Ford Focus ST Forum banner

High Pressure Fuel Pump Pressure and Leak

6699 Views 1 Reply 2 Participants Last post by  tpiechow

My high pressure fuel pump has sprung an oil leak twice now. The o-ring was replaced by a tuning shop the first time and is about to be replaced by the dealer... I took an accessport log of a third gear pull the other day. Over the pull I saw my fuel rail pressure increase from 1500 to 3000PSI (graph attached). I've read that this may not be a good sign, so I'm wondering if this is somehow related to the recurring oil leak?

Any thoughts?

Text Blue Line Plot Font
See less See more
1 - 2 of 2 Posts
The high pressure pump sits on the valve cover and is driven by one of the camshaft lobes on the back of the head. So the only oil involved is getting splashed up from the camshaft, oil pressure is not used to create fuel pressure. So it's either the seal or there is an issue with the sealing surface on the pump or the cover.

In regards to fuel pressure, it is hard to tell if a 1500 PSI jump is a bad thing or not. The PCM controls a FVR (fuel volume regulator) that is internal to the high pressure fuel pump. It can vary the pressure from 75ish PSI to 3000ish PSI. So to determine if the 3000 PSI is a bad thing, you would have to look at FRP (fuel rail pressure) actual and desired. And just like it sounds, desired is what the PCM is commanding and actual is what is being measured at the fuel rail.
1 - 2 of 2 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.