I have read posts on here before about a rubber cap on the top of the fuel tank sending unit that is not supposed to be there. I did a search but could not find anything. There are two spots that look like they could be for the vaccum relief. There was on black rubber cap that was pointing straight up. It was about a 5/16 rubber cap with a metal band clamp. I figured that was the one so I took it off. There is also a black 90 degree fitting that is about an 1/8 inch and it has a barb on it. It did not have a rubber cap on it. I was wondering if somebody had already taken the rubber cap off or if I did take the right one off. Thanks for any help.

 

I believe the 90 degree barb is the pressure relief/rollover valve and the barb sticking straight up with the rubber cap is the auxiliary supply port.

 

http://dodgeram.org/tech/dsl/ISB/low_power.htm