Quadrajet tuning success

[ChevLoRay]

You gotta be careful when you turn those idle air screws. A lot of them have been adjusted over their lifetime and can cause idle problems when they become grooved where the needle seats in the throttle body. At that point, you are not getting the setting you are trying to achieve.

If you suspect a vacuum leak, simply put your hand over the open carburetor. If there is a leak, it should smooth out. If no leak, it should die when you deprive the carb of any air.

I used to seat them (gently), then back 'em out 2.5 turns as a reference point. Then, I'd use the Sun machine to monitor the engine conditions as I sought to balance the idle air settings.

[6D8_C10]

Originally Posted by ChevLoRay

You gotta be careful when you turn those idle air screws. A lot of them have been adjusted over their lifetime and can cause idle problems when they become grooved where the needle seats in the throttle body. At that point, you are not getting the setting you are trying to achieve.

If you suspect a vacuum leak, simply put your hand over the open carburetor. If there is a leak, it should smooth out. If no leak, it should die when you deprive the carb of any air.

I used to seat them (gently), then back 'em out 2.5 turns as a reference point. Then, I'd use the Sun machine to monitor the engine conditions as I sought to balance the idle air settings.

Thanks I will give that a try.