If you have an 01+ 4.0 with lean codes (PO171 and/or PO174) look here!
These two codes normally indicate a vacuum leak. a vacuum leak can be caused by a number of things but the most common cause in the 01+ SOHC 4.0L is a cracked PCV vacuum line elbow. so if you have one or both of these codes popping up check this out first.
the elbow is located just to the left of the throttle body just under where the upper radiator hose snakes around the oil fill, grab that hose and pull it over the oil fill http://i26.photobucket.com/albums/c1...s/103_2332.jpg http://i26.photobucket.com/albums/c1...s/103_2333.jpg That will uncover the elbow so you can see it better. (mine looks a little different because its been replaced before) http://i26.photobucket.com/albums/c1...s/103_2331.jpg the stock elbow will look like this http://i26.photobucket.com/albums/c1...pics/Hose2.jpg http://i26.photobucket.com/albums/c1...pics/Hose1.jpg now that you have located the elbow pull it off of the lines its attached to and examine it for cracks or holes. Now if you determine that the elbow is bad you have a couple options to fix it. The first and most expensive option would be to buy an OEM replacement elbow that costs about $15.00 from Ford (part# F8UZ-6762-AA) or you could do as i did and go to the local auto parts store and pay a couple bucks for about 6" of 5/8" ID gas and oil safe rubber hose. Trim it to length if needed after a test fit and install it. I didnt use hose clamps to hold mine on because the rubber hose fit snuggly over the lines but you can use them if you wish. Once that is done dont forget to put the upper coolant hose back where it is supposed to be, disconnect the battery or use your code scanner to reset your check engine light and your done! If anyone would like to add any additional pics or tips to this thread feel free. |
Re: If you have an 01+ 4.0 with lean codes (PO171 and/or PO174) look here!
Great info seems to be a common problem
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Re: If you have an 01+ 4.0 with lean codes (PO171 and/or PO174) look here!
Sweet buddy thanks for the help!
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Re: If you have an 01+ 4.0 with lean codes (PO171 and/or PO174) look here!
Awesome, I had a huge gash in mine. Thank You very much for the help!
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Re: If you have an 01+ 4.0 with lean codes (PO171 and/or PO174) look here!
Very cool write up!!
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Re: If you have an 01+ 4.0 with lean codes (PO171 and/or PO174) look here!
mine occassionally throws the code for "Vaccum System small leak" or something like that. It only started after I did the body lift. I figured it was something to do with the filler neck modification
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Re: If you have an 01+ 4.0 with lean codes (PO171 and/or PO174) look here!
Great write up. Did not work for me as my elbows looked good back and front. What is the best way to check for vac leaks? I have read carb cleaner. Anything else that might set off these codes?? Thanks!!!!
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Re: If you have an 01+ 4.0 with lean codes (PO171 and/or PO174) look here!
Mine just threw the codes for lean bank 1 and 2, mechanic said it might be the CAI with it all of a sudden getting colder out, the colder denser air may effect it.
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Re: If you have an 01+ 4.0 with lean codes (PO171 and/or PO174) look here!
Dude I have a CAI and no codes, I dont think it could be that after thinking about it
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Re: If you have an 01+ 4.0 with lean codes (PO171 and/or PO174) look here!
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Re: If you have an 01+ 4.0 with lean codes (PO171 and/or PO174) look here!
you check that 90 intake hose?
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Re: If you have an 01+ 4.0 with lean codes (PO171 and/or PO174) look here!
yea mine threw them their codes and i checked the pvc and had to plug the end of the plastic fitting, I have just changed it but forgot that the aftermarket ones have a second plastic end that needs to be plug, WALLA!
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Re: If you have an 01+ 4.0 with lean codes (PO171 and/or PO174) look here!
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Re: If you have an 01+ 4.0 with lean codes (PO171 and/or PO174) look here!
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Re: If you have an 01+ 4.0 with lean codes (PO171 and/or PO174) look here!
I just fixed it, here's what mine looked like:
http://i590.photobucket.com/albums/s...4/IMG_1639.jpg |
Re: If you have an 01+ 4.0 with lean codes (PO171 and/or PO174) look here!
See that....Cold air intake problem my ass!!
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Re: If you have an 01+ 4.0 with lean codes (PO171 and/or PO174) look here!
In the words of "The Count": "Ah... Ah... Ahh"
I still want to go back to stock |
Re: If you have an 01+ 4.0 with lean codes (PO171 and/or PO174) look here!
Good god!! Really?
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Re: If you have an 01+ 4.0 with lean codes (PO171 and/or PO174) look here!
Indeed
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Re: If you have an 01+ 4.0 with lean codes (PO171 and/or PO174) look here!
Here's another thing you could do asweel is get the meshing like what is over the big hose and put it on that elbow and it won't wear through as fast
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Re: If you have an 01+ 4.0 with lean codes (PO171 and/or PO174) look here!
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Re: If you have an 01+ 4.0 with lean codes (PO171 and/or PO174) look here!
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Re: If you have an 01+ 4.0 with lean codes (PO171 and/or PO174) look here!
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To the OP-you are the King!! Thanks for posting all the great pics. I am not very skilled in the mechanical department, but this was my problem as well and your step-by step solution was a Godsend as I was about to spend about $300 on a new MAF sensor.
