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Exhaust/tail pipe color

Discussion in '456/550/575' started by 166&456, Aug 21, 2011.

  1. 166&456

    166&456 Formula 3

    Jul 13, 2010
    1,720
    Amsterdam
    #1 166&456, Aug 21, 2011
    Last edited by a moderator: Sep 7, 2017
    I had a good run with the 456 today, a nice drive with fellow F-chatters across one of the country's nicest natural reservation areas. Was a very nice meet & drive.
    On the pictures I noticed that the left exhaust is looking very whitish, while the other is nice chocolate brown. I think this could mean it is running lean on the left bank? What do you think?
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  3. Mark456M

    Mark456M Formula Junior

    Aug 26, 2008
    562
    UK
    Full Name:
    Mark Hannaford
    The cat is on the way out.
     
  4. 166&456

    166&456 Formula 3

    Jul 13, 2010
    1,720
    Amsterdam
    #3 166&456, Aug 21, 2011
    Last edited: Aug 21, 2011
    Mark, can you explain how that would cause a whitish exhaust? Ceramic material exiting? There are no rattles or other signs of a cat problem.
    I searched a bit and found this thread where there seems to be inconclusion about the cause and it's seriousness - opinions vary between not to worry, cats and lean running: http://www.ferrarichat.com/forum/showthread.php?t=255948

    I will check the burn image on the spark plugs later this week to see if I can find anomalies there. If it's lean, what could be the most likely thing to cause it? Not the intake gaskets, those have been replaced recently. It's a 2.7 Motronic and it starts/drives great.
     
  5. Pong

    Pong Formula Junior

    Nov 5, 2003
    785
    Thailand
    Full Name:
    Pong
    You might want to check via SDII to make sure there is no fault. But it's good idea to worry for the worst but start checking from the easiest cause. It might be running lean at higher rpm. The cause, I have no idea!!??? You might want to go through the fueling system from the fuel filter upstream all the way to the injectors as well as checking the spark plugs. Other than that, I would consult the F-car mechanic for probable causes.
     
  6. Frari

    Frari Formula 3

    Nov 5, 2003
    1,186
    brisbane australia
    Full Name:
    tony
    I would think it is a cat deteriorating. I had similar on my 355
     
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  8. 166&456

    166&456 Formula 3

    Jul 13, 2010
    1,720
    Amsterdam
    #6 166&456, Aug 22, 2011
    Last edited: Aug 22, 2011
    I'll check it out, mostly worried about a problem with potential to damage the engine. I've read a few things about that the 2.7 Motronic can run lean sometimes and damage parts if it's pushed in that condition.
    I have never had a CEL warning on this car. I'll still check out the spark plugs.

    How urgent is this if it is the cat? Can I make it till the end of the season?
    It probably could eventually clog the exhaust?
    Thankfully they only sniff one exhaust side here at the yearly emissions and safety check funny enough. And usually the right one. :)
     
  9. PAP 348

    PAP 348 Moderator
    Moderator Owner

    Dec 10, 2005
    86,834
    Mount Isa, Australia
    Full Name:
    Pap
    Yep, my thoughts also. I only recently replaces a pair of cats because one had failed. (The same colour showing the tail pipe) The cat *crumbled* apart and it luckily blew it all out the tailpipe. :)

    I've never heard of the issue where the engine runs lean on the M2.7 in the 456.

    I would check the plugs on that side just for good measure.

    It *can* eventually break apart and get jammed in the muffler and/or block the exhaust. I had one years ago that actually blew the muffler apart. :eek:

    I thought it was just a normal case of back firing i.e-muffler can blow up or split.

    Only when I cut the front pipe section off the old muffler I saw parts of the cat wedged in there. I cut off the back half of the muffler and found melted pieces of cat convertor blocking around 90% of the outlet.

    I cut out and replaced both cats and the muffler. :)
     
  10. 166&456

    166&456 Formula 3

    Jul 13, 2010
    1,720
    Amsterdam
    Thanks Pap, good story, ok so no guarantees then it'll make it :)
    If it's the cats then can put on original OEM but at least one of the cats was replaced on this car about 30kkm ago (now 59k) so quality isn't great then, lasting 30kkm till failure?
    Thinking of going to metallic sportcats if that is the issue here. Anyone know if these are available? Hyperflow seems not to carry them. Or would an exhaust shop be able to put in universal racing cats? Hints, tricks, brands to use?
     
  11. PAP 348

    PAP 348 Moderator
    Moderator Owner

    Dec 10, 2005
    86,834
    Mount Isa, Australia
    Full Name:
    Pap
    The life of cat convertors varies. They should last the life of the car, but they dont. :D:D

    They fail because of other issues. Engine related, of course.

    I would visit your local exhaust shop and have them fit some universal high-flow cats. Would be cheaper than OEM and probably last longer too. :D:D
     
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  13. 166&456

    166&456 Formula 3

    Jul 13, 2010
    1,720
    Amsterdam
    Damn, could it be I caught that broken intake gasket too late? It had failed on that very bank.

    That I am pretty sure of. Shouldn't be too difficult for them to do and I can have the center resonator removed in the process :D.
     
  14. PAP 348

    PAP 348 Moderator
    Moderator Owner

    Dec 10, 2005
    86,834
    Mount Isa, Australia
    Full Name:
    Pap
    **** man, maybe. :(:(

    Good man, they will be able to sort it all out for you. :D:D
     
  15. joakim_adolfson

    joakim_adolfson Karting

    Sep 19, 2009
    156
    Stockholm, Sweden
    Check the fuel pressure as this is not measured on the 2.7. Mine are white on both banks and I found a black greasy mess in the intake under the fuel nozzles when I dismantled the intake runners. I guess mine has the rubber dissolve problem that many cars have.

    I'll get back with more analyses..

    that
     
  16. 166&456

    166&456 Formula 3

    Jul 13, 2010
    1,720
    Amsterdam
    Joakim, with the "rubber dissolve" problem, do you mean the rubbers holding the fuel pumps? That rubber doesn't dissolve, it crumbles into chunks that will never make it to the front so the black mess in the manifold probably had a different origin.

    The fuel pressure regulators were both renewed in the last service because one was found to be leaking. Measuring the pressure is on the list now.
    It used to rough start a bit when warm but drove it for about 3000km this year and that has completely gone away, it just purrs from the first turn of the key. Using something the way it was designed isn't a bad thing.
     
  17. joakim_adolfson

    joakim_adolfson Karting

    Sep 19, 2009
    156
    Stockholm, Sweden
    Hej,
    yes the rubber mounts, I do not believe this has anything to do with the cats it is most likely fuel oriented.
     

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