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Choke Question

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Old 09-10-2016, 07:44 AM
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Choke Question

So I have a 1984 z28 with the 305 HO. I have to feather the gas when I try to start the car, then I have to rev it up until it reaches a good idle. I don't believe the choke is working the way it should but the light is not on once it starts. I have no idea how the choke on these things works? The only other information I can give you is the preheater hose that connects to the drivers side air duct is not present, I am going to pick one of those up today hopefully. Can someone explain what I need to do to make sure the choke is working the way it should or what I need to look for?
Old 09-10-2016, 07:57 AM
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Car: 1987 SC/1985 TA
Engine: 350/vortec/fitech
Transmission: T56
Axle/Gears: 3.27 9-bolt
Re: Choke Question

choke should be completely closed when the engine is cold. The throttle may need to be opened fully to allow the choke cam to fall and the choke plate to close and the fast idle cam to set.

Once the engine is started the choke pull off senses vacuum and opens the choke slightly.

As the motor runs the choke is provided with 12V, which goes to the choke coil and heats it. As the choke coil (bimetallic) heats up it opens the choke. Should take 5 minutes or so.

Once the choke is opened fully, opening the throttle will allow the fast idle cam to fall away and the idle to return to warm curb idle speed.
Old 09-10-2016, 08:08 AM
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Re: Choke Question

Thank you for your response. So for what reason would I have to feather it to get it running? Is that normal? Very seldom do I turn the key and have it start up, instead I have to give it gas a few times to get it started up? Maybe that's a normal thing, this is the first car I've had that wasn't 1999 or newer and am still learning.
Old 09-10-2016, 08:11 AM
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Re: Choke Question

The choke should close fully at any engine temp below 80°F or thereabouts.

Might need a new stat. (the round black thing) Might have to drill the rivets out to change it. If it's not full closed at 75° for sure (first thing in the morning, in a cool place like SC) then just go ahead and replace it. Might just need the linkage cleaned up real good. Might have bent or damaged parts. Shouldn't be too hard to figure it out.
Old 09-10-2016, 08:15 AM
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Re: Choke Question

Okay also, I have been told about all these ways to "Set the choke" from my father and father-in-law. This is an automatic choke though so I shouldn't have to press and release the gas slowly or press 3 times or do the hokey pokey or any of that right? I hate to bother you guys with stupid questions but I am an absolute rookie.
Old 09-10-2016, 08:20 AM
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Re: Choke Question

"Set the choke" = press the gas one time (takes the pressure of the throttle spring off the choke linkage so it can sproing itself into where it needs to go)

"Press 3 times" = pump a bit of fuel into the intake (there's a simple pump in the carb that pushes extra fuel out whenever you open the throttles) to give it a bit extra to start off of

FWIW, here's the instructions that came with the car. Note that these are the 83 instructions; that was before the "G" motor. However it's identical to the "H" motor in this regard so imagine that instead of "H" it says "H & G".





So yeah, there can be a certain amount of "hokey pokey" at times; we all were quite used to that for the century or so that cars existed before EFI was invented. Quite simple really. Even yer grandma was able to master it so she could drive to the store or whatever by herself back then.

Last edited by sofakingdom; 09-10-2016 at 08:24 AM.
Old 09-10-2016, 10:08 AM
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Re: Choke Question

Thank you! Instructions, now that's what I needed. I had so many people telling me different ways to do it. Didn't mean any offense to the homey pokey, just admitting my ignoance to what it takes to start these. Thank you very much for your help. I only have one part store so I am hoping they have that preheated hose there. Or I'm ordering online...
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