365 GTB/4 engine runs rough after being parked 1 hour with warm engine

Discussion in 'Vintage (thru 365 GTC4)' started by thecarnut, Jun 28, 2020.

  1. turbo-joe

    turbo-joe F1 Veteran

    Apr 6, 2008
    southwest germany
    Full Name:
    romano schwabel
    if too lean or too rich - this all does not matter that after 15 minutes the engine is runing fine

    I not know daytona much. so 2 fuel pumps? like in the 250 GT/E, so 1 mechanical fuel pump at the engine and 1 electric fuel pump in the rear near the fuel tank? so there the electric pump will deliver fuel from the tank to the carbs and then stopped at the mechanical fuel pump. and when once engine is running the electric pump can be switched off and the mechanical fuel pump delivers fuel from the tank to the carbs and back to the electric fuel pump where it stops. the fuel pressure is regulated by the spring in the mechanical fuel pump.
    or is it like in a BB with 2 parallel electric fuel pumps? so 1 fuel line from the tank is splitted into 2 lines , then the 2 pumps, and then again together those 2 lines into 1 line and then to the carbs?
    on my BB I once had an equal problem and I then put each pump to each cylinder bank and after the carks again together into 1 line back to the fuel tank. since then never had problem. on a daytone not possible because of the carbs.

    you also have this problem when not driving. so try to let the engine run and when there is the problem you may test with an infrared thermometer the exhaust manifolds to see a temperature difference
  2. TTR

    TTR Formula 3
    Silver Subscribed

    Mar 29, 2007
    Riverside, CA
    Full Name:
    Romano, 365 GTB/4 is equipped with 2 parallel electric pumps, mounted to chassis in front of LH rear suspension with single hose to fuel rail, no mechanical.
    turbo-joe likes this.

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