1999 5.4l Expedition PCV help

Discussion in '1st Gen - 1997 - 2002' started by Cbaker91, Dec 6, 2018.

  1. Cbaker91

    Cbaker91 New Member

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    I went to AutoZone and had my CEL codes scanned. The employee hooked the reader up to their computer and told me the CEL came on because of my PCV valve.

    The valve that is currently on there is only 4 months old so I assumed it was the grommet (because of age and because the pcv valve just slides out with barely any resistance or effort) and tubes/hoses (they looked incredibly aged and dry rotted plus was pieced together with broken pieces of plastic tube and rubber hoses and connects the PCV directly into the side of the throttle body where the coolant lines branch. After doing some research and poking around, I found that the PCV valve hose assembly is also supposed to go into the back of the throttle body/Intake manifold. After feeling around, I found the nipple it's supposed to connect to, but it has been capped off.

    So I've been stuck wondering a few questions.
    Could the new PCV valve be bad so fast?, it still rattles fine.

    Could the CEL and code be caused by the old grommet and hoses?
    How tight should the PCV valve fit into the grommet?, because the current one just seems lose to me.

    Why would the previous owner have capped off the back PCV nipple and is that bad or could there be a good reason for it?

    Are aftermarket PCV valves worth it or stick to the motorcraft ones?

    One of the coolant lines that branches from the side of the throttle body where the PCV hose connects leads to where the air intake meets the throttle body and hooks Into the side of a random plug? Can anyone tell me what the plug is?

    Thanks ahead of time for any help or Info guys.

    IMG_20181205_111310.jpg IMG_20181204_163849.jpg IMG_20181204_163842.jpg
     
  2. 1955moose

    1955moose Full Access Members

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    As to your question, can a new one be bad even though it rattles, sure. Maybe it's not sealing. Their cheap enough, go buy a Ford one, and Ford grommet. I'd also change all the hoses around it. Most common vacuum leak and 2 codes 071, 074, usually stem from one of the hoses. See if you can get a printout, or better still pictures of where all the hoses go, taken from another early first edition 5.4. I've seen so much Mcgyver jury rigging on hoses and wiring over the years, it would fill a book. The lengths some individuals go through just not to fix a job correctly, never ceases to amaze me.

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  3. Tonyray

    Tonyray Active Member

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    It's probably not the valve but the hose that's the problem. Amazon has them for $30.00 part number XL3Z-6C324-GA and it also comes with a new PVC valve too. you can find a new rubber grommet at Autozone for a few bucks.
     
  4. mrphixit

    mrphixit New Member

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    I have a 99 expy with the 5.4L and I have had to change that PCV line setup. When it develops a leak at the rear of the throttle body you'll get a code ( sorry, I don't remember the number) and engine idle will be very rough if it runs at all. My guess as to why someone would have capped it would be that the pcv hose assy was somewhere around the $80 range and it is a pain in the ass to change without removing the throttle body. (almost impossible). Is there a disc about the size of a quarter and about 1/2" thick on the side of the throttle body that the coolant lines attach to (1 in front and 1 in back) and the pcv hose goes into from the side? The reason I ask is because on mine that disc blew a hole on the inside and allowed coolant to be sucked into the intake manifold. As soon as it happened gray steam started billowing from my exhaust. It acted like a blown head gasket, so I took compression readings and #3,#4 cylinders were way down. Others were all fine at the time so I changed the head gasket on the passenger side even though nothing appeared to be wrong with it upon disassembly. It ran fine for about 10 miles and the same thing happened again, only this time all of the cylinder compressions were bad. Every post I read and every mechanic I talked to about it including the Ford mechanic at the dealership said it was an intake manifold gone bad allowing coolant to be sucked into the plenum and right into the cylinders. What I couldn't understand was why there was coolant in the bottom of the intake.. I could see it by looking down through he throttle body. It turned out that it was there because it was being sucked in by the vacuum. And apparently, because it sat for a few days before I reassembled it the hole gummed itself closed temporarily. The easy fix was to bypass the disc with the coolant lines, connect them directly to each other, and cap the 2 nipples with a small piece of hose from one nipple to the other. I hope you never have this problem, but if you do....check that disc.
     
  5. 98eb5.4

    98eb5.4 Full Access Members

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    what code(s)? if u don't know = waste of time
     

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