Gas tank issues and fuel cut out

[Badger69]

Looking for some opinions before I go hunting.

Build is stock LS2 from a TBSS with 4L70e and a 3600 stall.

Gas tank is under bed, is a Yogis 15 gal. Filler is flush with bed. Tank is vented in right rear of bed towards top corner.

When the tank is less than half, gas spits out of the vent and it tends to build up pressure.

A second issue is when I am wide open on the throttle and in second gear it feels like the fuel is cutting out. The truck stutters.

Any ideas? I have my own theories, but want to see if someone else had this figured out.

[mongocanfly]

if your tank is vented properly you shouldn't be building tank pressure....
if your vent is to low under the bed and behind the tank its possible that with forward momentum gas could blow out the vent....

cutting out while accelerating could be the pump sucking air due to fuel level vs fuel pickup placement causing cavitation,, pump not big enough, or it could be the tune.....I'd put a pressure gauge on it and see what its doing

[homemade87]

This is just a thought . I am not familiar with that gas tank . If there is 3 ports on the tank , gas feed , gas return , vent . If you have the vent and return ports reversed it could very well do this . The return tube should go to the bottom . If the the vent is hooked to this it could push fuel from the bottom of the tank out the vent . Your vent should be high enough if it gets close to the top of the bed . This would not let it vent the pressure with out pushing gas with it to the top of the vent . Be worth checking.

As far as the cutting out , it may be a tune thing . I would check the fuel pressure first and eliminate some basics . Also if the tanks is full does it do it . If not it may be a baffle thing in the tank not keeping fuel to the pump as Mongo has said .

Hope this helps on some things to check .

[Badger69]

Thanks guys. Appreciate the comments. Your thoughts were the same as mine. One really odd thing to me is that this did not happen at first. It began to happen the second season i drove it.

My vent is definitely on the right port and is a lot higher than my tank. Almost wonder if i got some crap stuck in the vent line. Might try changing the vent tube just to see.

I'll toss a pressure gauge on it and see what it reads then go from there.