Easy diy gas venting system?

[mouserider]

charger 1971, 383, tunnel ram, 2x4 sniper efi.
My liquid/vapor separator is gone long time ago, as well as any canister or other hardware that was there back in the days. But anyway i guess it wouldnt work with my current EFI setup anyway.
So, what would be the easiest trick to get rid of gas smell and remove the evap lock possibility?
Currently all 5 ports are plugged , except one that is going up near the fuel filler cap. But smth telling me, im not an expert with this and currently im trying to locate gas smell problem (i can smell gas with every acceleration inside cabin with closed windows)

Thank you

 

[toolmanmike]

Many guys have fashioned a return system to stop vapor lock. They get a fuel filter with a return line and connect it to the gas fill tube in the trunk. You just need a place for the gas to get back in the tank.

 

[mouserider]

Many guys have fashioned a return system to stop vapor lock. They get a fuel filter with a return line and connect it to the gas fill tube in the trunk. You just need a place for the gas to get back in the tank.

oh, mb i missunderstand something, but how this will help preventing tank overpressure ?

 

[Doorkicker]

Ok... just so I'm clear, I'm assuming you're running a return fuel line or did you put in a deadhead pump setup for the Snipers?

If you dead head'ed... then your issue is likely under hood...

If you return line'ed... and you plugged up everything, then you're creating fuel tank pressure that could be your source of smell. Are you smelling it all the time or just when moving/driving or parked at idle?

Tell me about the fuel pump... is it in-tank or external? Do you have an after-market fuel tank?

 

[mouserider]

Ok... just so I'm clear, I'm assuming you're running a return fuel line or did you put in a deadhead pump setup for the Snipers?

If you dead head'ed... then your issue is likely under hood...

If you return line'ed... and you plugged up everything, then you're creating fuel tank pressure that could be your source of smell. Are you smelling it all the time or just when moving/driving or parked at idle?

Tell me about the fuel pump... is it in-tank or external? Do you have an after-market fuel tank?

i have a return fuel line from regulator back to tank,
i didnt plugged up everything, i kept one hose open and venting to atmosphere(i attached it next to filler cap)
fuel pump is external, fuel tank is original.
I do smell gas second after acceleration(even small one), i dont smell it while cruising or in traffic/idle.

Thank you!

 

[Hijinx]

Sounds like my setup. The way i did Sniper EFI, is that i installed a fuel pressure regulator (with return) in the engine bay with the return connected to it. On the tank i vented it using a roll over valve. So i have 1 line running from the tank to fuel pump to fuel pressure regulator to sniper, then the return to the fuel pressure regulator. I think it should work

 

[Doorkicker]

Not to divert from the topic, but you and @Hijinx talk about having a regulator... are you regulating the fuel before it gets to the Snipers or are you referring to the regulator in the outlet on the Sniper?

Ok... so @mouserider... a few more stupid questions from me...
Is your fuel cap vented or just the original? When you open the fuel cap do you get a "whoosh" like sound?

The vent you're referring to next to the cap... what is on the end of that hose/line? Something like a rollover valve?

Since you said you smell when accelerating... I have to ask, what's your AFR at idle, during acceleration, and WOT?

 

[mouserider]

Sounds like my setup. The way i did Sniper EFI, is that i installed a fuel pressure regulator (with return) in the engine bay with the return connected to it. On the tank i vented it using a roll over valve. So i have 1 line running from the tank to fuel pump to fuel pressure regulator to sniper, then the return to the fuel pressure regulator. I think it should work

Not to divert from the topic, but you and @Hijinx talk about having a regulator... are you regulating the fuel before it gets to the Snipers or are you referring to the regulator in the outlet on the Sniper?

Ok... so @mouserider... a few more stupid questions from me...
Is your fuel cap vented or just the original? When you open the fuel cap do you get a "whoosh" like sound?

The vent you're referring to next to the cap... what is on the end of that hose/line? Something like a rollover valve?

Since you said you smell when accelerating... I have to ask, what's your AFR at idle, during acceleration, and WOT?

Very correct questions, btw, by asking them you actually helping me out.

not sure about @Hijinx , but i have 2x4 Sniper Efi (double throttle body for tunnel ram) and this version doesnt have internal regulator, so i HAD to put one before EFI. And thats the one im referring to

i have vented cap(probably? ordered it 5 years ago, cant even remember) it doesnt make whoosh.
My current vent is simple a direct hose from tank to open air.

AFR is another issue, i still didnt tune snipers and im waiting hyperspark set to fix timing, AFR is not ideal, but not crazy off, and i smell gas even with slight acceleration, i get your point , but it cant be that much smell just because of a bit wrong AFR. especially in the closed cabin.

 

[Doorkicker]

Very correct questions, btw, by asking them you actually helping me out.

not sure about @Hijinx , but i have 2x4 Sniper Efi (double throttle body for tunnel ram) and this version doesnt have internal regulator, so i HAD to put one before EFI. And thats the one im referring to

i have vented cap(probably? ordered it 5 years ago, cant even remember) it doesnt make whoosh.
My current vent is simple a direct hose from tank to open air.

AFR is another issue, i still didnt tune snipers and im waiting hyperspark set to fix timing, AFR is not ideal, but not crazy off, and i smell gas even with slight acceleration, i get your point , but it cant be that much smell just because of a bit wrong AFR. especially in the closed cabin.

