CCC Q-Jet Hot Start Issue after Rebuild
 

I've got a stock '84 L69 with the CCC Q-Jet. The local Chevy dealership rebuilt my carb last month, and with the rebuild most of my issues were solved (hard cold starts, severe hesitation while driving and starting from a stop light, and dying while driving).

The last issue that remains is ... The car starts fine when cold, after I drive for about 10 minutes I will turn the car off, and if I try to restart between 15 to 45 minutes later the car will rotate fast, but not start.

After about three or four cranks (5-10 seconds each time) the car will start (preferrably while pumping the gas pedal).

Once the car starts the choke light will flicker on and off for about 30 seconds and the idle will be eratic at around est. 450-650 RPM, and then the idle will pick up and stabilize around 550-650 RPM.

I have taken it back to the dealership numerous times, and they adjust the choke and tell me to bring it back if the problem persist. I usually drive my car, park it for several hours and then drive it to lunch or home, and the problem will not repeat for another month or two when I change driving habits, i.e. shopping trip, or cruise nights, and the problem arises again.

The choke plate opens gradually while the engine warms up, it is open while the engine is hot, and closes once the engine gets cold.

Also, I'm not sure if this is typical or not, but when I first start it after sitting for est. 4 hours or longer the idle will be about 1,700-2,200 on cold mornings and 1,200-1500 on warm mornings. I tap the gas about three times and the idle drops to 1,200 on either cold or warm mornings. Once the choke warms up the idle slowly increases, and once I tap the gas (one time) the idle drops to normal driving range (about 750 in park and 550-600 in drive).

Is this part of the famus L69 heat soak or vapor lock issue in the service technical bulletins?
Help! ???

The first problem may be fuel leaking out of the bowl. There are two plugs at the bottom of the bowl that often leak. Try flooring and holding the pedal instead of pumping it and see if it starts any easier. It is also possible the problem is not the carb but ignition, and pumping the accelerator isn't actually helping.

The high idle is a simple adjustment of the choke pull-off (vacuum break in factoryspeak). After first starting, the idle speed should drop with the first tap of the accelerator - not all the way down, but down some. The RPMs should drop to normal idle after about 5 minutes of running when the accelerator is opened off-idle.

Re: CCC Q-Jet Hot Start Issue after Rebuild
 

Can anyone elaborate on this?? My car will crank but not really start after it has reached operating temp. I'm ruling out many possibilities but found (last night) that holding the gas pedal to the floor will get it to start.

Trying to find out why...