Drill a hole into Fuel Filler Neck?

67,

Well unfortunately, the FiTech needs a quasi return line although they call it a vent. In some conditions the FCC can & will spit some fuel out along with it's need to breath so it's 340 lph pump does not lock up or otherwise stop. So there will be a bit of liquid spewed into the vent (return) line. I want this small bit of fuel to either vaporize (hopefully) and go into the tank, or push the liquid into the tank as the volume increases or maybe pull back or vaporize into the FCC. For me to add a vent (return) to the neck will require the possible fuel to "climb" up to a suitable place to add a inlet to the filler neck. So that is maybe another 6" maybe over the top of the tank to find a place on the tube inside the trunk. By running it into a tank sending unit instead will lessen the upward flow. There is already an elevation of several inches from where the fuel/vent lines come up from the frame rail to get level with the top of the tank. I hope that clears up my dilemma. It's a returnless system but still needs some relief. To go to true return setup I would need to abandon the FCC and go with a tank hp pump or an inline hp pump direct to the FiTech throttle body and then a proper returnline added from that to the tank.

FYI,

Marion

Also, I do have a vented cap on the car for those inquiring minds.

mario03srt said:

Also, I do have a vented cap on the car for those inquiring minds.

Click to expand...

Not all vented caps vent IN, some just vent out so be careful with that.
If this were me, as someone who has installed and ran 100 fitechs....

I'm assuming you don't have a vent running to atmosphere on the fuel sending unit in the tank? If you do, then thats your atmosphere vent, so you just need the FCC Vent/overflow (which you described perfectly) somewhere ELSE back into the tank...like the BOTTOM of the filler neck, which you should be able to carefully remove w/o hurting anything at all.

If you don't have a vent to atmosphere on the fuel pickup, then remove the filler neck, put the FCC vent on the lowest spot you can on the neck, under the trunk, and then add another barb to the top near the filler. Run that one back out of the trunk, and into a framerail or something. Bottom barb/line will be adequate for the fcc fumes or any "burp" fuel. The top will vent to atmosphere and safely expel fumes while allowing venting, back out of the tank.

done

It's so easy to remove, why would you consider otherwise?

Besides, the correct way to install a vent nipple is to braze or solder it in. Might not wanna do that with it still installed.

Johnny,

This fuel sending unit has 1 port that went to the Char Cannister. It has a pinhole opening which I'm assuming is like on the other end of the factory vent tube which is a check or pressure release inline valve. I'll look at the FSM to see. I cut off the 1/4" vent tube back an inch the one engine bay side so it will flow. I would have to drop the tank to either 1. trim the port on the sending unit to clear the restriction. 2. Get a new sending unit that is plumbed properly for a vent w/o restriction. From there add a short hose to connect the 1/4 line to the new sending unit. #2 being the best option. I could incur collateral issues from gaskets and rubber grommets etc. My current fuel system for a car that 45 years old works great (has been maintiained) as is and cracking the seal so to speak on it can be a slippery slope.

My 73 Dart only has 2 inches of open filler tube length between the fuel tank and the trunk floor, there is a rectangular rubber boot that screws onto my trunk floor that provides closure of the trunk area from the filler neck passing through. This is the top surface that the filler tube passes through, also a barb would have to slide through this and that won't work, there is just no room for hoses and a barb in general. The barb would have to be above that and in the trunk area on the opposite side. Soooooo, That why I was asking about everyone's half serious risk assessment of about drilling a hole. The McGyver in me says to wad up a wet cloth stuff it down the neck with a lanyard, blow in some fresh air, drill easily with some WD40 and some grease on/in the bit to hold debris. Pull out the rag with any debris! But I won't bet my life that this is a good process ! The more I think about it the filler neck barb probably should have a turndown to keep fuel from going into it when filling up! Not a perfect solution but easy and cheap. But wayyy up hill. Just trying to reduce effort and work but not take any unnecessary risks and get this right. Trying not to be pissed about my returnless system.

Thanks,

Marion

I have the same dart as you my man, i know how the grommet works. lol. on the lower one BELOW the grommet, i see no reason you can't run a TAP through the hole you drill to thread in a barb. AFTER you slide it back through the trunk grommet. I know its thin walled but i have had guys seal them with teflon paste, or even epoxy sealer. You very completely understand how the FCC will only burb fuel on occasion, if at all. We're not talking a pressure fed line here. Also with the fuel modulation settings in the handheld, you can turn the pump down and it will burp even less.

If you weren't on the other side of the state i'd tell you ro bring it to me!

Well, when I did mine, I used grease on the drill bit, ran a vacuum while I drilled, and placed my brass barb inside the trunk, just above the trunk surface. I used epoxy seal all, and have had no leaks, smells or issues since. My filler neck has an inner sleeve of some sort, so I used the drill just enough to cut the outer metal. No issues with my FCC either since.

Ken

All,

Well I got er' done. The filler neck came out with 4 screws.. Had to tug on the tube quite a bit to get it out of the collar on the tank. I cleaned up the tube and added a 1/8 npt hole to accept a 1/4 brass barb. I scribed a position on the tube while still in place on the car. Just above the collar and below the rubber access boot and removed and drilled. Threaded it in and used JB Weld to permanently hold it there. I decided to reuse the ol' gasket and collar/grommet. Ran the fuel hose around the shock and tank to the stock vent hard line near the sending unit. I left the stock vent nipple on the sending unit open and will add a 90 deg elbow to keep fine dirt out although it has a check valve that only opens when needed. After letting the JB cure, fired her up and no issues.

Thanks to all for the input! Got off my *** and just did it in a few hours total in my drive!

Thanks,
Marion