I have an '03 Mazda B4000 and about 2 weeks ago the CEL came on. Took it in to the mechanic, who replaced the fuel filter (which it needed anyways). The first time around he did the smoke test and found no vacuum leak as he was certain there would be a leak somewhere. He also believed all the O2 sensors were fine and cleaned the MAF sensor as well, which led him to the fuel filter. Within a day or two, the CEL returned when my wife was driving it. The second time around I had it back to him, he still could not find the issue; he is also a very reputable mechanic where I live so he cleared the codes and the next day, CEL on. He advised me if the light came back on, which it would, it probably was the MAF sensor going. The truck was running fine-no misses, stalls, hisses, lack/loss of power or anything. He had told me what the codes were and with a little help from good old Google I found this site. This morning, I found the problem (same as noted above) as there is 3/4" gash on the topside of this infamous elbow. I replaced it with braided heater hose from NAPA ($1.69/ft for the high end stuff) as per the OP's advice and in about 10 minutes, I had replaced it. I followed all the steps as the OP suggested to do, then took it for about a 20 mile test drive and no CEL. Here is the gash in my PVC elbow; I had to cut the end closest to the throttle body as it was welded on there pretty good (the cut in the bottom edge) from years of service. Thanks again for the solution to such a simple (but annoying) fix!! Feeling pretty good about myself that I was able to fix something a mechanic with 20 years experience was unable to-haha. |
Re: If you have an 01+ 4.0 with lean codes (PO171 and/or PO174) look here!
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Re: If you have an 01+ 4.0 with lean codes (PO171 and/or PO174) look here!
my ranger has kicked thos codes since it had about 80 k on it. I havent done anything but now im have a problem with my number 3 plug fouling.my head gaskets are leaking.and i have to replace the plug every 500 miles. Are there any quick fixes for his problem.I just need to get another 30 k out of engine.
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Re: If you have an 01+ 4.0 with lean codes (PO171 and/or PO174) look here!
My 2002 explorer with the 4.0L in it just threw these codes so I was looking under the 4.0L forums and I see the codes that it poped and I was reading this so I go run outside and my mom is like what are you doing, Any who, It was cracked. I had some smaller hose but I just heated the hose and made it fit for now till I get around to fix it, But thanks to this thread no more rough idle
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Re: If you have an 01+ 4.0 with lean codes (PO171 and/or PO174) look here!
I have a 2001 Ranger 4.0 and had the 2 codes and just went out and looked and yup the elbow has a big gash in it. Now just have to go out and get a piece of hose to fix it. Will this possibly help with the rough idle I have? It seems to be fine when driving any speed just when idling it will idle rough and sometimes even stall and the engine will shake a little. Seems to be worse after the engine as warmed up.
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Re: If you have an 01+ 4.0 with lean codes (PO171 and/or PO174) look here!
mine does that from time to time especially when the heat is on, but you will notice a slight difference
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Re: If you have an 01+ 4.0 with lean codes (PO171 and/or PO174) look here!
You say 5/8" hose fits snug, how snug? A store near me has 19/32" hose which I would assume will fit since it is only 1/32" smaller then 5/8".
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Re: If you have an 01+ 4.0 with lean codes (PO171 and/or PO174) look here!
get both and see which is the better fit. Its cheap enough
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Re: If you have an 01+ 4.0 with lean codes (PO171 and/or PO174) look here!
Well I replaced the elbow with the 19/32 hose and it fit good. I let it get up to normal engine temp and so far it seems to idle fine and the CEL hasn't come on after I reset it but will have to see when I can drive it longer and see how it does.
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Re: If you have an 01+ 4.0 with lean codes (PO171 and/or PO174) look here!
Excellent! Good news!! Glad to see you corrected it!
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Re: If you have an 01+ 4.0 with lean codes (PO171 and/or PO174) look here!
Well after driving to and from work today even with driving home in a snow storm with stop and go traffic my Ranger did great. The CEL hasn't come back on and the engine never stalled or had rough idling while at a stop or going really slow. I think fixing the elbow did the trick and probably saved me a bunch of money not having to bring it in to get looked at.
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Re: If you have an 01+ 4.0 with lean codes (PO171 and/or PO174) look here!
Good deal!!! Glad to hear you're all set!
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Re: If you have an 01+ 4.0 with lean codes (PO171 and/or PO174) look here!
Thanks guys, I checked the elbow, it is fine. I have a guy that will change the fuel pump for 80.00 if I buy the parts, I think that is a fine deal. We tested to see if there was gas from the pump. there was none. I am hoping that is the problem. The only thing that concerns me is that is could be a faulty security system, but the truck has 129K miles on it, and never had a new pump. So here's crossing my fingers.
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Re: If you have an 01+ 4.0 with lean codes (PO171 and/or PO174) look here!
That sounds like a good deal!
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Re: If you have an 01+ 4.0 with lean codes (PO171 and/or PO174) look here!
That was great info. That could be what is going on with my '97. I have had those codes come up and makes perfect sense. Will have to check that out. Thanks.
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Re: If you have an 01+ 4.0 with lean codes (PO171 and/or PO174) look here!
Check your gas cap
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Re: If you have an 01+ 4.0 with lean codes (PO171 and/or PO174) look here!
Everyone should check theirs just because!
I didn't have any code but mine was cracked. |
Re: If you have an 01+ 4.0 with lean codes (PO171 and/or PO174) look here!
I have a 2001 Ford Ranger 4x4 X-cab 4.0. It has 150k miles on it. I had a tune up completed last week, and this weekend the engine light went on. I took it back to the shop and they told me the CEL was due to code 171. They wanted to change all of the O2 sensors.
I found this post after doing a few searches. I told them not to do any work on the truck. On my way home I purchased the recommended 5/8 inch hose and made the fix. If it was not for the post, I would be out $400 instead of the $10 I paid for the hose and clamps. Thanks! |
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