Quote
Old 10-13-2009, 09:17 AM
 
 
 
Reply

Go Back   Ford Truck Enthusiasts Forums > Performance, Engines & Troubleshooting > Ford Inline Six, 200, 250, 4.9L / 300

Tags
12, 1986, 49, 49l, 96, e250, f150, ford, inline, michelin, mpg, psi, radials, slow, spec, specs, timing

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not 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 On
Trackbacks are On
Pingbacks are On
Refbacks are On

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Gas Mileage Recipe - 4.9L/300 1986F150six 1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks 54 10-21-2014 10:48 AM
Carter YF vacuum ports [vacuum timing adjustment] 1986F150six Ford Inline Six, 200, 250, 4.9L / 300 10 02-25-2013 01:21 PM
MPG observations [w/o vacuum advance] 1986F150six Ford Inline Six, 200, 250, 4.9L / 300 9 08-10-2011 05:21 PM
351M ignition/timing/carb trouble flashover604 335 Series- 5.8/351M, 6.6/400, 351 Cleveland 2 02-09-2010 04:39 AM
92 Explorer XLT 4x4 Sudden Drop In Gas Mileage blues1947 2.6, 2.8, 2.9, 4.0 & SOHC 4.0 V6 3 02-07-2005 08:33 AM



All times are GMT -5. The time now is 11:08 PM.


Powered by vBulletin® Version 3.8.7 AC1
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Advertising - Terms of Use - Privacy Statement - Jobs
This forum is owned and operated by Internet Brands, Inc., a Delaware corporation. It is not authorized or endorsed by the Ford Motor Company and is not affiliated with the Ford Motor Company or its related companies in any way. Fordģ is a registered trademark of the Ford Motor Company.

vbulletin Admin Backup