Which is the high pressure (supply) line at the fuel rail?

1993 LINCOLN TOWN CAR
250,000 MILES
Avatar
LINCOLNMAN
  • MEMBER
  • 1 POST
Can't follow the fuel lines up to the rail all the way, so it is almost impossible to tell which line from the rear goes to which side.
Apr 1, 2012 at 10:08 PM
Advertisement
Avatar
KASEKENNY
  • ✓ASE Certified Mechanic
  • 18,907 POSTS
  • ASE Certified Mechanic
The return line is the one that is leaving the pressure regulator so the other line coming into the fuel rail is the supply line.

The regulator is on the return side of the system, and it controls the pressure by allowing the proper amount of fuel back to the tank, so they are after the injectors.

So, this means then line that is connected to the regulator is the return line.

If you are still not sure, then just connect them to a rubber line and run them to a bucket and the one that squirts fuel is the pressure line.

Please let us know what other questions you have.

Thanks
Images (Click to enlarge)
Professional Diagram for 2CarPros Members
Click here to log in and view diagram.
Professional Diagram for 2CarPros Members
Click here to log in and view diagram.
Professional Diagram for 2CarPros Members
Click here to log in and view diagram.
Professional Diagram for 2CarPros Members
Click here to log in and view diagram.
Dec 11, 2021 at 6:23 PM
Join 2CarPros for free, one of the most advanced car repair communities on the internet. From first-time drivers to seasoned mechanics, everyone is welcome to reply, share details, and get better answers. You can add a temporary image or video first; uploads are limited to 20 MB.
Ask a Free Question
Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.