Chevelle Tech - View Single Post - New Quadrajet, idling problems
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post #1 of (permalink) Old Aug 5th, 13, 4:13 PM Thread Starter
Adam G
Tech Team
Join Date: Nov 2008
Location: New York
Posts: 242
New Quadrajet, idling problems

Just installed a Shawn Murphy rebuilt Quadrajet on my brother in laws í70 GTO (I know, not a Chevelle). Itís the original 400 motor, original ignition system, (which means points) and the motor has a mild cam in it Ė thatís it, no other upgrades.

I canít seem to get the motor to idle smoothly. Iíve played with the idle mixture screws and seem to have them at the point which the engine idles the highest (getting a vacuum gauge tonight to check manifold vacuum), but the motor still idles rough.

Possible causes?:

- Could the vacuum advance canister not be getting enough vacuum? It currently connects to a vacuum ĎTí fitting rather than getting its own direct vacuum fitting on the carb.
- Could the timing just be off given the new carb.?
- Could the motor possibly just need a tune-up (plugs, cap, rotor, set the points, etc.) given the new carb installed.

The motor ran smooth at idle with the old Quadrajet, but someone over the course of the GTOís life had installed a Chevy carb. and my brother in law wanted the correct front-in fuel line Quadrajet used on all Pontiacs.
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