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348 Noise & Question for Brothers

Discussion in '348/355' started by FandLcars, Feb 23, 2008.

  1. FandLcars

    FandLcars F1 Rookie

    Aug 6, 2006
    3,043
    Tempe, Az
    Full Name:
    Rick Schumm
    Hi Guys - Hope you don't mind a kind of long discussion on a noise I discovered on a 348TS I bought last month in North Carolina. Today, I decided to do my first 348 troubleshooting & find cause of the noise. When I bought the car in North Carolina, the car was warm the whole time that I inspected it. It was loaded on the transport 90 min or so after that. I suppose it's possible that the car was also warm when the PPI was done, since the PO dropped it off at the shop during the day. A noise or a problem was not mentioned after the PPI.

    However, when the trucker started the car here at my place and unloaded it, we both were surprised to hear a noise that hadn't been there in North Carolina. I've discovered the noise is there on a cold start, and then abruptly shuts off after warming up a while. After warm, it also seems to be there when briefly on a restart for a second or two. So it seemed both temperature dependent, and vacuum-dependent (ie, when warm shuts off shortly after starting).

    After checking the shop manual, it seemed that the exhaust "secondary air" or exhaust air injection fit in this category. Sure enough, when testing today, if I pull and plug the vacuum lines to the actuating valve on each bank, the noise disappears, and reappears when I reattach the vacuum lines to the actuating valve on each bank. So that's the source of the noise... seems to be at the check valves/ "stop valves" in this circuit by the headers. Sounds kind of metallic, and REALLY un-Ferrari-like.

    So my question is how much noise do other 348 Brothers get from this system during warmup, is it the check valves, and do they periodically have to be replaced to limit noise? If not, what is the source? I'm almost embarrased to have other Fcar owners hear my car when cold or initially starting it. It's louder than I would expect for a system like this.

    Any experience or advice appreciated.

    Thanks!
    Rick
     
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  3. Miltonian

    Miltonian F1 Veteran

    Dec 11, 2002
    5,964
    Milton, Wash.
    Full Name:
    Jeff B.
    The noise is probably 100% normal. It's part of the air injection / pollution control system. As long as it goes away once the engine is warmed up, I wouldn't worry about it at all. The only problem is that if the "non-return valves" go bad, you get exhaust pulses going up into the tubes, and this can potentially melt the "cut-off valves".
     
  4. No Doubt

    No Doubt Six Time F1 World Champ
    Consultant

    May 21, 2005
    67,323
    Vegas+Alabama
    Full Name:
    Mr. Sideways
    Those 1-way valves are generic cars parts. You can buy the Ferrari version...or you can buy the generic version for $5 each to end that noise (or you can weld the old ones shut).

    They heat up the cats faster at startup, and provide extra air at idle to help you pass emissions tests.
     
  5. Delphia37

    Delphia37 Karting

    Feb 22, 2008
    56
    Vancouver, BC
    Full Name:
    Don
    Hi Rick,
    I know the exact noise that you are talking about as a recent first time Ferrari owner it also kind of took me by surprise the first time i heard that 'racket'! You are right... it does not sound very Ferrari-like during that (thankfully) brief warm up period. As someone previously mentioned i was told that it had something to do with the pollution equipment.
    Now you can breath a sigh of relief.
    Have fun!
    Don
     
  6. Chris Honeywell

    Chris Honeywell Karting

    Nov 11, 2007
    98
    Trowbridge UK
    Full Name:
    Chris Honeywell
    It is perfectly normal, it reduces emmisions at start up and pumps warm air back into the intake to aid warm up:)..

    mine is on for a good 5 mins at start up
     
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  8. potxoli

    potxoli Formula 3

    Mar 22, 2007
    1,716
    Washington DC
    Full Name:
    Eric B.
    can someone post a picture of this valve? First I've heard of it for 348s and my car doesn't make any noise, but then again I have tubi and hyperflows so I don't know if that makes a difference
     
  9. Dean355

    Dean355 Formula 3

    Sep 4, 2006
    1,101
    South Florida
    Full Name:
    Dean
    Perfectly normal. Mine does it for about 5 minutes at cold start, then goes away.

    No worries.
     
  10. F512M

    F512M Formula Junior

    Dec 9, 2003
    504
    Houston, TX
    Full Name:
    Jeremy Lawrence
    Perfectly normal as many have already stated.


    I had that problem last year. Easy fix. Link below has a photo of the melted check valve and PN#'s for replacement non-return valves.

    http://ferrarichat.com/forum/showthread.php?t=142985&highlight=f512m
     
  11. modena2904

    modena2904 Formula Junior
    Silver Subscribed Owner

    Jul 6, 2007
    914
    Ellicott City, MD
    Full Name:
    Eric
    My car also makes a slightly different sound when cold -- I believe it is normal. I also have noticed that the noise stops if RPMs exceed somewhere around 4000.

