P0420 & P0430 codes: Catalytic inefficiency

Discussion in 'FJ Cruiser' started by BMThiker, Aug 10, 2012.

  1. BMThiker

    BMThiker I aim to misbehave SILVER Star

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    4,947
    Location:
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    So, I thought I'd share the little saga I've had with my FJC of late.

    Cliffnotes:
    I've been throwing P0420/P0430 (catalytic inefficiency right/left bank) codes since earlier this spring and now have to replace the exhaust manifolds.

    History:
    06/06 build date, purchased 07/06. 122,000 on the ODO. Daily driver and weekend wheeler (more like bi-annually these days:frown:). Heavily armored, meticulously maintained. Stock drivetrain except 4.56 gears and 35" KM2's. Never had a CEL come on before. Only overheated once or twice in the first year of ownership when radiator was blocked with mud (highest temp registered was 220). Stock air intake and exhaust - with only a minor modification to run the exhaust pipe behind the t-case instead of under it.

    Symptoms:
    I started throwing these codes every 500-600 miles earlier this spring. I asked around a bit and everyone said, "oh its just your O2 sensors behind the primary catalytic converters - a common Toyota problem. Just replace those and your CEL will go away."

    Diagnosis:
    When I replaced the O2 sensors ($100 each) the codes did go away for about six weeks. Ever since then, the frequency of the CEL coming on has increased. I've been scanning and resetting the codes with my ScanGaugeII. Usually it would only set off the left bank or the right bank at any time the CEL came on. I think once it registered both left and right at the same time.

    I've got to pass emissions next month. Now they come on every 30 miles or so which makes it impossible to pass the "readiness" test at the emissions center. The readiness cycle of your ECU is around 50 miles or so of mixed highway/city driving. Every time I delete the codes with the ScanGaugeII, it resets the readiness cycle of the ECU. If the ECU is not "ready", you fail the emissions test by default - kind of like a DQ in racing speak. The next test was to measure the temperature of the exhaust going in and coming out of the primary cat - done with an infrared/laser temp gauge pointed at the exhaust pipe before the cat and after the cat. If the cat is working properly it should be hotter (delta of 100* or so) from catalyzing the gases on the back side. Mine was reading an average of 650* in and 650* out. So that definitively narrows it down to the primary cats not working at all.

    Anatomy and Cure:
    The primary cats on the FJC are integrated into the exhaust manifold. No one makes a direct bolt on replacement other than Toyota. If I go aftermarket, then I'm skyrocketing my costs with JBA headers and Magnaflow cats. I ordered new manifolds and gaskets from Sam at Lowe Toyota on Monday and hope to have it all :wrench:'d out this Saturday.

    I'll update post surgery. If you're lucky, I'll even get a few pics of the procedure. :banana:
  2. 1911

    1911 chupacabra SILVER Star

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    Location:
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    How many miles on your truck Rick? I'm hoping my cats aren't plugging up or otherwise going bad. Good luck with the R&R; looks like tight quarters in there to get to the manifolds.
  3. holmanm

    holmanm

    Messages:
    80
    Location:
    Missouri
    --------------------------------------------------------------
  4. 1911

    1911 chupacabra SILVER Star

    Messages:
    3,270
    Location:
    Parker County, Texas
    LOL, yeah I guess I could have read with a little more comprehension!

    I've got 130,000 on mine so like I said, I hope the cats aren't going too.
  5. BMThiker

    BMThiker I aim to misbehave SILVER Star

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    4,947
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    The install went fairly smooth, roughly 5 hours under and over the engine bay. First thing to do is hose all bolts/studs with PB blaster or AeroKroil the night before and more the day you begin wrenching. I got the manifolds uninstalled in about two hours and realized I should have removed the front drive shaft first. It is necessary to make room for the manifold on the driver side to drop out the bottom. You also need to unbolt the flange at the back of the Y-pipe. This will allow the 2 foot section of pipe to be displaced while you wrangle out the passenger side manifold. Two socket sizes are used: 14mm with various extensions to disconnect the exhaust flanges and anchor brackets; and 12mm to remove 6 nuts on each manifold. I used a deep socket on a 3/8" drive for the manifold nuts. The longer your socket drive, the better for breaking them free, but a shorter drive is easier to maneuver the rest of the threads. Once the manifolds are loose you can access the O2 sensors' harnesses which require a strong squeeze of the clasp facing the firewall to unhitch. Once the manifolds are extracted use a 22mm wrench to swap them into the new ones.

    I think I spent more time removing my skids than I did removing the manifolds. Ditto on the installation process.

    Headed to the recyclers.
    Catalytic (1).jpg


    The new stuff.
    Catalytic (2).jpg


    All buttoned up.
    Catalytic (3).jpg

    tappity-tappity from my Android device
    Catalytic (1).jpg Catalytic (2).jpg Catalytic (3).jpg
  6. BMThiker

    BMThiker I aim to misbehave SILVER Star

    Messages:
    4,947
    Location:
    Atlanta
    a few more pics from the install...

    part numbers for gaskets - same #'s left and right.
    [​IMG]

    Soak in AeroKroil/PB Blaster and uncouple this flange on the passenger side. Also, leave all flanges loose until you get both manifolds into place on the block. I started to bolt this flange back too early and had to undo it again to get the pass side manifold to seat properly. You can also see the vestiges of my old Y that got relocated further back when I moved the exhaust pipe going under my t-case to go behind it.
    [​IMG]

    passenger side manifold going in
    [​IMG]

    my wife helping out
    [​IMG]

    Pass side in place
    [​IMG]

    Driver side in place. Now you can start bolting all the flanges together.
    [​IMG]
    You may notice the hanger bracket on this side is missing. I had to remove it when I replaced my starter earlier this summer and I sheared the bolt off in the old manifold when I tried reinstalling it after the starter went in. I have left it out for now because I honestly don't recall where I stashed the bracket. But the good news was that it was one less thing I had to move in order to wrangle the manifold in and out. I did not have to move the pass side bracket (truthfully I couldn't get it out), but it did require a little more muscle to get the manifold past it on both the extraction and installation.
  7. Sam Stewart

    Sam Stewart Kicking Boxes Supporting Vendor

    Messages:
    3,600
    Location:
    Atlanta
    No more CEL?
  8. 123ROBERTELEE

    123ROBERTELEE

    Messages:
    927
    Location:
    Baton Rouge LA
    Thanks for the pics and write up!
  9. BMThiker

    BMThiker I aim to misbehave SILVER Star

    Messages:
    4,947
    Location:
    Atlanta
    Put about 90 miles on it since Saturday night and, so far, looking good.
  10. Sam Stewart

    Sam Stewart Kicking Boxes Supporting Vendor

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    3,600
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    Awesome! :D

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