Quadrajet Problem Solving > Diagnose a Quadrajet carburetor problem
Idle problem
dlphil10:
I changed distributor springs and it's much better but I'm still thinking carb issues. The power piston moved freely when I installed it and the rods seemed to be at the right height. After tweaking the dist. springs it will bog under moderate load and when I back off it a little it speeds up and I can give it more throttle. It's consistently around 12inhg in park amd 8-9 inhg in gear.
dlphil10:
I looked at the carb and the primaries are open well into the vertical transfer slots and and past the horizontal transfer slot. I can open up the idle bypass air and close the primaries more, correct? Would having the primaries closed further bring up idle vacuum?
Cliff Ruggles:
Are you seeing any nozzle drip at idle, if not it doesn't need any more bypass air?
Makes no sense why the engine would not accelerate the carb has plenty of jet in it, and metering rods are 4 sizes richer than what it came with.
Maybe a fuel flow or delivery issue, filter in backwards or something odd going on?......Cliff
dlphil10:
Is nozzle drip very noticeable? I've looked down at the nozzles with a flashlight several time and haven't seen anything...
The acceleration is a lot better. I have it idling around 700 in gear and I noticed it runs much better with the mixture screws turned out at least 1 turn from highest vacuum.
I don't have good off the line acceleration and I'm wondering if that could be from having the primaries open too far. I'm trying to maintain the idle speed, but see if regaining transition slot could help. If I give it gas it chokes then picks back up. The accelerator pump shot is strong and healthy. A vacuum gauge shows when the throttle is cracked vacuum plummets to 5inHg.
Maybe it's just the highway gears and automatic that I'm fighting?
dlphil10:
Plugs look good creamy tan color.
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