hi my f 150 5.4 V8 is running to lean on both banks according to my code reader i have replaced the fuel filter cleaned up the air filter and im about to put in seafoam in the gas tank to clean out the jets and carb if this dosent help what would you advise i check next i thought fuel pump but have never had to deal with this before
i just bought the truck last thursday
also my gas gauge is stuk at empty and the low fuel light is on
ANY HELP WOULD BE GREAT
my 2001 had two small vacuum hoses, about 1/4 inch ID and 8 inches long both get old, hard and crack.. caused the lean code. They are above the drivers valve cover on the EGR tubes i think. --- GAs gauge has power wire going to it with variable resistor in the tank and float. reistor changes with voltage make the gauge go up and down. Broken resistor in the gas tank, or wire to the gas tank will cause problem.
Welcome to the world of computers.
Leave the Seafom out.
There are no jets or carburator.
The Lean codes are likely an air leak into the intake area from some source such as rotted/ cracked hoses.
Check all the areas and hardware.
Seafoam won't help.
Your dealing with fuel tables that have been shifted to their lean side, setting the code.
It's an attempt by the computer to correct the fault that has gone to far out of correction.
The fuel gage is another issue. It could be the float stuck or sending unit faulty.
The dash is electronic and conducts the level corrections in time intervals. There could even be an issue in the dash system.
Generally a dash code quary might show a code to indicate the issue.
You would have to know how to trigger the dash diagnostics and interpet the result seen on the digital speedo display, of stepping through the tests.
You didn't post the codes which is most of the time better than giving a description, but you did post lean on both banks. If P0171 and P0174 the most common problem would be the 90 degree rubber boots on the PCV line. Another to look at is the line from the VMV next to the power brake booster that runs right next to the EGR valve.
hi i checked some of the vacume lines and i found 2 that were a bit corroded so i reeplaed them i also found another pipe (not quite sure what it was and replaced that also i then reset my codes and took it to work yesterday i got to work without any problems i thought i had fixed the problem as it only took 2 miles the last time for the service engine soon light to come on then on my way home the light come on again but i had drove a total of 20-25 miles before it come on any ideas why it took so long this time
my neigbour said he hs the same problem as i do and read it may be the EGR valve sticking any truth in this
thanks for the great advise so far
Thanks I found another rotted pipe after 20 mins of searching I replaced it and reset the codes again only for the light to come back on If I by a vacuum tester from o reilys will this help me find out if its a vacumm hose . Thank you very much for all the help so far these codes are driveing me nuts at the moment
It's questionable if a vacuum gage would be helpfull.
Each motor vacuum level depends on the state of the valve seal, cylinder seal etc and you don't have a reference to judge by.
Normally a vacuum of about 18 to 20 inches is a normal range and that can even change from day to day.
In the days before fuel injection, vacuum levels and how it reacted to throttle application was used as a diagnostic tool to judge the health of an engine for valve seal, ring seal, cylinder fireing pressure, cam lobe wear etc.
With the advent of FI, those ways are of limited value because it no longer has a carburator flow/draw to affect.
FI all but covers up a lot of these issues until something gets so bad it affects drivability or begins setting codes, then you have to do specific testing to uncover the causes.
What happens is the program tables have the designed in ability to shift there 'dynamic'' operating center over time to account of engine wear and parts wear.
The only time this changes is when you reboot the computer by removing power, then it starts all over from scratch.
What I often do is use a stethoscope with the tip remove to move around trying to detect a hiss sound that should not be there.
i checked every vacume hose in the engine i took them off cleaned themand put them back on i then tested them all with brake cleaner and nothing i also tested the EGR valve with the help of my neighbour who is a mechanic i think it is the MAF sensor as i heard this may cause the codes i put on a simlar MAF from his van and my trim reading went down to 26.7 from 29 .9 he told me they should be around 12 or lower just wanted to check with you guys as you have been so much help
many thanks wilky
OK i am finally getting peeved i bought a new MAF sensor and installed it i also replace the drivers side O2 sensors both upstream and downstrea as the Oreillys said this may also be a problem as it caused the same on her mustang the codes for running to lean are still comeing back on i drove maybe a total of 10 miles do i need to reset the codes and ake it for a longer drive or what it is really getting to me i cant think of what else it maybe
plase help any ideas or suggestions if i cant fix it soon i think i may just sell the truck and buy a differant one its driveing me nuts
Brother, you have a vaccum leak...its after the MAF which is why your still getting the Lean codes....the MAF sees "X" amount of air and tells the computer give "Y" amount of gasoline.....when you put air into the system AFTER the MAF, it does not read the amount so now you have "X" amount of air plus "A" amount of extra air. So, for a given amount of fuel "Y" you have too much air so your not getting the 14.4:1 ratio that efficient combustion needs. I would put money on the fact that you have a vaccum leak. My 99 had the same issue and I spent like $50 on just vaccum lines alone cause I replaced all of them lol. Just check, recheck, an double check bro, Its not as bad as you think...
You see, no one here suggested it was Ox sensors.
You spent money on parts trying the shotgun it. When it didn't work you get angry "at yourself".
You still have an intake leak at some point. Are the codes 171/174?
We are trying to steer you, so you have to keep looking to find what your missing on the air intake area.
Other places to inspect;
Dip stick tube and stick seal.
Throttle body bolts/gasket.
Rubber fittings out if sight that may be rotted.
Intake hose from the air meter to the throttle body.
Fuel regulator hose.
Plastic lines broken etc.
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