    - Eric
     
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  13. FandLcars

    FandLcars F1 Rookie

    Aug 6, 2006
    3,043
    Tempe, Az
    Full Name:
    Rick Schumm
    #10 FandLcars, Feb 24, 2008
    Last edited by a moderator: Sep 7, 2017
    Thanks everyone! I've attached a couple pics of the components. Pics are for left bank (same on right bank). One pic shows electric solenoid valve that the ECU actuates to start the air flow to the exhaust between 59 and 122 deg. F coolant temp.... this solenoid is the brass thing just to the left of the black oil filter. Second pic shows the black air flow on/off valve that opens when the solenoid actuates and sends vacuum to the on/off valve. Third pic shows 2 air flow check valves at the front of the engine, just above the headers. Again these are duplicated for the right bank.

    So the easy way to eliminate the noise would be to either remove and plug the vacuum line at the on/off valve, or remove the electrical connector to the solenoid, for both banks. I don't see a problem doing this, other than increase in warmup emissions. Hope this info helps.
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  14. MaterMech

    MaterMech Formula Junior

    Feb 26, 2007
    476
    Los Gatos CA
    Full Name:
    Mark Johnson
    What's the problem with the noise? I would just leave it as installed! Plus have you noticed how good it sounds at wide open throttle with that system still functioning! It should not sound metalic and maybe one of the check valves is coming appart. Compare the noise from one side to the other. People here emissions control and imeadiatly start thinking of what is being lost. This system is lossless so no sense welding things closed or such, as I've seen many geniuses do.
     
  15. ernie

    ernie Two Time F1 World Champ
    Lifetime Rossa Owner

    Nov 19, 2001
    22,063
    The Brickyard
    Full Name:
    The Bad Guy
    Leave it hooked up. They are only on for a few minutes until the water temperature reaches the desired number, then they close.
     
  16. FandLcars

    FandLcars F1 Rookie

    Aug 6, 2006
    3,043
    Tempe, Az
    Full Name:
    Rick Schumm
    Well, one reason is that it doesn't sound like a Ferrari noise. Also, people (like me until I learned better), will wonder what's wrong with my car, since the 328s, TRs, etc. at gatherings don't sound like that. The noise is the same, left or right side.

    Thanks for all the input guys. I like keeping cars original, but since this system has little benefit except while idling and warming up, I think I'd rather disable it than have the noise. It's also something else to have to fix if something breaks.

    EDIT : Should add that I'll be doing a major in March, and I'll take a look at the check valves, and if they are junk, I may decide to replace them first and see if it improves a lot, before disabling the system.

    Thanks again ;)
    Rick
     
  17. MaterMech

    MaterMech Formula Junior

    Feb 26, 2007
    476
    Los Gatos CA
    Full Name:
    Mark Johnson
    Neither does the stock exhaust :) How long does the noise persist? It should not last longer than about 2-4 mins in AZ.
     
  18. FandLcars

    FandLcars F1 Rookie

    Aug 6, 2006
    3,043
    Tempe, Az
    Full Name:
    Rick Schumm
    Good point on the exhaust! ;) That's why I had already made up my mind to change the exhaust later this year. Right - the noise only last a couple minutes. But for a couple-hour event, bummer to have a noise like that. I can hear it now.. "Hey, did you put a diesel in that thing?" ... Ok, not really that bad. :)
     
  19. tamf328

    tamf328 Formula Junior

    Mar 9, 2005
    477
    My 348 does that, when cold for a few minutes until it warms up.
    I think it's part of the emissions system. Its kind of a gurgling sound
    one bank usually stops first. It never happens when the temp or the car
    is warm.
     
  20. Kaivball

    Kaivball Three Time F1 World Champ
    Owner

    Jan 11, 2007
    35,882
    Kalifornia
    I've had that stupid check valve fail TWICE in a month and had to replace that single/dual rubber hose. Cost new for the hose: $800!!!

    After the second failure I plugged the two valves with plumbing end caps. Problem solved. I will re-install the hose and valves when I am ready to sell the car in the future.

    It's warm enough here in CA where any way.

    Kai
     
  21. vvassallo

    vvassallo F1 Veteran

    Aug 4, 2006
    8,213
    Palos Verdes
    Full Name:
    Vince V
    I like that noise. In fact, I want to try to keep it on all the time. :)
     
  22. FandLcars

    FandLcars F1 Rookie

    Aug 6, 2006
    3,043
    Tempe, Az
    Full Name:
    Rick Schumm
    Mine isn't a nice sound, it's more of a rattling metallic sound. Seems to definitely be the check valves.
     

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