Stalling Help

[lowhd01]

Ok so im pulling my hair out here. My newly swapped 68 will start just fine and run great for about two minutes before it begins stumbling until it finally dies. It will restart after cycling the pump twice, only to run rough a die rather quickly. I can hear the pump running while it is trying to stall. If I give it time to cool and restart, it does the same thing running great for about 2 minutes. I have a new MAF, and 02 sensors. Computer was flashed previous to me buying it and was from a previous swap. I was thinking my return line may have been too small at 1/4" so i replaced with 5/16", did not help.

Setup:
99-F-body LS1/4l60
Inline fuel pump with Corvette filter
5/16 Fuel line supply and return
Stock behind the seat gas tank
Factory fuel pickup sending unit and utilizing the vent tube as return
No ODB

Thank you for your help!

[lowhd01]

I also cleaned the IAC. No Help

[sprint_9]

Couple things.

5/16 supply would be better off at 3/8, which is stock LS I believe, not sure if it matters or not but it might. Return at 5/16 is fine.

On the Corvette filter how do you have your supply and return plumbed, supply is the outside and return in the middle on the one side, and then the other side that has a single in the middle is to the engine.

You mention using your factory vent as a return, is there another vent? If not try running without the gas cap tight and see if it runs then.

[mongocanfly]

When you turn the key on without cranking how long does the pump, run...shouldn't be more than a few seconds..have you checked fuel pressure at the rails? Agreed with above on how the filter/reg is plumbed..my supply is 3/8" and return is 5/16" and I've had no issues

[lowhd01]

Ok so I just realized that I have the pump/filter backwards. I plumbed it with the pump after the filter (pulling through the filter as opposed to pushing). Fingers crossed this is my problem. I will update soon. Thanks for your help

[mongocanfly]

Glad you figured it out..this is how it should be stup..

[lowhd01]

Yep, definitely the problem. Thanks again!