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Old 08-02-2012, 06:22 AM
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4.3 v6 stumbles and dies

Hey everyone, i have a 1991 carbureted 4.3 v6 (Edelbrock intake). It has Holley 465 CFM carb. When i put it in gear, it stumbles and dies. I have the timing set at 8 degrees and have the fuel pressure at 4psi. Also, the throttle is very sluggish. Any thoughts on what could be causing this??? Thanks for your help!

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Old 08-02-2012, 05:50 PM
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Raise the pressure to 6psi, thats what holley calls for.
Do you have vacuum advance?
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Old 08-02-2012, 06:02 PM
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Bump your timing up to 12-14*.
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Old 08-02-2012, 07:09 PM
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With vacuum advance disconnected and plugged, set the timing at 12 degrees before top dead center. Lock distributor. Reconnect vac advance. Make sure you connect it to manifold vacuum source. This is any source on the carb that pulls vacuum full time, including at idle. Recheck timing, it should be 18 to 24 degrees before top dead center. If it's still at 12 then the vac advance is likely ruptured and will need replaced. When you connect it right away it will idle up. Lower the idle speed down to around 700. Then reset the idle mixture screws. With the timing set as low as you have it now the idle adjustment is so far open the throttle blades are off the idle circuit which is forcing it to idle off the main boosters. I just converted my hot rodded 4.3 from TBI to carb. I also converted it to Vortec heads and a marine intake with a Quadrajet sitting on the top and the timing specs I gave are what we use on small block chevys which are really no different tune wise than the 4.3's. I used them on my 4.3 and now when I tap the key it starts. Soon I'll have the rest of the parts I need and I'll be able to test drive it finally. Once you get the timing set correctly you'll notice it has alot more power and it'll get better fuel mileage as well.
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Old 08-03-2012, 12:23 AM
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Sorry for the time delay Iím in Africa. Over the weekend I will defiantly bump up the fuel pressure and reset the timing . at this stage the vacuum is connected to the carb but I will change that. Thank you for your reply hope I can sort this thing out.
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Old 08-03-2012, 05:03 AM
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Some holleys can handle up to 9 psi. Some can't handle more than 6. In my experience any time I moved one up past 6 it started flooding. Move yours up to about 5 1/2 psi as a safe point.
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Old 08-03-2012, 05:23 AM
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Thank you will do will let you know on Monday how things went
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Old 08-10-2012, 01:44 PM
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update? how'd it work out?
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Old 08-13-2012, 08:53 AM
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Running like new thank you every one
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