355 Spark Plugs. Help? | FerrariChat

355 Spark Plugs. Help?

Discussion in '348/355' started by Manuel, Mar 16, 2007.

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  1. Manuel

    Manuel Rookie

    Oct 19, 2004
    41
    San Juan,Puerto Rico
    Full Name:
    Manuel del Valle
    #1 Manuel, Mar 16, 2007
    Is it normal to expect frequent (every 2,000 miles) spark plugs replacement for a F355 usually driven in traffic and/or relatively slowly (80 to 90 mph)? I have tried NGK 6A and 7A. Both NGK plugs lasts about the same before the car starts to misfire (particularly between 3K and 4K rpm). Every time I fill up the fuel tank, I also add a bottle of Techron. Although it seems to help, I have gone thru 4 sets of spark plugs in the past 9,000 miles. The car has 20,100 miles. The car has installed Kingsborne spark plugs cables, Tubi exhaust manifolds, Hyper Flow Cats and Tubi muffler. Otherwise is stock. I am planning on trying Brisk spark plugs. Any suggestions?
     
  2. Rifledriver

    Rifledriver Three Time F1 World Champ

    Apr 29, 2004
    34,010
    Austin TX
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    Brian Crall
    #2 Rifledriver, Mar 16, 2007
    I use nothing but NGK plugs. Ferrari finally switched to them as well. If you are not getting 30k miles of perfect performance from them something else is wrong.


    6's are too hot. You should have 7 or 8's in it.
     
  3. Ricambi America

    Ricambi America F1 World Champ
    Sponsor Owner

    Dec 7, 2003
    16,248
    Winston Salem, NC
    #3 Ricambi America, Mar 16, 2007
    ^^ Brian, this is a good observation. I am perpetually confused about which plug is correct for the various F355's. I assume PMR7A is only valid for the 1995 F355's, then switch to the PMR8A for 96-99 (which is also used on 360's). Is this your usage too?
     
  4. f355alldaylong

    f355alldaylong Karting

    Jan 24, 2005
    52
    South Carolina
    #4 f355alldaylong, Mar 16, 2007
    pop up a pic of the plug, if you can. are they oil fouled, by chance?
     
  5. Rifledriver

    Rifledriver Three Time F1 World Champ

    Apr 29, 2004
    34,010
    Austin TX
    Full Name:
    Brian Crall
    #5 Rifledriver, Mar 16, 2007
    According to the NGK catalog I have (bad source actually) they only list the 8 for 95 GTS? I haven't seen a problem with either but would certainly prefer the 8's if I was using the car very hard.
     
  6. Manuel

    Manuel Rookie

    Oct 19, 2004
    41
    San Juan,Puerto Rico
    Full Name:
    Manuel del Valle
    #6 Manuel, Mar 16, 2007
    What else do you recommend I check for? The car is a 98 model. What I dont understand is why (assuming the plugs are good) the car misfires a little between idle and 2K rpms and more pronounced between 3K and 4K rpm but not above these rpm ranges. Any suggestions?
     
  7. Rifledriver

    Rifledriver Three Time F1 World Champ

    Apr 29, 2004
    34,010
    Austin TX
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    Brian Crall
    #7 Rifledriver, Mar 16, 2007
    Check the compression, the ignition system and the fuel system.
     
  8. BadHorsie

    BadHorsie Karting

    Feb 6, 2005
    71
    Nevada
    Full Name:
    Steven Verwer
    #8 BadHorsie, Mar 16, 2007
    Can you post close up pics of your plugs? (I always number mine when I take them out) There might be some obvious reasons your having problems that can be seen by their condition.
     
  9. No Doubt

    No Doubt Seven Time F1 World Champ

    May 21, 2005
    72,740
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    Mr. Sideways
    #9 No Doubt, Mar 16, 2007
    I would helpfully suggest that you read your spark plugs to help learn what is going on: http://www.ferrarichat.com/forum/showthread.php?t=121401
     
  10. DMOORE

    DMOORE Formula 3

    Aug 23, 2005
    1,720
    San Diego
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    Darrell
    #10 DMOORE, Mar 16, 2007
    In any modern EFI car, spark plugs should last many thousands of miles. Your plugs are only a symptom of something else not right with the car. 4 sets in 9000 miles is simply not normal. I would suggest you have a experianced Ferrari tech check it out.


    Darrell.
     
  11. F355Bob

    F355Bob Formula 3

    Nov 4, 2003
    1,999
    Madison, Wisconsin
    #11 F355Bob, Mar 17, 2007
    What year is your F355? I have a 95 and they are prone to foul plugs because the start up is rich. If you start your car for a short time and shut it off, like just backing it out of your garage, you will foul a plug. This has happened to me and others with 95's. You need to let the car run until it is warm--fans turn on-- before you shut it off.
     
  12. Manuel

    Manuel Rookie

    Oct 19, 2004
    41
    San Juan,Puerto Rico
    Full Name:
    Manuel del Valle
    #12 Manuel, Mar 22, 2007
    Thank you all for your comments. The car is at the shop and the spark plugs were removed. Although they do show some abnormal carbon deposits, there is no trace of oil. Nevertheless, a couple of plugs show rust on their body shell (not on the elctrode). As per the mechanic, its apparent water (probably from washing) got between the cylinder head cover and the smaller cover above the spark plugs. Hopefully the cables are OK. Lets see.
    As a bonus, the by-pass tubes heat shield was also found "broken".
    The joys of Ferrari ownership!
    But, as we all know, when you get the car in perfect condition, all is forgotten.
    Thanks,
    Manuel
     
  13. No Doubt

    No Doubt Seven Time F1 World Champ

    May 21, 2005
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    Mr. Sideways
    #13 No Doubt, Mar 22, 2007

    Your Kingsborne spark plug cables are guaranteed forever. Free replacements.

    That being said, rust with 2,000 miles on your plugs speaks of very little driving over a long period of time (or an undiagnosed problem).
     
  14. f355spider

    f355spider F1 World Champ
    Owner Rossa Subscribed

    May 29, 2001
    17,938
    USA
    #14 f355spider, Mar 26, 2007
    You need to be sure and order new gaskets for the cam covers! They are (I think) paper, and also the new foam pieces at the end of the cam covers where the spark plug wires come out of the covers. This is the only way to ensure you don't have water intrusion again. I would go ahead and order new plug wires, they are known to fail after a few years.

    You can get reasonably priced replacements, using factory Beru brand connectors on each end for less than $250 here: www.kingsborne.com Just make sure and specify that you want oem sized 7mm wires, NOT the 8mm. 8mm can be a real pain to fit as the spaces in the cam covers where designed for the 7mm.
     
  15. taz355

    taz355 F1 Veteran
    Owner Silver Subscribed

    Feb 18, 2008
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    Indio Ca/ Alberta
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    Grant
    #15 taz355, Apr 22, 2018
    As stated by Rifledriver
    Pmr8 in 1995
    Pmr7 in 1996-99
     

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