last post for mpg ongoing problem
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Freshman User
Joined: Feb 2003
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last post for mpg ongoing problem
OK after a couple of weeks of testing, and replacing act, ect and o2 sensors I still only get 5 mpg. The engine runs great, no black smoke, good acceleration, and have check all sensors.
I have checked for leaks, at this rate should be leaking fuel at about .5 gal /10 min, but i see know problem. rail pressure is where it should be. timing is good. brakes are not dragging.
alignment may be off a lttle.
Last call for any suggestions.
this is a 1988 f350 460 with 3.50 gears 4wd 16" tires.
I have read many times that 12mpg is about what this set up should get.
But I have spent enough time trying to figure this one out, I like the truck but maybe its time for a diesel.....
Looking for any input, Thanks
I have checked for leaks, at this rate should be leaking fuel at about .5 gal /10 min, but i see know problem. rail pressure is where it should be. timing is good. brakes are not dragging.
alignment may be off a lttle.
Last call for any suggestions.
this is a 1988 f350 460 with 3.50 gears 4wd 16" tires.
I have read many times that 12mpg is about what this set up should get.
But I have spent enough time trying to figure this one out, I like the truck but maybe its time for a diesel.....
Looking for any input, Thanks
Elder User
Joined: Jan 2000
Posts: 966
Likes: 2
From: Crooked River Ranch, OR
last post for mpg ongoing problem
One possible solution is to have your injectors checked on their spray pattern. If one injector is partially plugged and running lean the o2 sensor will pick that up and the computer will compensate by running the other 7 injectors rich. Also what T-stat are you running? It is possible if your running a 160 degree T-stat that the computer will continue to run the engine in the choke mode which adds time to the fuel injection pulse. From what I read in Charles Probst book on Ford fuel injection (page 160, 2nd paragraph under "Fuel Control") the ECT sensor considers a warm engine to be at 170 degrees or warmer.
Under diagnosis and trouble shooting for poor fuel economy that same book lists these top 5 items to look for in decending order of probable causes:
1. Fuel pressure regulator. Fuel return line blocked.
2. Air cleaner duct and Element
3. Scope engine for : Spark plugs, wires, coil, secondary wires, distributor cap, timing.
4. Run a "Quick Test" . To lengthy for me to copy here but something similar to checking for stored engine codes. Maybe someone else will want to elaborate...
5. Thermostat
Good luck, Deen
Under diagnosis and trouble shooting for poor fuel economy that same book lists these top 5 items to look for in decending order of probable causes:
1. Fuel pressure regulator. Fuel return line blocked.
2. Air cleaner duct and Element
3. Scope engine for : Spark plugs, wires, coil, secondary wires, distributor cap, timing.
4. Run a "Quick Test" . To lengthy for me to copy here but something similar to checking for stored engine codes. Maybe someone else will want to elaborate...
5. Thermostat
Good luck, Deen
Thread Starter
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Freshman User
Joined: Feb 2003
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last post for mpg ongoing problem
Ya i messed up:
I have that book, wish it when into the computer program more so i could do some mods. I have
check everything you suggested, i am thinking maybe the act signal is not making to the computer.
I have asked what the ontime of the injectors are so i can see if this is the problem but no one
knows. greg
I have that book, wish it when into the computer program more so i could do some mods. I have
check everything you suggested, i am thinking maybe the act signal is not making to the computer.
I have asked what the ontime of the injectors are so i can see if this is the problem but no one
knows. greg
Moderator
Joined: Dec 2001
Posts: 22,436
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From: Louisville,Ky.
last post for mpg ongoing problem
Are the <a href="http://service.bfast.com/bfast/click?bfmid=37919709&siteid=39251846">tires </a>the stock height? A taller tire will make your speedo slow and will show less miles traveled than you have actually gone, thus showing worse mileage than you are actually getting.
Just a suggestion, Jimmy
Just a suggestion, Jimmy
