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Randall C
Randall C, ASE MasterTechnician
Category: Ford
Satisfied Customers: 12803
Experience:  35 years ASE Master Tech, Diagnostic , Electrical Specialist
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Have a tube coming from the top of my fuel rail drivers

Customer Question

have a tube coming from the top of my fuel rail drivers side.( it is on the front by the first injector no 2 cylinder)
on one side is an electrical conn the other side is a (evap) hose small 3/8 od need to know where it connects to. just noticed it and heard a hissing noise under the hood
ford f150 5.4l 3v engine
Submitted: 1 year ago via ChiltonDIY.
Category: Ford
Expert:  Randall C replied 1 year ago.

Hello, I think I know the valve, can you send the wire colors to it to be sure?

Customer: replied 1 year ago.
cant see the wire colors right now took a picture but I would have to text it to you.
it is attached to the fuel rail the electrical conn is grey and goes to the fuel injectors the other side is where the black 3/8 tube is coming out but were it is supposed to connect to I cant tell. could be a vacuum line?
Expert:  Randall C replied 1 year ago.

It is the fule pressure sensor and fuel temp sensor combined, Yes, 100% it is a vacuum line, It runs down the fule rail on drivers side, makes a band around back of intake and then hooks to a nipple in the intake, The problem? I can find any picture to send to you of this vacuuum port, It is real close to where the vacuum brake booster hose, the 1/2" diameter hose from booster to back of intake. I wish I had a pic to send. Its a tight area but should be able to follow the brake booster hose, hwre it hooks to back of intake. Run engine and feel around that area or listen for the leak in that area, I know it helps if you remove the air inatke from top of the throttle body to make room to locate the fitting, This is why you hear a vacuum leak but,, it is around back of intake, Hard to see but it is shown as #8 in this link and lower left diagram, That is the vacuum hose

Customer: replied 1 year ago.
will check after work tomorrow. Thanks
Expert:  Randall C replied 1 year ago.

I will be on off, wish I could send more but 100% it is a vacuum line that broke or came off at rear of intake