automatic choke wont turn off...

[cocheeze]

well, after driving you guys crazy with questions for a week, i think i finally know my problem...

background: 1988 tercel, the timing is perfect, the gas delivery is fine, the spark is good. compression leaves something to be desired, but it is also okay.

i noticed that i can start the car, but i cannot get it to idle down, even after removing the hoses from the vacuum advance. once i turn off the engine, it refuses to start again (until the engine is cold again).

when i look down the mouth of the carb., all i see is a cylindrical plate blocking the opening.
i was told this is the automatic choke, and that it would retract after the car warms up. it does not do so.

my haynes manual says that in order to test the automatic choke you should take it to a repair center (some manual!)...

does anybody know how i can test it for sure?

thanks!

casey

[NickR]

What about page 4-12 of the Haynes manual? "Feedback carburetor inspection" section 6. "Check the Electronic Air Bleed Control Valve"? That would be my guess about what is wrong with your automatic choke.

[Donald]

Originally Posted by cocheeze

when i look down the mouth of the carb., all i see is a cylindrical plate blocking the opening.
i was told this is the automatic choke, and that it would retract after the car warms up. it does not do so.

casey

Haynes Manual: Page 4-1, Feedback carburetor - The fuel / air mixture is mechanically controled.

That is what that cylindrical thing does, it mechanically controls the fuel mixture. It is not the choke, it is the vacuum slider and responds only to manifold vacuum. It varies the venturi opening in relation to the intake manifold vacuum to keep the fuel mixture correct. That way when you go suddenly to wide open throttle and the butterfly opens all the way up, you do not get a bogging down caused by a lean condition.

It is the best and worst part of those carburetors. When it works, it makes for a very smooth throttle response, but if it gets gummed up, or has a vacuum leak, it becomes the death of the carb.

Haynes manual page 4-13 has an exploded view diagram of the carb. Top right corner of the diagram there is a thing called a compensator, I believe that is the enrichener (choke) mechanism.

What NickR said about that electronic air bleed control valve is correct, it could be your problem or a part of it too.