Ah! That makes total sense... I missed that you had the dual sniper setup. (I need to do that... or upgrade to a bigger EFI... my engine is needed more than the sniper can give at the moment... convo for another day

Ok... I get the vent you're talking about... that could be your issue. Under acceleration the fuel is sloshing hard and could be pushing the air out that vent.

Yeah... AFR has to be off to get a smell, but had to ask. I run hyperspark too... what's your timing issue?

If you're getting gas smell in a closed cabin... that actually has me worried. Try this... cram a pile of papertowels in the gas filler area, drive briefly or until you smell gas, stop and check the papertowel for liquid. Also, I'm assuming no leaks in the gas system (again, I should have started with that, but I suspect you already checked the return for leaks).

Also, my brain keeps going back to an underhood issue. Those fumes coming into the cabin from behind is a slightly more difficult path than from the engine bay. Just thinking out loud

 

[70chall440]

@mouserider did you retain the stock vent system (the 4 lines on the left/drivers side of the tank)? Those 4 lines go up into a space behind the drivers side rear tire, it is possible one or more of those lines is cracked and leaking. Each on of those 4 lines vent one corner of the tank and move them up above the tank, this is what I am planning on using to vent my tank in my 71.

 

[mouserider]

Ah! That makes total sense... I missed that you had the dual sniper setup. (I need to do that... or upgrade to a bigger EFI... my engine is needed more than the sniper can give at the moment... convo for another day

Ok... I get the vent you're talking about... that could be your issue. Under acceleration the fuel is sloshing hard and could be pushing the air out that vent.

Yeah... AFR has to be off to get a smell, but had to ask. I run hyperspark too... what's your timing issue?

If you're getting gas smell in a closed cabin... that actually has me worried. Try this... cram a pile of papertowels in the gas filler area, drive briefly or until you smell gas, stop and check the papertowel for liquid. Also, I'm assuming no leaks in the gas system (again, I should have started with that, but I suspect you already checked the return for leaks).

Also, my brain keeps going back to an underhood issue. Those fumes coming into the cabin from behind is a slightly more difficult path than from the engine bay. Just thinking out loud

Timing issue is that I have pro bilet and msd 6al-2 , and I can’t get static timing work, my timing light show that timing advances 15 degrees with static timing on, I’m tired of that and ordered a full hyperspark set. I will do a test with paper towel! Thanks, yeah I don’t exclude fuel leak, buuut, I don’t know how to check it? I’m looking at everything all looks dry, but it can evaporate quicker. Keep in mind I’m newbee)

 

[Doorkicker]

Timing issue is that I have pro bilet and msd 6al-2 , and I can’t get static timing work, my timing light show that timing advances 15 degrees with static timing on, I’m tired of that and ordered a full hyperspark set. I will do a test with paper towel! Thanks, yeah I don’t exclude fuel leak, buuut, I don’t know how to check it? I’m looking at everything all looks dry, but it can evaporate quicker. Keep in mind I’m newbee)

So, the wiring between the Sniper and 6al can be a pain. Once you get the Hyper you'll have a ton of control. I love it.

As for testing for leaks... there are dyes on the market you could try. Most are inexpensive additives (~$8), but are UV based, meaning you'll need a UV light to see it.

Of course, gas evaporates pretty quickly and even a small amount can smell strong... so you might not see a damp spot

 

[mouserider]

So, the wiring between the Sniper and 6al can be a pain. Once you get the Hyper you'll have a ton of control. I love it.

As for testing for leaks... there are dyes on the market you could try. Most are inexpensive additives (~$8), but are UV based, meaning you'll need a UV light to see it.

Of course, gas evaporates pretty quickly and even a small amount can smell strong... so you might not see a damp spot

the wiring is actually pretty simple, at the end of the day its only 3 wires between 6al and sniper (white points) and crank signal
but still, timing control works, but something adding advance, and i cant figure out who, so i decided to buy hyperspark and sell msd, anyway its almost same money.

i guess i will need to get those additives to sleep good)

So , back to the tank venting, seems like i just need to add roll over valve and vent through it and close all other ports, what about cap, should i keep venting on?

 

[Doorkicker]

the wiring is actually pretty simple, at the end of the day its only 3 wires between 6al and sniper (white points) and crank signal
but still, timing control works, but something adding advance, and i cant figure out who, so i decided to buy hyperspark and sell msd, anyway its almost same money.

i guess i will need to get those additives to sleep good)

So , back to the tank venting, seems like i just need to add roll over valve and vent through it and close all other ports, what about cap, should i keep venting on?

Good point. In all frankness, I only wired a 6a one time to the sniper, but for some reason it didn't work well for me. But hyperspark was always on the to do list anyway

Yep. Just put the roll over valve on and off to the races. At least that way you've improved safety, and may be even the smell.

It would be super cool to post back here or drop me a DM on what ended up working for you.

 

[68-500]

Personally I believe you can make a tunnel ram work on the street. Just not that max wedge port on a 383. You have very little air velocity in your intake. Its made for high rpm your cylinder head ports are made for lower rpm. Find a different tunnel ram with regular ports. Maybe a Weiand 1986?

 

[70chall440]

You can definitely make a tunnel ram work on the street, its been done for years. Look up junkerup on YouTube and look though his videos, he has one where installed a tunnel ram onto a BB charger and drove the crap out of it.