5.8FSI fuel reservoir modification

[ChrisinPHX]

A user (Larson220) in a closed thread wrote this regarding the fuel reservoir on these 5.8FSi Ford motors.

• "This engine type has a fuel reservoir at the back of the engine. THIS FUEL RESERVOIR CAUSES MANY ISSUES.
  It is basically a small fuel tank that stores a small amount of fuel for the high pressure pump. There is a small float inside that is connected to a valve.The purpose of the valve is to vent excess fuel vapors to the intake manifold.
  if you look there is a vent hose that goes to the bottom of the intake air tubes.
  What happened to my engine was that the pumps would run and overfill the small tank, thereby flooding the engine.
  this would cause a no start condition.
  THE SOLUTION- FIX: Disconnect the vent line from the intake plenum, then connect a long fuel hose to the vent connection at the fuel reservoir and connect it to your boats gas tank if possible. VERY IMPORTANT DO NOT LEAVE THE HOSE DISCONNECTED- FIRE HAZARD. You have to put a plug cap on the intake plenum to prevent a vacuum leak. This fix will eliminate many of the fuel pump reservoir issues that plague this system."
• I would like to do the modification to the vent line from the fuel reservoir. I don't have an extra port to tap this into the tank. Can I just splice this vent line into the existing vent line the tank uses? Anyone see any issues with doing that?
• Thanks, Chris

 

[Larson220]

Chris, you can splice it into your existing vent line, however make the splice as close to the tank connection as possible. Use approved gas line brass tee and make sure that you use good gas line clamps to secure the hoses. Do not buy cheap auto part junk gas hose clamps or hoses, make sure that you buy Coast guard approved hose and clamps from a marine store. You also have to make sure that you cap the old vent hose connection at the manifold, otherwise you will have a nasty vacum leak. Good luck.

 

[ChrisinPHX]

Perfect! Thanks for those tips!!

 

[ChrisinPHX]

Turns out my fuel vent line is 5/8 ID. That's huge compared to the line coming off of the reservoir that I believe is around 1/4 ID. I can't seem to locate a tee for a 5/8 ID that has one leg of the tee 1/4. So in that case I need the 5/8 tee, another piece of 5/8 ID hose and then a reducer from 5/8 to 1/4" and 5 hose clamps. That's honestly way more splices than I want to do for something I was considering doing as a preventative thing. Would be much easier is someone made brass tees of various sizes with different size legs.

 

[Larson220]

I agree, but perhaps your fuel tank has an extra fuel port that is plugged. My boat has a large hatch that
gave me access to the top of the tank. I was able to install a fitting to run the vent/drain hose.
If you are not having any issues with the engine, then just leave it alone.