Quadrajet Sputter Turning Off
Thread Starter
Cruising
Joined: Aug 2022
Posts: 11
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Quadrajet Sputter Turning Off
Hello, my 7040203 quadrajet is causing a sputter when turning the engine off sometimes. I have the throttle blades practically closed and the idle at 800. My carb does have idle bypass air so this allows my throttle blades to be closed more and I bumped my initial timing up and used manifold vacuum advance. Is this normal for a quadrajet because my Holley doesn’t have this problem.
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Hello, my 7040203 quadrajet is causing a sputter when turning the engine off sometimes. I have the throttle blades practically closed and the idle at 800. My carb does have idle bypass air so this allows my throttle blades to be closed more and I bumped my initial timing up and used manifold vacuum advance. Is this normal for a quadrajet because my Holley doesn’t have this problem.
Thread Starter
Cruising
Joined: Aug 2022
Posts: 11
Likes: 2
Yeah I decreased my initial to 18 and have 32 total but it runs fine and I can lower my idle. 800 seems high but if I lower it then the car can stall if I turn my heat on. I have a stock 55 amp alternator but I’m thinking it may not be putting out enough amps at that low of an idle. Stock pulley sizes.
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Joined: May 2006
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Yeah I decreased my initial to 18 and have 32 total but it runs fine and I can lower my idle. 800 seems high but if I lower it then the car can stall if I turn my heat on. I have a stock 55 amp alternator but I’m thinking it may not be putting out enough amps at that low of an idle. Stock pulley sizes.
Did you change anything on the carburetor after the rebuild and did you tell them the specs of your engine?
What ignition system and what is it using to provide powet?
Thread Starter
Cruising
Joined: Aug 2022
Posts: 11
Likes: 2
MSD 8360 no ignition box. Carb was rebuilt to my combination, nothings changed. I haven’t tried driving the car and seeing if it won’t do it with the lower idle because it’s been so cold and I haven’t driven the car. I’ll test it out tomorrow and post the results.
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Joined: May 2006
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what year is the car?
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Race Director
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OK, where is the coil getting power from, the original double wire factory connection? If so, instructions indicate 12 volts required. The factory wires use a resistor wire that does Not provide 12 volts when running. That could account for your problem when turning on heater, voltage drop to ignition system.
Thread Starter
Cruising
Joined: Aug 2022
Posts: 11
Likes: 2
OK, where is the coil getting power from, the original double wire factory connection? If so, instructions indicate 12 volts required. The factory wires use a resistor wire that does Not provide 12 volts when running. That could account for your problem when turning on heater, voltage drop to ignition system.
Race Director
Joined: May 2006
Posts: 18,737
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