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3 Catalytic Converters?

Discussion in '1st Gen - 1997 - 2002' started by Ulver, Jun 15, 2019.

  1. Ulver

    Ulver Full Access Members

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    Hello all, I own a 2001 Ford Expedition 4.6 2wd, and I'm a little confused.

    This car was purchased with cat inefficiency codes when I bought it from the previous owner. So I'm looking to replace the two front cats. What I thought I was going to find was 4 cats in total, but instead I found 3. One on the passenger side, and 2 on the drivers side. Alldata gives the a part that has 4 cats, but I only have three. Perhaps I need to go look again, but I'm pretty confident there are only three.

    Does it not matter, as long as there's a functional catalytic converter in between the o2 sensors, and that I should't worry? The entire unit looks original, but I could be wrong. Thanks in advance.
     
  2. Maximus

    Maximus Active Member

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    This is strange, I can attest that all 1st Gen Expys came with 4 Cats, 2 Front Bends (that come almost directly off the Exhaust Manifolds) and 2 "Fat Bois" directly behind the bends but before the Y-Pipe. Could you specify which one is missing? Front or Rear Passenger Cat? You could also get a shop to wipe the code if need be.

    In addition if you're gonna replace the fronts, I would recommend replacing the rears as well, as you'll have a tonne of extra exhaust buildup on the secondaries which could end up with another check engine Light.
     
  3. Ulver

    Ulver Full Access Members

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    You're right, I'm going to need to replace the secondaries while I'm at it. It would be a big risk to do all of that, and to find out that I still have issues.

    I double checked, and yes, I have 2 on the drivers side, and 1 on the passenger side. I looked all the way up to the exhaust manifold on the passenger side, and the front bend is missing. I only have one big boy on the passenger side.

    I was thinking, since I only have that 1 on the passenger side, I could cut it out with a pipe cutter and replace and clamp it. The drivers side will have to be completely replaced.
     
  4. Maximus

    Maximus Active Member

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    If you're gonna go through that much trouble cutting and replacing each one individually, all the power to you. But I'd humbly suggest just grabbing a Direct Fit CAT System, Comes with the both sets of CATs with the connected piping that make the Y-Pipe. Flowmaster has a great CAT system that's relatively inexpensive compared to other Catalytic Kits. You can buy one side or both, works either way. Less work for you plus the benefit of having brand new pipes connected the rest of the Exhaust and not having to worry about buildup.
     
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  5. Ulver

    Ulver Full Access Members

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    I think I'll go with the direct fit route. Purchasing the left and right and getting it over and done with. Are these compatible? The website for the first link says no, but I've seen references to it from older threads.

    Driver side -- https://www.amazon.com/Flowmaster-2020014-Outlet-Catalytic-Converter/dp/B00BQ9UWMA/ref=au_as_r?_encoding=UTF8&Make=Ford|54&Model=Expedition|662&Year=2001|2001&ie=UTF8&n=15684181&newVehicle=1&s=automotive&vehicleId=1&vehicleType=automotive

    Passenger side -- https://www.amazon.com/dp/B00BQ9UWO...2b-11e9-9d02-b33be0c06c26&smid=A2UUWCCR4G5EFA
     
    Last edited: Jun 26, 2019
  6. Ulver

    Ulver Full Access Members

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    So this weekend I've officially completely my last (known) major job. Replaced both passenger side and driver's side direct fit catalytic converters, and now the post o2 sensors are at a good flat line, and I passed the smog test on my reader. All codes are now cleared. Aaaah that great feeling of accomplishment. My body still kind of hurts from rolling all over the concrete, but it was worth it.

    If anyone needs any advice on this project, feel free to ask.

    Now, moving on to aesthetics.
     
  7. 2WD99

    2WD99 Member

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    I have a 99 two-wheel drive with the 4.6. flowmaster part numbers you provided are listed as being for four wheel drive. Were you able to use them on your two wheel drive without any issues?
     
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  8. Ulver

    Ulver Full Access Members

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    Yes, everything fit well for my 4.6 2wd except for the bracket that's circled. The hole of that bracket and the mounting area underneath are misaligned but it's okay. Everything stays up, and nothing hangs. No problems so far after almost 2 years. You can always use something (maybe a hanger?) to feed through the hole of that bracket and lock it into place. Not really a big deal if you don't.

    P.S. An exhaust pipe expander is needed for this job for fitting the pipes together. You can rent one from an auto parts store.
    6154LFP-Q6L._AC_SL1500_.jpg
     

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