Cliff's Quadrajet Parts and Rebuild Kits
Quadrajet Problem Solving => Diagnose a Quadrajet carburetor problem => Topic started by: baxternick on November 27, 2016, 08:46:02 AM
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I have a Cadillac 500 with a quadrajet installed in my 54 Chevy. The car ran perfectly for the most part. The only issue was it would run out of fuel above 4300 rpm. I already put in a new tank and 8an lines. So next I just installed a RobbMC performance 1100 HP pump and a Holley regulator. The regulator is currently set to 6psi. When I first start the car from cold it runs great while choke is engaged. Once I drive it around a few minutes the car falls on its face when braking or when sitting at a light even in neutral. My AFR drops to 10.8 and lower when this is happening. The new pump and regulator lack a return line that I had with my factory pump. I am wondering if the lack of return line is causing this? I was also thinking the fuel pressure is to much at 6? My final guess was Float Level was to high. It is set to 1/4". The carb currently has 77 Jets, 53M Needles, J Hanger, CE Rods, and a .145 Needle seat. The fuel pump upgrade cured my fuel starvation at WOT, but seemed to cause this issue now. Thanks for any input in guys!
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I'm thinking you might be right on the edge with 6 psi. & a .145 seat. Does the pressure creep up while driving.
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I like to see a return line with any sort of mechanical or electric high capacity pump. They can and will cause issues without one.
It's one of those things that you will get a lot of opinions on, my experience prefers a return line set-up.....Cliff