So I started on the journey of a LS swap 1 year ago, and honestly was over my head. Ended up hiring some help, but the car is essentially complete.

My main issue after the swap is now I can't fill the gas tank without the gas pump shutting off every 2 seconds. I also can smell gasoline in the air outside the car which I know is not good. Any suggestions? Thanks.

 

Was the gas tank messed with at all during the process? Any work done around the rear of the car?

 

sounds to me maybe you have moved the charcoal trap and capped the fuel tank vent line

probs need to re-establish the trap, and route it to aircleaner or PCV

 

I agree with that.
Check your vent line at the top of the tank.
Also look at the car's FSM and get the Vacuum routing for the fuel system as it will show you what you need to look at.

 

My gas vent was clogged forever before and never gave any gas filling issues. It takes a whole tank non stop.
For many years I thought it was normal for my tank to release air when I removed the gas cap after. I had the tank vent hose attached to the original metal line that goes to the engine bay alongside the fuel feed and return lines. The metal line had gotten clogged somehow. I disconnected vent hose from the hard line near the tank. My tank doesn't have the air rushing sound when removing gas cap anymore. Either way... I never had gas fill up issues.

 

I just had the charcoal canister line set up welded over on my gas tank, think im going to have an issue?
I figured the overflow tube would perform the same task

 

I have this issue at some gas stations, but the station I go to normally I do not have this issue.

When you ump gas, tilt the handle of the nozzle upward when you are pumping gas.

 

there needs to be a vent in the tank, as it needs to be able to bring in air to replace the fuel

 

most pumps arent those ones you had to push in real tight to get to work, im thinking the overflow tube and the fact there is space around the gas pump spout should be good enough


Guess I will see and worry about it when I have to worry about it

 

I purchased a car like this once. The rubber filler neck was twisted and wouldn't let the gas flow through fast enough. This made the pump think it was full and shut off. If you look down into the filler neck, does it look like it sort of spirals?

 

Thanks for all the good suggestions.

The fuel pump was modified, replaced to larger fuel line to tank, and i believe the charcoal trap was moved. Not sure about the vent line. Hope to try these suggestions soon and provide an update.

 

something i have seen first hand, several times,, and then years later , even in rx8 bulletins


wasps nesting in the vent lines

they seem to be attracted to the faint hydrocarbon odour

just putting it out there.. more common than you think

 

I had a supremely clogged vent line. So clogged 100psi and a rubber tipped nozzle could not get it Unclogged. I had to pull out rubber hose where it attached to the hard line by the gas tank it was clogged for 5 years and for 5 years i had no fill up issues. Everytine i opened the gas cap you woukd hear air rushing. For five years...either way it never gave me fill up issues.... 1 more time?

I agree with gas not flowing into tank smoothly. Pump have sensors and when fuel is sensed at pump nozzle it will do what you are describing. It will click to avoid an overfill and a fuel spill. So you have to keep throttling the handle..

 

Just lift the handle portion of the nozzle up!

This issue will almost always occur at a gas station that has a VOC recovery system with the accordion looking rubber **** over the nozzle. That stupid thing prevents full insertion of the actual pump nozzle and so the end of the pump nozzle sits right up against the gas tank filler neck. Gas dispensing nozzles have air holes in the where vaccuum is applied and if the vacuum gets high enough, it stops the pump (thinking your tank is full). Since that goofy thing orients the nozzle wrong the end of the nozzle gets pointed at the side wall of the filler neck so gas spills back over the holes and incorrectly tells the gas pump is full.

I always have the same issue at Tom Thumb with the VOC recovery system. What I do is Shove that bitch in there like an angry rapist and tilt the handle up. Pain in the *** I know, but hey I am saving a dollar per gallon.

$1.88 - $1.00=

 

I've seen a fuel pump suck so much pressure on a 1st gen tank (turbo 13B) where the vent line was welded up that it actually accordianed the tank. Which would cause fuel pressure issues after hard drives or even long drives. Was a real pain to troubleshoot as no one looked at the tank. It wasn't until the tank was opened right after driving that there was a loud "BANG!" and it sprang almost back into shape.

So yeah, that vent line is important. Though FCs use pressure equalizing fuel caps which allow air in, so that might be less of an issue.

 

I'm going to get a new vented cap and see what happens

 

Dude.... is the gas cap even on the car when you have your issue? Don't you think if it was a vent issue it would be eliminated as soon ans you remove the gas cap.(are you hearing air rushing when you remove gas cap after a good drive?) If you don't then I really really doubt its a gas tank vent issue. I replaced my gas cap once... dnt help. A lot of air still came in or out as I removed gas cap at gas station. The only thing that helped was unhooking the vent choose hat goes to charcoal canister. My metal line was clogged. No more air noises. But it just doesn't seem related to your issue of filling up with gas.

 

Update: It appears to be the inner tube connecting the gas tank and the gas cap section was bent and clogging up the flow. Once we straightened that out, didn't have the issue further.

 

Glad you solved it!