1997 F-150 4x4 4.6 running rich
#1
03-24-2017, 09:14 PM
Join Date: Mar 2017
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1997 F-150 4x4 4.6 running rich
Hey guys so i am new to this website and am not quite sure how this all works.
I have done a lot to my truck through out the 2 years I've owned it. I have noticed i'm getting bad MPG around 10-11 in the city and on a good day 13-13.5 on the highway. I know being a 4x4 and V8 it isn't going to do great but it should be doing better than that. I have replaced all 4 O2 sensors, Intake gasket, Mass air flow sensor, Thermostat, air filter and a lot more. It is running on all 8 and has a new rebuilt transmission. I do have a leveling kit with 275 tires on it. Hooked up a scan tool with a friend mechanic and all the readings looked okay. O2 sensors took a little bit to heat up but all the banks were in specs. Yet the Air to Fuel ratio wasd at like 155 and i think it should be at like 152? not quite sure off the top of my head. This truck has always had routine maintenance just started running rich. Anyways, any help or advice would help a lot! thanks!
I have done a lot to my truck through out the 2 years I've owned it. I have noticed i'm getting bad MPG around 10-11 in the city and on a good day 13-13.5 on the highway. I know being a 4x4 and V8 it isn't going to do great but it should be doing better than that. I have replaced all 4 O2 sensors, Intake gasket, Mass air flow sensor, Thermostat, air filter and a lot more. It is running on all 8 and has a new rebuilt transmission. I do have a leveling kit with 275 tires on it. Hooked up a scan tool with a friend mechanic and all the readings looked okay. O2 sensors took a little bit to heat up but all the banks were in specs. Yet the Air to Fuel ratio wasd at like 155 and i think it should be at like 152? not quite sure off the top of my head. This truck has always had routine maintenance just started running rich. Anyways, any help or advice would help a lot! thanks!
#4
03-25-2017, 02:47 AM
Explain the numbers your using please.
All Scanner don't present the data the same way.
Normally the long term fuel times are the best clue to how well the fuel to air ratio is doing.
The Ox sensors set the base line by their calibration.
If everything were perfect the LTFTT would be zero shifted which means neither minus or plus side of their table center.
The short term trims will vary according the throttle and load.
The program monitors are not finding anything out of tolerance to set any code.
You may be trying to chase perfection which you cannot have in these machines especially on a 19 year old engine.
There are many variables for the program to deal with so the program is set up to self adjust within limits before any codes are set that require repairs.
If the program were set that tight you would be trying to fix something all the time.
The program can be set much tighter for all operational tolerances but that would be fool hardy for a manufacture to do to an owner plus his reputation..
Good luck.
All Scanner don't present the data the same way.
Normally the long term fuel times are the best clue to how well the fuel to air ratio is doing.
The Ox sensors set the base line by their calibration.
If everything were perfect the LTFTT would be zero shifted which means neither minus or plus side of their table center.
The short term trims will vary according the throttle and load.
The program monitors are not finding anything out of tolerance to set any code.
You may be trying to chase perfection which you cannot have in these machines especially on a 19 year old engine.
There are many variables for the program to deal with so the program is set up to self adjust within limits before any codes are set that require repairs.
If the program were set that tight you would be trying to fix something all the time.
The program can be set much tighter for all operational tolerances but that would be fool hardy for a manufacture to do to an owner plus his reputation..
Good luck.
Last edited by Bluegrass; 03-25-2017 at 02:54 AM.
