[87fubar]

ok heres were im at 75 firebird 400 with p4b intake 1406 carb hedman headers 1chamber mufflers inital timing set at 12bt has a cheapo kragen elec fuel pump runs good till you stomp on it like your passing picks up good for like 5or6 sec then it falls on its face

[techinspector1]

Install vented fuel cap.

[87fubar]

its got 1 of those locking gas caps. should i plug the line at the tank that would go to the vaper can its got no smog stuff on it any more. i realy havent worked with any thin with smog stuff

[techinspector1]

I was just throwing out the thing that's hardest to figure out. I've seen it in other threads where they finally figure out that the fuel system, as a result of being totally closed off, is going into a low pressure or no pressure mode or even a negative pressure mode, supplying little or no fuel to the carburetor. The unvented fuel fill cap has been found to be the culprit with some other fellows, although there are many things that could generate the hesitation.

[ericnova72]

Sounds to me like inadequate fuel pump, restricted or restrictive filter, tank sock, or fuel lines.

Somehow the fuel system can't keep up with WOT demands, uses up what is in the carb with not enough coming back in the bowl to keep up.

[87fubar]

should i try putin the factory type pump back on. the po put the cheapo pump to replace the factory 1 when the crate motor went in

[87fubar]

what else should i look into while i wait for the factory pump to be shiped out