Engine/Transmission (1998.5 - 2002) 2001 Cummins Ram fuel tank connections & vent

[Gordon Maney]

I am installing my new Raptor pump kit, big line kit, VP44, and fuel presssure gauge. As I maneuver under the bed to examine the fuel tank connections in preparation to make a new connection for the Raptor I noticed a small tube connection stub capped with a rubber cap held in place with a small clamp.

I believe I recall some years ago seeing a TSB that talked about some trucks having vents that were not open, requiring removal of a cap or plug. This truck has 129,000 miles on it, so present circumstances have not prevented it from running. I do wonder why this connection is capped. The bed is in place, so I cannot see really well, but seek opinions on this situation.

The other question; if there is an open vent there, what prevents dirt from entering? Is this supposed to vent via a hose running far forward?

Please offer your thoughts, thank you.

 

[Mishkaya]

I am installing my new Raptor pump kit, big line kit, VP44, and fuel presssure gauge. As I maneuver under the bed to examine the fuel tank connections in preparation to make a new connection for the Raptor I noticed a small tube connection stub capped with a rubber cap held in place with a small clamp.



I believe I recall some years ago seeing a TSB that talked about some trucks having vents that were not open, requiring removal of a cap or plug. This truck has 129,000 miles on it, so present circumstances have not prevented it from running. I do wonder why this connection is capped. The bed is in place, so I cannot see really well, but seek opinions on this situation.



The other question; if there is an open vent there, what prevents dirt from entering? Is this supposed to vent via a hose running far forward?



Please offer your thoughts, thank you.

Where is this connection stub located exactly? It's most likely capped because indeed the fuel tanks for diesel and gas are slightly different and if a gasoline tank was used, the location for the check valve needs to be capped off to avoid contamination of the fuel tank. Not sure my explanation is clear though. There should be a vent hose installed; it goes up along the filler neck; cannot recall where it connects on the tank though and as it is snowing heavy I don't want to go out and look...

 

[Gordon Maney]

Yes, there is a vent line running up the filler neck. If the cap is not vented then that would only have value during a fill.

A new question. Which of the two lines to the tank is the supply and which is the return? It appears to me the somewhat larger line is the supply, and the smaller one is the return. The larger one is the outermost line on the module. I am not finding any manual illustration identifying these, and web searches are not getting me an answer. I suspect that has been covered in these forums before.

 

[Mishkaya]

Yes, there is a vent line running up the filler neck. If the cap is not vented then that would only have value during a fill.



A new question. Which of the two lines to the tank is the supply and which is the return? It appears to me the somewhat larger line is the supply, and the smaller one is the return. The larger one is the outermost line on the module. I am not finding any manual illustration identifying these, and web searches are not getting me an answer. I suspect that has been covered in these forums before.

Here is an old Airdog install guide. It shows the info you need. The fuel supply line is the one towards the rear of the truck as the lines come out. Diagrams are in the PDF

http://www.dieselbookmarks.com/bombers/air dog install 24V cummins.pdf

 

[BarryG]

Gordon:

The capped line is an auxillary supply port, if you take your cannister out to do this work you will see that it is connected to a hose that runs down along the side of the cannister inside the tank.



The 3/8 line is the supply line, the 5/16 line is the return line.



The rollover valve is also the vent, there are no other vents in the tank except as you noted the fill vent

 

[Gordon Maney]

Gordon:
The capped line is an auxillary supply port, if you take your cannister out to do this work you will see that it is connected to a hose that runs down along the side of the cannister inside the tank.

The 3/8 line is the supply line, the 5/16 line is the return line.

The rollover valve is also the vent, there are no other vents in the tank except as you noted the fill vent

Thank you. It is virtually impossible to trace the lines all the way from the front.