Ferrari 355 5.2 1997 UK Car Engine Reving Problem | FerrariChat
Buy

Ferrari 355 5.2 1997 UK Car Engine Reving Problem

Discussion in '348/355' started by 355OXO, Aug 21, 2023.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, Skimlinks, and others.

  1. 355OXO

    355OXO Karting

    Apr 16, 2006
    204
    UK
    Full Name:
    Simon
    #1 355OXO, Aug 21, 2023
    I was hoping that one of you experts would be able to help me with a recent problem.

    I have had a problem where the tickeover RPM has been 200 rpm less than normal.

    I took the car out for a fairly vigourous drive of around 30 miles, as I was returning home at the end of this drive I had a problem with the car revving excessively without me depressing the accelerator pedal. The only way to stop this was to turn off the ignition.

    I don't believe this is a sticking throttle cable or a broken return spring.

    Any ideas or suggestions as to what could cause this to happen.
     
  2. Targatime

    Targatime Formula 3

    Feb 22, 2014
    1,449
    Los Angeles
    #2 Targatime, Aug 21, 2023
    Why don't you think it's a sticking throttle?
     
  3. 355OXO

    355OXO Karting

    Apr 16, 2006
    204
    UK
    Full Name:
    Simon
    #3 355OXO, Aug 21, 2023
    Because the revs increase to maxwithout pushing the accelerator pedal down.
     
  4. Ferrarium

    Ferrarium F1 Veteran
    Sponsor Rossa Subscribed

    Jul 28, 2018
    5,728
    Central NJ
    Full Name:
    Eric
    #4 Ferrarium, Aug 21, 2023
    And the throttle bodies are not opening? To rev it needs air. They are mechanical you can physically see linkage if they are opening some how.
     
  5. Targatime

    Targatime Formula 3

    Feb 22, 2014
    1,449
    Los Angeles
    #5 Targatime, Aug 21, 2023
    This can be consistent with a sticking throttle cable or bellcrank. It's so easy to check if the throttles are sticking open that you should rule this out. Make sure to test with the engine both cold and hot.
     
    355OXO likes this.
  6. 355OXO

    355OXO Karting

    Apr 16, 2006
    204
    UK
    Full Name:
    Simon
    #6 355OXO, Aug 21, 2023
    I will double check and confirm.
     
  7. Qavion

    Qavion F1 World Champ
    Silver Subscribed

    Feb 20, 2015
    14,269
    Sydney
    Full Name:
    Ian Riddell
    #7 Qavion, Aug 21, 2023
    Too high and too low?

    Did you try to address the low idle problem (before the Italian tune-up)? Sounds like you have two issues now.

    For the low rev problem:
    Do the revs rise when you turn on the AC?
    Did you try cleaning the Idle Air Controller internals and connector?
     
  8. yelcab

    yelcab F1 World Champ
    Consultant

    Nov 29, 2001
    13,549
    San Carlos, CA
    Full Name:
    Mitchell Le
    #8 yelcab, Aug 21, 2023
    The first question I would ask is "Did you or anyone else just work on this car, and if so, what was done?"
     
    Qavion likes this.
  9. 355OXO

    355OXO Karting

    Apr 16, 2006
    204
    UK
    Full Name:
    Simon
    #9 355OXO, Aug 22, 2023
    Hi, The car had a full top end rebuild, heads skimed, velocity stacks cleaned, new valves and guides. This was all undertaken by a Maranello trained 355 mechanic and refitted by him.
    Obviously it had a major service at the same time replacing all belts and related parts.
    It's possible that I need to rebalance the velocity stacks as these were cleaned when removed. I think this will address the low idle problem.

    I have driven the car 200 miles since the rebuild and then I experienced the increasing revving problem, this was after a fairly vigourous drive.
     
  10. 355OXO

    355OXO Karting

    Apr 16, 2006
    204
    UK
    Full Name:
    Simon
    #10 355OXO, Aug 22, 2023
    I have not tried cleaning the idle air controller.
     
  11. Ferrarium

    Ferrarium F1 Veteran
    Sponsor Rossa Subscribed

    Jul 28, 2018
    5,728
    Central NJ
    Full Name:
    Eric
    #11 Ferrarium, Aug 22, 2023
    355OXO likes this.
  12. Qavion

    Qavion F1 World Champ
    Silver Subscribed

    Feb 20, 2015
    14,269
    Sydney
    Full Name:
    Ian Riddell
    #12 Qavion, Aug 22, 2023
    The OP said he had a low idle problem originally, hence my comment about him possibly having two issues. Of course, this was before we all knew he had the stack redone.

    Now the smoking gun is somewhat bigger…
     
    355OXO likes this.
  13. yelcab

    yelcab F1 World Champ
    Consultant

    Nov 29, 2001
    13,549
    San Carlos, CA
    Full Name:
    Mitchell Le
    #13 yelcab, Aug 22, 2023
    Well, the smoking gun is ... a smoking cannon.
     
    355OXO and Qavion like this.
  14. 355OXO

    355OXO Karting

    Apr 16, 2006
    204
    UK
    Full Name:
    Simon
    #14 355OXO, Aug 26, 2023
    I think i have fixed the problem, i disconnnected the throttle cable and the revs did not increase without me manually turning the butterfly linkage, cable is not sticking or dragging, cleaned throttle floor pedal and lubed bush and this seems to have resolved issue, need to road test to confirm but it is raining so will have to wait for a sunny day.
     
    Qavion likes this.
  15. yelcab

    yelcab F1 World Champ
    Consultant

    Nov 29, 2001
    13,549
    San Carlos, CA
    Full Name:
    Mitchell Le
    #15 yelcab, Aug 26, 2023
    It has been my experience that the throttle cable and its set up is very prone to interference and stickiness which causes idle speed issue. Everytime, for me.
     
    355OXO likes this.
  16. Targatime

    Targatime Formula 3

    Feb 22, 2014
    1,449
    Los Angeles
    #16 Targatime, Aug 26, 2023
    Clean and lubricate the needle bearing in the bellcrank
     
    355OXO likes this.
  17. 355OXO

    355OXO Karting

    Apr 16, 2006
    204
    UK
    Full Name:
    Simon
    #17 355OXO, Aug 28, 2023
    Thanks for all the input and help, I love my 355 but anything you do on a 355 is always a pain in the backside to work on. Nothing is ever simple.
    Much appreciated for all your help and support.
     

Share This Page