rockhead11

Has anybody watched their fuel rail pressure when you stopping? Drive 55 or so and let off of the gas a little early coming up to a stop sign. If I watch my fuel rail psi, it will keep rising until the torque converter lets go. (that might be trivial). Is that supposed to do that? If not, could that be the reason that some people are getting fuel in the oil?

rockhead11

Nothing

itguy08

Been a whie since I watched it that closely but I know it tracks closely with RPM and load. Hit the gas and it will shoot up and it also stays up on high RPM. Since there is no return on the high pressure side, it would make sense for it to stay high until the system can bleed enough pressure through the injectors to get it down. But, the injectors should be capable of holding the fuel back without leaks no matter what the pressure.

There is a good writeup on the fuel system here:
http://www.underhoodservice.com/Arti...s_a_boost.aspx

rockhead11

Thank you for looking. The psi will drop off when you let off the gas and then as you are slowing down without hitting the brakes the psi creeps back up.

itguy08

No problem. It is fun to watch this all work and I'll have to pop in my adapter next time I go for a drive and see what it does.

It might make sense as I think Ford uses the Aggressive Fuel Shutoff on deceleration in the trucks. Basically when you let off the gas they shut off the fuel to the engine. I think it comes on when downshifting and you get below a certain speed. Since the pump is always turning and there is no return it may explain why pressure creeps up.