Quadrajet sputtering

Bextreme04 said:

Here's a good one:

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Octane said:

Change out your old fuel filter if not done already

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fast 99 said:

Is it running on new fuel? It is doubtful the carb would operate correctly if it sat 12 years. However, as others have said you need to get the basics out of the way first. Also check the fuel pressure AND volume.

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SirRobyn0 said:

Start with the basics. Shut the engine off look down the throat of the carb, operate the throttle butterfly but hand and make sure each side is getting a good shot of fuel off the accelerator pump.

Then check the ignition timing. Set base timing to specification which should be on the underhood sticker. If no sticker is present shoot for 8 - 12BTDC. Check to make sure the vacuum advance is hooked up and functional. Check to make sure the mechanical advance in the distributor is functional, you can do that with the timing light but watching the light and the marks as you rev the engine looking for a total advance of around 30 - 35 or just pop the cap of the distributor and make sure the weights and springs are in place and move freely.

That's the main stuff. How does it run otherwise and how is the idle? When was the last time the carb was rebuilt? Is there a lot of slop in the throttle shaft? Generally throttle shaft looseness will cause other issues to but that or any other vacuum leak like from a rotted or broken hose can cause sputtering but would generally be accompanied by other issues.

When was the last tune up, a plug wiring that only breaks down when your stepping on the gas is technically a misfire but can feel like a sputter to some folks.

Feel free to post underhood pics, but your testing is what will find the problem in the end.

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AuroraGirl said:

If he has an original distributor and he also hasnt even checked the timing.... a tune up is in order AND cleaning your advance weights. that alone could be the sputter, but so could a long list already lsisted

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your distributor needs a cap and rotor probably so you can check the coil while transfering it and you can check yoru advance while everything is off, if they look like mine on the above, they are probably sticking

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Eighty5ov said:

I checked to see if a good shot of fuel was coming from accelerator pump and it was good.

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fast 99 said:

When the cap is apart make sure the ground strap is there. Also look closely at the 2 wires coming out of the pickup coil. Occasionally they will break at the coil and cause the motor to die or misfire.

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fast 99 said:

When the cap is apart make sure the ground strap is there. Also look closely at the 2 wires coming out of the pickup coil. Occasionally they will break at the coil and cause the motor to die or misfire.

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AuroraGirl said:

if it uses one that style of course. thats a 75 change i think

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Eighty5ov said:

So I did some work. I checked timing and it was bang on. Initial and advanced. The distributor advanced and vacuum advance worked. From what I was doing today, it sputtered when it was cold. But once warm I could gas it and was searching for sputter. I don’t know.

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