Quadrajet Problem Solving > Diagnose a Quadrajet carburetor problem

Fuel out of the EGR vac fitting

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damoroso:
Cliff,

You and I have spoken several times, I have the 81 vette in FL with the big block in it running the original E4ME off the small block.  I've rebuilt it to your specs and you put the plugs in the body.  I've been working to get this thing completly dialed in, most recently I changed the VAC on the distributor because I couldn't get the thing to idle consistantly.  Some times it'd be good, often it'd start to slow and stumble (in gear only) at a light and act like it was getting flooded.  As it turns out, there wasn't enough vacuum to hold the VAC that was on the GM high perf HEI dist.  So, I changed to a VC 1862 and that's worked out, but there are still two issues. 

1st, I've found fuel at the original EGR vacuum connection on base plate at the rubber nipple that's now on it on serveral occasions.  Where the heck's that coming from?  And 2nd, it's running out of fuel when I hold higher rpm's, like holding second gear at about 2500 rpm, then going to WOT.  By the time I get to about 5000 (doesn't take long at all) it'll fall on it's face out of gas.  If I take my foot out of it for just a couple of seconds, it's good to go.  This only happens at higher RPM with WOT.  I have a Edlebrock 140 GPH pump on it, with a Holley regulator running 5.5psi.  There's no fuel sock in the tank, the lines are clean, and there's a 40 micron filter between the regulator and the carb.

Any thoughts on the wet EGR fitting and the fuel issue would be greatly appreciated.

Thanks,
David

Cliff Ruggles:
That fuel system should keep up with it.  I would increase the fuel pressure to 6.5 to 7 psi.  If it still runs out, install a larger fuel inlet seat, .145" or .149".

The only way fuel can get on the outside of the carb at the front fittings, is leaking at one of the front plugs over a cross-drilled passage.   There are two on that carb nearly as I can remember.

This would be quite rare, as I've never to date seen any of those carbs leak at either one of those plugs, and it's pretty rare to have them leaking at any of the bottom plugs......Cliff

damoroso:
Thanks Cliff, I'll bump the pressure up, I'll also order the larger inlet seat anyway, just to be sure.  As for the fuel at the EGR vacuum fitting, it's not leaking out of there, it's just when I pull the plug off, (was checking vacuum) it's wet with fuel and I find that odd.  And that would indicate to me that there could be fuel getting into the intake that's not coming through the primairies.  I've had the carb off and there's no fuel in the manifold when it sits overnight, so I'm really at a loss to explain this.  I csan live with it, but I don't think this should be happening...thanks again for the help!

Cliff Ruggles:
Not a problem, let me know how it works.

I use a .145" seat in my carb, and it easily supports nearly 600hp with a sumped tank and 8AN lines everyplace, electric 140gph pump behind the tank.....Cliff

damoroso:
Okay, I went to the .149" seat, brought the pressure to 6.5-7psi and the problem is better, but it's still there just enough to be frustrating.  I'm running the stock fuel line to the pump, and 6AN lines to the carb.  Maybe I should replace it all with 8AN?  My other thought is maybe the fuel bowl in the E4ME carb is smaller than the others?  If that's the case, I can see areas that could be opened up a bit with a dremel, that might help, but I'd think 140gph should be able to keep up regardless.  Hell, maybe my estimated 550HP is low! LOL

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