Going nutts. I have an 84 Scotsdale 4wd with 350, headers(wrapped), 2.5 duals, this is a secondary vehicle or toy to me. I have always loved these trucks owned and built several over the years. I have never come across this problem. Now this 350 has sr torquer heads and 270HR cam with 750 spread bore Holley and it ran good for about a year and it all started. When cranked cold fuel pressure is great, but dies out and will adventually vapor lock at operating temp. Since this started I have: -wrapped my rt side exhaust that runs along side my fuel lines (my fuel are not hot at all when fuel pressure dies happens) can touch with hand -installed an electric fuel pump(results are the same electric or manual) -every fuel filter is new -I run off the rt fuel tank which I have dropped and replaced the fuel pick- up screen the only thing that hasn't been replaced is the dual tank switch over valve which works and the fuel line going to it Has anyone had this problem can anyone help?
It is fixed for now. The switch over valve for the fuel tanks or one of the lines must be cracked and sucking air. I only run off the right tank anyway because I haven't dropped the left to change the pick up screen yet. When you think that you have rust in your tank it's probibly the screen coming apart. I bypassed the valve and use only the right tank and I'm running 3 pounds on the regulator. I've been thru 2 tanks of fuel without any trouble.
( or the dual tank valve suck air or not open enough to let enough fuel out). So you lot 2 pounds of fuel pressure just enough cause that problem. Only need 5 to 6 psi fuel pressure to run good un less you got a really wild cam.
I had a 78 with dual tanks and it would die with half full tanks. Turned out to be the hoses from the tank to the lines. Changed out the hoses and never had any problems. Chris
