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Old 04-25-2004, 02:40 PM
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Vacuum Lines

On a quadrajet carb where does the vac line go to the tranny modulator and what is the tranny modulator.

ps. how do I tell if I screwed up my choke?????????????

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Old 04-25-2004, 03:36 PM
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The modulator line should be connected to manifold vacuum, either off the rear of the manifold behind the carb or I guess you could connect it to the rear (large) vacuum outlet of the carb.

Don't understand your choke question. If it was working before and it's not working now...then it's messed up.
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Old 04-25-2004, 03:40 PM
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One most GM manifolds with the Q-jet carb, the modulator hose goes to a "T" on the back of the manifold, directly behind the carb. The "T" usually also feeds the hose to the dash heater/AC controls and cruise control if so equiped. If that is not there, ANY port on the carb that has full vacuum at idle will be ok. Start the car, let it idle and pull off one capped pipe at a time and ck for strong vacuum.

As far as what the modulator does, it controls shift points, along with the internal governor and line pressure.

What is wrong with the choke?

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