i have a 1985 trans am.i recently change out my qjet for another qjet with eletronics hook ups that came off my friends 83 caprice 5.0.my old qjet didnt have eletronic.i have an vacuum advance distubutor.i check all vacuum lines for leaks.it idles at 550 and when i gas it ,it bogs down.Should i advance the timing a little? what are some suggestion?

 

If your old carb was non-computer controlled, you probably shouldn't be putting a computer controlled carb in its place; you'd be much better off rebuilding your old one instead. A rebuild kit can be had for thirty bucks or so and can be accomplished in a couple hours.

I haven't dealt with the CC carbs personally, but I know the ECM adjusts the mixture and controls the timing. Given this, your fuel mixture is probably off and there might not be a vacuum port available with the correct amount of vacuum. 550 idle speed is on the low side, IIRC factory spec is 650 in drive for an automatic and 750 in neutral with a stick. Adjusting the idle speed might be all it takes to fix the bogging. If not, check your base timing, and try different positions on the accelerator pump for a bigger or smaller shot of gas when you step on it.

Dieseling is usually caused by carbon buildup in the combustion chamber; if it only started after installing the new carb you just might be running pig-rich. Either run a cleaner like Seafoam through or, keeping one hand on the throttle, lightly mist water into the carb with the engine running. You'll probably see black streaks on the ground under the exhaust pipes. Check your spark plugs, clean or replace as necessary.