News

Reason for unable to rev beyond...

Discussion in '308/328' started by Crowndog, Aug 1, 2020.

  1. Crowndog

    Crowndog F1 Veteran
    Rossa Subscribed

    Jul 16, 2011
    6,997
    Fairfield,Pa
    Full Name:
    Robert
    #1 Crowndog, Aug 1, 2020
    Last edited: Aug 1, 2020
    4800 rpm. Any ideas? My first thoughts:

    Broken throttle position switch (no wot signal) I only hear one click turning the throttle through full range. I think it should have 2

    Fuel pressure regulator not working correctly

    Vacuum leak

    What do you think? Also no high speed idle at cold start.

    Any suggestions are welcome. This is a 4 valve injected 308
     
  2. Smiles

    Smiles Moderator
    Moderator Owner

    Nov 20, 2003
    13,992
    Pittsburgh, PA
    Full Name:
    Matt F
    But you do have full power?

    Matt
     
  3. Crowndog

    Crowndog F1 Veteran
    Rossa Subscribed

    Jul 16, 2011
    6,997
    Fairfield,Pa
    Full Name:
    Robert
    No. It only revs to 4800rpm but does it well up to that point.
     
  4. Smiles

    Smiles Moderator
    Moderator Owner

    Nov 20, 2003
    13,992
    Pittsburgh, PA
    Full Name:
    Matt F
    Then I don't know. Interesting.

    Matt
     
  5. Crowndog

    Crowndog F1 Veteran
    Rossa Subscribed

    Jul 16, 2011
    6,997
    Fairfield,Pa
    Full Name:
    Robert
    I will add that almost all vacuum lines are original braided covered.
     
  6. kiwiokie

    kiwiokie Formula Junior

    Aug 19, 2013
    885
    Tulsa, OK
    Cat or no cat?


    Sent from my iPhone using FerrariChat
     
  7. Crowndog

    Crowndog F1 Veteran
    Rossa Subscribed

    Jul 16, 2011
    6,997
    Fairfield,Pa
    Full Name:
    Robert
    Cat
     
  8. mike996

    mike996 F1 Veteran

    Jun 14, 2008
    5,464
    TX//Mexico/UK
    Full Name:
    Mike 996
    Did this behavior begin abruptly or has max RPM been gradually decreasing? Is the max RPM the same regardless of engine load, same 4800 RPM max whether accelerating in neutral or on the road in gear?
     
  9. kiwiokie

    kiwiokie Formula Junior

    Aug 19, 2013
    885
    Tulsa, OK
    Plugged cat?


    Sent from my iPhone using FerrariChat
     
    Steve Magnusson likes this.
  10. Steve Magnusson

    Steve Magnusson F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    19,154
    Texas
    Full Name:
    Steve Magnusson
    No, the idle switch has an audible click, but the WOT switch is a (soundless) pair of contacts (closed by a cam) that allows over-travel:

    Image Unavailable, Please Login

    Have you put a timing light on it to confirm/deny you aren't losing a bank of ignition?

    Also, is the warm idle unchanged (i.e., it's still the same as it was when it would rev over 4800 RPM)?
     
    Saabguy likes this.
  11. Crowndog

    Crowndog F1 Veteran
    Rossa Subscribed

    Jul 16, 2011
    6,997
    Fairfield,Pa
    Full Name:
    Robert
    Mike it was gradually
     
  12. Crowndog

    Crowndog F1 Veteran
    Rossa Subscribed

    Jul 16, 2011
    6,997
    Fairfield,Pa
    Full Name:
    Robert
    Thank you for the clarification.
    No timing light test....yet
    Yes
     
  13. Crowndog

    Crowndog F1 Veteran
    Rossa Subscribed

    Jul 16, 2011
    6,997
    Fairfield,Pa
    Full Name:
    Robert
    The engine in question is in a Mondial 3.2
     
  14. mike996

    mike996 F1 Veteran

    Jun 14, 2008
    5,464
    TX//Mexico/UK
    Full Name:
    Mike 996
    If it occurred gradually, it could very well be muffler or cat breaking down internally/clogging as was suggested earlier. I've worked on cars with mufflers or cats so badly clogged that the engine could only idle - no power available above that.
     
  15. AUDIO RESEARCH

    AUDIO RESEARCH Formula Junior

    Feb 11, 2009
    293
    PHILIPPINES
    Full Name:
    LUIGI RAYMUND LIRA
    What happens when the engine reaches 4,800 RPM , is there some sort of a misfire , or lost of power ? This happened to my 3.2 Mondial when the new Bosch Fuel Pump I installed was from a Mercedes 280SE . Idling and power was perfect but when it reach 5000 RPM misfiring and lost of power . When I installed the proper Bosch fuel pump for the Mondial problem solved .
     
  16. miketuason

    miketuason F1 World Champ
    Silver Subscribed Owner

    Feb 24, 2006
    13,890
    Cerritos, CA.
    Full Name:
    Mike
  17. mike32

    mike32 F1 Rookie

    May 13, 2016
    2,786
    Uk
    Is this 4800 max in any gear or just in top ? Fuel filter will limit revs in top if getting dirty
     

Share This Page