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O/T ford f 150 4.6

2K views 12 replies 6 participants last post by  12Gagejon 
#1 ·
TRON or Ford techs O/T ford f 150 4.6

I got a 99 f150 in today on a referral. Has a lean mix bank 1 and 2 codes P0171 172. Any way this truck has been through the mill. New MAF new O2 sensors fuel pump and filter tune up. What I found is on the back of the intake there is a servo the runs to a shaft going into the intake( I am assuming this is the wide open throttle valve actuator? Any way it seems to be pulling some vacuum through there? Is this normal or is there a limit to how much this may leak? any ideas
 
#4 ·
I don't know about no servo running to no shaft but I do know there is an elbow connected to a plastic tube that is connected to the PCV valve that likes to deteriorate and leak vacuum. This cannot leak at all or it will cause a lean condition. Replace the tube, available at your Ford dealer, and you will be fine

Steve
 
#5 ·
Are you sure that this is a 4.6 and not a 4.2.Is it a v6 or a v8.It sounds like you are describing a 4.2 v6 and these have the secondary throttle shafts you talking about.Yes they will leak a little but not enough to cause lean codes.check the pcv tube and connections closely. They are also know for intake gasket leaks.One other thing is their may be a pcm recalibration for this i cannot besure with out running a OASIS report.Have you checked fuel pressure to be sure it is in specs?And also the volume of fuel?If you get me the vin number i can run the OASIS and check for the possible recalibration.Let me know if i can assist you any more. Don Cummins
 
#8 ·
Problem solved, customer does not want to pay for time to check out. Love this crap he has dumped about 1800.00 into this thing. Is referred to me. I am by no means the fastest tech but eventually find the problem. Now he wants mr to wave the magic wand, poof fixed. Our shop is primary general repair. Brakes,suspension,maintainace ect. I will take on these "been everywhere but no one can fix" from time to time. dont know about you guys but info,wire diagrams, specialty tools are getty harder to get.
 
#9 ·
maclellan1911,I work in a Ford dealership.Have access to all ford service manuals,wire diagrams,ford technical hotline ect.We have mitchell on demand for other brand cars,and yes your right the aftermarket world of service info is very much lacking.They give just enough info to get buy if you are patient and willing to try.Also todays economy is as such that more people are coming in and wanting it checked out then say i will do it myself or i got a friend that will do it.Then they come back after it is hacked up and say you guys miss diagnoised it.For specialty tools try tooltopia.com or try rotunda.com for ford tools. Don Cummins
 
#11 ·
fordtech...I gave him nothing. My first boss taught me this. 40 i fix 50 i fix you watch 60 you fix i watch 100.00 you tried to fix now want me to fix it. I do not mind diag. for the DIY'er. As long as they pay. I told this guy I would look it over for 1hr@90.00. heck I found that leaking valve shaft in the rear with out trying. but like you said this is a unlikely source of the troubles. he's been chasing this lean mix for 1.5years now he's up for a emissions test this year. I know he will be back. With all that been replaced I have a funny feeling those lower gaskets are sucking air 175k on it Im sure they are as crumbly as peanut brittle! I also suspect the aftermarket O2's. We have had nothing but problems with the aftermarket parts ALL OF THEM. I have a new saying NEW MEANS NOTHING!
 
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