New Camino on the block and emissions

[cwdaniel]

Greetings fellow gearheads. I've recently acquired an 83 El Camino into the
family, It was given to my son by his Grandpa. My son, who is 11 has been an El Camino fan for some time, so Grandpa surprised us all with giving him
one. An 83 model wouldn't have been our (my) 1st choice, but for free I
think we can make something out of it. The body and interior are in great
shape, but the engine has some issues. Unfortunately I see that it's
equipped with the pathetic early 80's GM attempt to meet BS emission
requirements. The wonderful Q-Jet with electronic controlled metering rods.
I'm in Arizona and the current emission testing for this car requires all
emission equipment to be present (present, not necessarily functioning).
This includes the computer and the 02 sensor. My question here is: has
anyone had any success getting a good carb (Q-Jet or other) on an early 80's 305 and through the prying eyes and noses of the smog dogs?

 

[joe_padavano]

I'll once again be the heretic and suggest that the electronic Qjet can be made to run very well - I've done it on my own 307 Olds motor. Keep in mind that the computer only controls the primary metering rods; the secondaries are mechanical (actually, controlled by the air valve) just like any other Qjet. There's also a green test connector in the harness right in front of the carb. You can connect a dwell meter here and monitor mixture control by setting the dwell to the 6 cylinder scale. Should be right around 30 degrees of dwell. Adjust the idle mixture screws to achieve this.

Note that this is a fairly complex carb and it must be rebuilt and adjusted properly, but once you do, it actually runs great. You also need to be sure all the other emissions systems are working properly and that the miles of vacuum hoses are in good shape and connected correctly. I had a problem where the air injection diverter valve was bad and pumped fresh air directly at the O2 sensor, which saw this as a lean condition and sent the carb full rich. Once that was fixed, the car passed emissions with flying colors and runs great. Also, be sure the throttle position sensor is adjusted properly. The primary side goes full rich at WOT, so the TPS needs to be properly adjusted.

I've seen these carbs used on engine swaps with big blocks and they still work great since you can change the secondary rods to your heart's content and the O2 sensor and computer take care of the idle and primary side.

 

[cwdaniel]

Back again!
The time has come to make this beast viable. I've rebuilt the Q-jet and I'm looking for some guidelines for intial idle mixture screw settings to get it going.

Also the electric choke seems to not be adding anything to the equation at start up. E Chokes have always been a mystery to me. Is the voltage to it variable by some heat sensing device to change the choke? If so what's sending the signal?