[helmerrock]

I’m running a 69 Quadrajet with divorced choke. Runs well. For a cold start, I hit throttle once to set choke then start. Starts right up and runs on fast idle. Problem is that it doesn’t stay on fast idle very long so after a short time if I hit throttle, the fast idle drops off. The choke spring is still holding choke plate closed until it hears up. I need to figure out how to adjust to keep the fast idle cam engaged a bit longer during warm up

Any ideas? Thanks

[Kenth]

This may help some:

[grivera]

This is a good read on choke adjustments:

https://www.chevelles.com/threads/ad...roach.1131913/

[Formulabruce]

Pass side, adjust high high idle stop screw against cam, you may want a new spring in your choke stove if it's not closing choke enough.

[Schurkey]

Originally Posted by helmerrock

I hit throttle once to set choke then start. Starts right up and runs on fast idle. Problem is that it doesn’t stay on fast idle very long so after a short time if I hit throttle, the fast idle drops off.

That's how it's supposed to work. Verify your actual fast-idle speed, the choke pulloff adjustment, the choke-blade-to-fast idle cam adjustment, and the choke coil tension.

Originally Posted by grivera

This is a good read on choke adjustments:

https://www.chevelles.com/threads/ad...roach.1131913/

[Elvis Voice]Thankyew, thankyew verra much.[/Elvis Voice]
Most of the spacing errors were introduced during a "forum upgrade", and they won't let me fix 'em.

The point being, the fast idle SHOULDN'T be on the highest step of the fast idle cam for more than a few seconds--long enough to stabilize the engine RPM, and then you touch the gas pedal to rotate the cam to the second-highest step of the fast-idle cam.

You surely wouldn't want to drop the auto trans into gear with the cam on the highest step, or idle along at 20-something miles per hour.