Quadrajet Problem Solving > Diagnose a Quadrajet carburetor problem
Sudden extreme rich condition
MP81:
So I got the new choke the other day and decided to put it on today.
After installing, it exhibited the exact same symptoms as before - running stupid rich and at high idle. So I decided to replace the connector - the voltage readings I got were hit or miss on the terminal, but were fine at the wire.
Put the new pigtail on, and as soon as I keyed on, the choke closed entirely and now the car won't start at all.
I made sure the fast idle cam (I think it is) was inside the enclosed part of the "tang" of the clock spring, and then rotated back to roughly vertical (so the connector is on the bottom, as my other choke was). Did I need to rotate it more or something? Or is that how it's supposed to be - I do remember the choke plate at cold start being closed prior to all this goofiness (maybe the carb was flooded from it running so rich just a few minutes prior).
Cliff Ruggles:
Just leave the key on for a minute or two as the engine is warm enough it isn't like the fully closed choke flap.
Also verify that the pull-off is unloading the choke correctly on a cold start.
The basic setting for the new choke is to install it and rotate counter-clockwise unit the choke flap just fully closes. There is a fine line on the choke that should be at or close to the center mark on the choke housing and well within range from rich to lean.
Make sure when adjusting the choke that the throttle is open some or the fast idle cam/linkage may prevent the choke flap from closing......Cliff
MP81:
So I went ahead and set it up that way yesterday - turned it just until the choke flap closed. This put the mark (on the top of the choke) within the little set of dashed marks. My original choke had the line at about the 2 o'clock mark, computer to 12 o'clock, however, so the choke did not appear to be rotated by about 45 degrees (where the connector sits, was right at 6 o'clock compared to about 8 o'clock now).
The car did start, so it was probably just flooded, but that choke never opened more than 1/4" of an inch. How would I know if the pull-off is causing this (or could it not)?
I measured voltage at the connector (I believe this is the factory choke wire) and I got right around 10.5-11V.
Cliff Ruggles:
The choke pull-off unloads the choke at initial start-up, it has nothing to do with how the choke is adjusted.
Vacuum test it to make sure it is working?
I would also test the electric choke by grounding it on a negative battery post and attaching a positive wire to the connector from the positive post. It should heat up in about 2-3 minutes and the coil will move so reference the initial position and watch it move as it heats up.
Once you verify both parts are working put them back in place and set the choke so it just closes the choke flap. Make sure the throttle is open so it can do this or the mechanism will lock out the choke and prevent a correct setting.
Once the choke flap is fully closed apply the pull-off with a vacuum pump or just fully compress it by hand. The choke flap should open some or it will need correctly adjusted as well. It only needs to open enough so the engine doesn't flood out on a cold start, and can be fine tuned to perfection with a little effort if you move quickly after the engine initially fires up.....Cliff
MP81:
I meant more that can the pull-off prevent the choke from opening?
It does seem to have proper vacuum as you can only move the pull-off in/out after the engine has been off for a while and the vacuum bled off. Otherwise it's not really possible to move.
The choke flap does open some, so I don't think the pull-off is causig my issue - but rather a choke only getting 10.5-11V not heating up fully - though I'm not entirely sure how that suddenly is a thing (voltage at the battery is fine).
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