Quadrajet Problem Solving > Diagnose a Quadrajet carburetor problem

another idle issue

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canadian nascar:
Hi Guys,
I have a 301t with 8.5 compression, 262 comp cam, stock carb 276 export

I have a a/f gauge that I am adjusting to,
stock hei with accel coil
made the carb specs to Cliff's recipe #2, Cliff suggested this
-14 vacuum in park
timing dist is locked right now at 18* with 25* vac adv.
I have gone though the lines numerous times looking for vacuum leaks

I the car idles but higher rpm, 800 in gear to keep it running, sometimes feathering the throttle, if I put the a/f to 15-1 it will be hard to start and puff fuel out the exhaust when it does start. Really gassy
To make the car not puff smoke I lean it out to 17-1 a/f, it starts better and no puffs of smoke, same rpm as above, still gassy

I bumped the adj vacuum adv just before I but it away to 25* and it made my vacuum increase, I thought this is a good thing and would like to give it some more vacuum adv. but I was told that is not right. The gassy is less with more adv and like i said gave more vacuum.

it will not run without vacuum adv.

when I start it cold the exhaust smells like it should for a minute or two.

what other info is needed and what can I do ?

Kevin

77cruiser:
Have you tried adjusting the idle to the highest vacuum? It will end up a lot richer than 15-1.

canadian nascar:
so you are saying just to adj the idle speed screw to highest vacuum, in my case slower rpm?

thanks

Cliff Ruggles:
It may not like the Comp cam.  Those cams idle "quirky" in larger engines with more compression than the little 301. Never liked them much and 110LSA is just all wrong for a Pontiac engine, IMHO.

If you are having to run that much timing at idle to get it to stay running, for sure it either needs more fuel down to the mixture screws to offset the poor signal to the carb.  I'd start there, and see if you can back the timing off some and get the throttle plates open a little further at idle as well.......Cliff

77cruiser:

--- Quote from: canadian nascar on March 14, 2016, 09:02:24 PM ---so you are saying just to adj the idle speed screw to highest vacuum, in my case slower rpm?

thanks

--- End quote ---

No the idle mixture screws.

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