Join Date: Apr 2010
Ferrari Life Posts: 2,199
Mark you may also be experiencing some fuel vaporisation in your fuel rails due to heat soak. This would cause the symptoms you're describing.
Returnless fuel systems have no mechanism to keep cool fuel in the rails as return type systems do, so when the car is shut off, the engine sits there and heat soaks for awhile, and if the fuel pressure drops in the rails, voila you have vaporisation.
What you might want to do is ask your technician to put a pressure gauge on your fuel rails and when you turn the car off, see if the pressure holds or it bleeds down. You should have check valves in your system back near the fuel pumps which should keep the fuel pressure high in the rails even with the engine shutoff, but if these check valves are leaking, it could cause the pressure to bleed off, and the fuel is sure to vaporise.
'99 550, Rosso Corsa / Nero, S/N:114654, Assy: 31836, Engine: 52084
High mileage, low compression, and missing on a few cylinders.....just like my cars.
Maranello Skunkworks Team Member