Fuel pressure regulator
ehhhh... not necessarily. Maybe of course, but... there's always the possibility that your fuel pressure is low, and removing the line boosts the pressure higher to compensate ??
Might just be worth your while to test your fuel pressure before you spend the money on the regulator if it's ok. If you follow my thinking.
It's your money of course, and you could be bang on with the fpr, but if it's actually pressure levels and not the fpr, you could save your money to put towards the filter or pump that low pressure would indicate.
A fuel pressure gauge is the only way to know for sure (but you probably already knew that).
Might just be worth your while to test your fuel pressure before you spend the money on the regulator if it's ok. If you follow my thinking.
It's your money of course, and you could be bang on with the fpr, but if it's actually pressure levels and not the fpr, you could save your money to put towards the filter or pump that low pressure would indicate.
A fuel pressure gauge is the only way to know for sure (but you probably already knew that).
Senior Member
Joined: Mar 2021
Posts: 4,804
Likes: 2,398
The fuel system in a 3.3 is in two parts.
A low-pressure system feeding a Cam driven high pressure pump through a check valve arrangement.
Forscan should be able to see it at Key on before cranking and after engine is running. This gets to see both system pressures.
Expect to see pressures as high as 2000 to 3000 psi under running conditions
These high-pressure levels must overcome cylinder pressure or injectors could not open to provide proper atomization.
I can see this in a dual injection engine using a Scanner looking at that PID where both Low and High register from Ignition on to running pressures.
I would be looking at the Long Term Fuel Tables both banks for shifts positive more than 5% on a continuous basis.
Maybe there is a need to change plugs, Ox Sensors etc.
Fuel may be a factor.
Hard to put a cause on it without some suspected proof.
Winter Gas formulation change is coming soon that will affect mileage in many localities.
Good luck.
After I sent this response it looks like it went to a wrong thread.
If so just ignor it.
A low-pressure system feeding a Cam driven high pressure pump through a check valve arrangement.
Forscan should be able to see it at Key on before cranking and after engine is running. This gets to see both system pressures.
Expect to see pressures as high as 2000 to 3000 psi under running conditions
These high-pressure levels must overcome cylinder pressure or injectors could not open to provide proper atomization.
I can see this in a dual injection engine using a Scanner looking at that PID where both Low and High register from Ignition on to running pressures.
I would be looking at the Long Term Fuel Tables both banks for shifts positive more than 5% on a continuous basis.
Maybe there is a need to change plugs, Ox Sensors etc.
Fuel may be a factor.
Hard to put a cause on it without some suspected proof.
Winter Gas formulation change is coming soon that will affect mileage in many localities.
Good luck.
After I sent this response it looks like it went to a wrong thread.
If so just ignor it.
Last edited by Bluegrass; Sep 24, 2025 at 10:48 PM.
