72 Nova SS 350 motor will not idle?

[rally]

Guys my 72 Nova SS 350 Motor Will not idle unless i feather the gas pedal up and down. Adjust idle screw still will not idle. Advanced timing, still doesnt idel. Adjusted T-Slots on carb base, good. Checked fuel pressure, good. Timing good. Took apart Holley 750 DP carb and put all new gaskets on it. Checked PV, thats fine. Adjusted mixtures screws at a stop engine setting just to run car, engine still will not idle? Check for Vac leaks, couldnt find any. Is my HEI Distributor timing off a tooth? Any ideas i am missing? Thinking about pulling Distributor and reset rotor to number one cylinder again to see if timing is off. I have exhausted ideas. Any input help is greatly appreciated. Baffled.

[mag2555]

Give some history,did this just start after the Carb rebuild, or was the no idle the reason for the Carb work?
Have any other changes or work been done to the motor at the same time?
It would not be the first time that during Carb work the wrong metering block Gaskets where used.

[rally]

Give some history,did this just start after the Carb rebuild, or was the no idle the reason for the Carb work?
Have any other changes or work been done to the motor at the same time?

Just seemed like it got worse. Is the vac advance not working correctly?. I tried full port vac, still doesnt idle correctly. No other changes to the engine. Just out of storage recently. A performance shop went thru carb, i rechecked everything he did. Added all new gaskets again. Is it a vac leak somewhere i am missing. I may have to pull carb again and make sure gaskets are right.

[mag2555]

Feathering the gas pumps in fuel from the accelerator pump so I would say that your idle circuit is not working.
Do the idle mixture screws do anything?

[rally]

Feathering the gas pumps in fuel from the accelerator pump so I would say that your idle circuit is not working.
Do the idle mixture screws do anything?

I can run the engine only up to 3000 RPM or it will die out after lifting gas pedal.

[rally]

Wrong butterfly base gasket maybe? I changed that, wonder if its the wrong one.

[VMC]

Make sure you didn't accidentally install a 1 3/4" (850) throttle body gasket. The idle discharge holes are offset from the 1 11/16" passages and will block curb idle fuel flow.

[mag2555]

Just out of storage!

Do you have the proper fuel level as viewed in the site plugs?
Sock in gas tank gummed up with today's bad gas.
Cracks in old rubber fuel lines which makes it far easier for the fuel pump to suck air and not fuel.

[cv67]

any time Ive bad a car sit around awhile seems the fuel pump would go bad
are you getting fuel in your oil?
Longshot but sometimes its something simple

[rally]

any time Ive bad a car sit around awhile seems the fuel pump would go bad
are you getting fuel in your oil?
Longshot but sometimes its something simple

Checked fuel pressure. 7.5. Good. I may have to check that butterfly base gasket for the body and make sure its the correct one.

[rally]

Make sure you didn't accidentally install a 1 3/4" (850) throttle body gasket. The idle discharge holes are offset from the 1 11/16" passages and will block curb idle fuel flow.

Thanks Eric, i think you are right here. I bought the Holley rebuilt kit box with assortment of throttle body gaskets. its for the 4150 Holley carb. i have a 750 1969 date code double pumper. Soemthing isnt right after the change. Thanks i will do this to make sure.

[Geoff2]

Flooding by the sound of it. Needs the throttle open to admit more air for a combustible mix with the over rich mixture. Check also for a ruptured/leaking PV which will dump raw fuel into the manifold. Leaking gasket can do the same.

[rally]

Make sure you didn't accidentally install a 1 3/4" (850) throttle body gasket. The idle discharge holes are offset from the 1 11/16" passages and will block curb idle fuel flow.

This was the problem. I had my throttle body gasket positioned the wrong way covering up the small hole on the plate. To big of a hurry and not paying attention. Thanks again. +

[cv67]

Good find, would havebeen the last thing the avg guy would have checked, btdt.

[BigBlocksOnTop2]

Make sure you didn't accidentally install a 1 3/4" (850) throttle body gasket. The idle discharge holes are offset from the 1 11/16" passages and will block curb idle fuel flow.

This was the problem. I had my throttle body gasket positioned the wrong way covering up the small hole on the plate. To big of a hurry and not paying attention. Thanks again. +

Pretty easy to over look that. I've been the road too.