Quadrajet sputtering

[Matt69olds]

Start with the basics. Remove the air cleaner. With the engine completely cold, floor the throttle. Make sure the choke fully closes. Start the engine, the choke plate should open just a little as soon as it starts. If not, you may have defective choke pull off, or it may need adjusted. As the engine warms, the choke plate should open more, until it’s eventually open all the way. Fast idle speed should be around 1200-1400 rpm. Once the engine is warmed up, a tap on the throttle should disengage the fast idle.

 

[SirRobyn0]

Thanks for saying that @Matt69olds sometimes my brain starts to fly and I ask to many questions.

 

[Eighty5ov]

Well if it's only sputtering when it's cold maybe it's in the choke. So I guess I need that answered doe it only sputter cold?

If that's the case then we need to be looking at the choke, is it fully closed before cold start up?
It's an 85 so it's got an electric choke which will open up pretty fast, you can adjust it to stay closed a little longer though, how long did it take for the sputtering to disappear after starting it?
Is it running the factory air cleaner housing as is the thermac at least hooked up?
Is the heat riser the weighted mechanical type or vacuum operated, it's probably vacuum given the year. Make sure the vacuum hose is hooked up to the heat riser.
If that's all hooked up we can troubleshoot that stuff, but I had previously thought it was sputtering all the time, not cold only.

Since that wasn't mentioned earlier I had you check the ignition system which wasn't really needed, but on the other hand on an old engine it's good to check the timing anyway.

Yeah only when it’s cold. Once it was warm it was fine. Rev’d up nice had that q-jet screaming. The choke wasn’t closed all the way so I think that needs adjusted but it opened quick yeah.
It stopped sputtering after about 10-15 minutes. All lines are hooked up for vacuum. I’ll try again today and try to get video.

 

[Eighty5ov]

Start with the basics. Remove the sit cleaner. With the engine completely cold, floor the throttle. Make sure the choke fully closes. Start the engine, the choke plate should open just a little as soon as it starts. If not, you may have defective choke pull off, or it may need adjusted. As the engine warms, the choke plate should open more, until it’s eventually open all the way. Fast idle speed should be around 1200-1400 rpm. Once the engine is warmed up, a tap on the throttle should disengage the fast idle.

I’ve monitored this and on that kick down it’ll break up or sputter

 

[SirRobyn0]

Yeah only when it’s cold. Once it was warm it was fine. Rev’d up nice had that q-jet screaming. The choke wasn’t closed all the way so I think that needs adjusted but it opened quick yeah.
It stopped sputtering after about 10-15 minutes. All lines are hooked up for vacuum. I’ll try again today and try to get video.

Adjust it so it's fully closed when cold and I'd bet that solves your problem or at least improves it a ton.

 

[AuroraGirl]

Adjust it so it's fully closed when cold and I'd bet that solves your problem or at least improves it a ton.

does he have intact other emissions that could affect cold driveability or should he just look at carb

if just at carb

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[Matt69olds]

does he have intact other emissions that could affect cold driveability or should he just look at carb

if just at carb

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Years ago I found the fancy Kent Moore tool set for adjusting the choke flap in a swap meet. It wasn’t dirty, all the manuals were there, all the special tools and accessories were all in there place. It was a very old tool kit, it was in a metal box (long before the Kent Moore tools started coming in plastic boxes!!). I thought about buying it, for just a couple seconds. The 400 asking price was pretty step for something that I would probably never use.