'85 Corolla:when is the throttle plate in the secondary venturi supposed to open?

Mar 24, 2007 2 Replies
M
1985 SR-5 w/ 4A-C engine. I know this sounds stupid, but how is the throttle plate in the secondary venturi supposed to open? Is it strictly mechanical, or is vacuum involved as well? I noticed yesterday, while I was trying to diagnose my overly rich condition (that I have another post regarding), that when the throttle is all the way open, the secondary one isn't.

Perhaps something is bent or misaligned in my linkage?



In my shop manual I can't find reference to an adjustment or even an explanation of how the second barrel is supposed to open up.



Thanks in advance.



-Mark Lum


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"Mark Lum" wrote in news:op.tpoloso88hg0ja@your-w04gtxld67:

It's vacuum-controlled. It will only open when the engine requires the extra fuel and air, such as under WOT at high engine RPM.

If it opened too soon, you'd lose intake vacuum under the throttle plates, and the engine would stumble and hesitate.

If the car's running well and has good power at high RPMs, the secondary is fine.

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L

If it's like my 4-door FWD 1986, the secondary is operated only by that big vacuum diaphram on the side of the carb. Here are the only adjustments I could find for the secondary:

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