Cutting out at WOT

As some of you know I rebuilt a quadrajet 795cfm carb and put it on the 460 in the Bronco, and have been working on getting the jetting dialed in. Well the jetting on the primaries is pretty close, just a little on the rich side, but either the secondaries are still really lean, or the carb is running outta fuel (float adjustment). When I go WOT it runs strong 'till about 3000rpm, then I think the secondaries start opening and the engine starts stumbling/surging and my O2 sensor gauge starts bouncing to full-lean.

I know the float is CLOSE to right if not perfect, because I checked it when I rebuilt the carb. I THINK my problem is I need richer secondary metering rods, and I've got some on order so I should find out for sure soon... but what I need to know is, if the problem IS a poorly adjusted float or restrictive float valve, how would I know? It seems to me like it would run strong for a few seconds before it started sputtering if it were running out of fuel. Would it feel like the lean surging like I am feeling, or would it feel like the engine totally shut off for a second and then comes back to life for a second?

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'86 Bronco fullsize, 460, E4OD, 6" lift, 35" BFGs, 4.56 posi

'85 Ranger, 340hp 289, T5, Cobra wheels, 245/45/ZR17, 4.10 posi 7.5"


<font size=-1>[ This Message was edited by: Motorhead on 5/23/05 11:38pm ]</font>

check fuel filter,or change it.

did that, the filter on the fuel tank is only a few months old, the post-pump filter is clear, and the filter in the QJet is brand new. Also I didn't have this problem with the Edelbrock 750 so if it were a filter it would have to be the one IN the Qjet, which I guess I could remove to see if it changed the problem any... I'll save that for after the metering rod change, if it doesn't fix the problem.
[addsig]

I moved my filter to post pump and thats when I was starved after 4000 rpm,moved it back to pre filter,and it ran fine(stock block mounted pump)If you just moved your filter to post pump.I'd be moving it back.

Ok well I drove it around a little and I'm leaning a little more toward fuel starvation, because if I'm rolling about 25mph and stomp on it, it downshifts to first and pulls clean and hard from 4000 to 4500 then shifts and then starts sputtering. I have a regular filter back at the tank, then it goes to the mechanical pump, then through one of those cheap clear glass Mr. Gasket chrome filters, then into the carb where it goes through a small pleated paper filter. Yeah I know, that's a lotta filtering. As I said the one back at the tank is pretty new, and the previous one was good for about 20K miles so I'm sure it's fine. I cleaned the glass/chrome filter, although it was pretty much clean anyways, and when I blow through it it's not restrictive at all. Then I took out the paper Qjet filter and it's clean, but it's a b1tch to blow through, so I think that might be where my main restriction is. I left that filter out and put the carb back together (2 filters should be plenty anyways) and I'll take it for a test drive tomorrow hopefully to see if it's improved any. Got my fingers crossed [img]/phpBB/images/smiles/icon_smile.gif[/img]

P.S. you know you're a true gearhead when you don't think twice about putting your lips on a gasoline soaked fuel filter [img]/phpBB/images/smiles/icon_spin.gif[/img][img]/phpBB/images/smiles/icon_lol.gif[/img]
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'86 Bronco fullsize, 460, E4OD, 6" lift, 35" BFGs, 4.56 posi

'85 Ranger, 340hp 289, T5, Cobra wheels, 245/45/ZR17, 4.10 posi 7.5"


<font size=-1>[ This Message was edited by: Motorhead on 5/24/05 10:07am ]</font>