i have a 305 with a quadrajunk. i just put in a new heater core, and removed the air conditioning. i fire it up for the first time since the modifications, starts perfectly like always. i let it run while i refill the radiator and stuff, it has been running for about 10 mins, and i go to kick it down, and i cant. the electric choke wont close it seems like. so i shut it off, and it starts dieseling violently, so as fast as i can, i pop the hood, take off the air cleaner, and put my hands over the carb to smother it, and it shut off. that is when i notice this:

the top thing, which i beleive is the choke, is staying open about a 1/4", instead of being closed. i think that is letting the air in fuel into my engine, making it diesel. if i shut the choke with my hands, it will stop dieseling right away, but when i let go of it, it will just pop back open. HELP!!

 

ok...what the hell is 'dieseling'...how can your car become a diesel...this makes no sense whatsoever to me...maybe I'm just lost

Anyways, the primaries are open in that pic, totally normal (I've owned 3 4-bbl carbed cars). Air is suppose to mix with fuel? I'm confused

 

dieseling is when the car runs with out spark (for instance when i shut it off) like how a diesel engine runs without spark.

 

i put the smog pump belt back on, and it's fixed...

 

wtf, the smog pump shouldnt be causing that issue. i think that typicly dieseling with gas engine is caused by the ignition system. however, that doesnt sound like your issue. is it a manual or electric fuel pump? what octane are you running?

and you have the same wheels and color of my car. weird?

 

yeah i was shocked as well when that fixed it, but hell i aint complaining! when i boguht the car it dieseled when i first brought it home, and i corrected the timing when i changed plugs, wires, and the cap. it had been fine since, that was like 15 months ago. so i knew it wasnt the ignition timing. it is a manual pump, and hmmm what octane... i filled up on 93 the other day, got down to 1/4 tank, and filled up with regular. i dont know, you do the math haha. are your wheels aluminum or chrome? what brand are they? mine are american racing chrome finish. i got them for last christmas from my father, who had them originally on his 84 firebird. so i put some fat tires on them, and i like em

 

Ditch the quadrajunk! Get a good Edelbrock 600cfm carb and intake manifold, that fixed many of the dieseling problems my friend was having with his '76 vette, and you get POWAAA!!!

 

yeah i already have a edelbrock performer 600 carb, i just need to buy the intake for it.

 

Have you checked vaccuum, spark quality, and trace back from the heater incase you knocked something off, or if there is a leak from the carb not being tight enough, valve timing, broken spring on the butterfly?, if all else fails bring out the fine tunig tool, a BFH. 75lbs should be sufficent.

 

Do you have carbon build up on your valves and plugs?