Quadrajet running super rich.

[Chillin014]

I'm pretty frustrated with carburetors right about now. I spent almost 300 bucks on a 750 cfm rebuilt Quadrajet a year or so ago in hopes of getting better gas mileage and the thing has been nothing but a pain to deal with. I finally hooked up my wideband o2 sensor to get a reading because I knew it was running rich and sure enough I'm at about 9:1 during idle and 10:1 during driving on average. Is this normal for a carbureted set-up? I was tweaking with the idle screws and the reading jumps all over the place.

Not to mention the top gasket on the carb has been gas soaked from day-1. I'm getting about 10 mpg with a 400ci sbc and a 5 speed.

Are these air/fuel ratio readings normal? Any advice is appreciated...I really would love to ditch this junk for EFI but I don't think I can afford it.

 

[DOUG213XRJ]

I would set by resetting the floot level. That just might clear everything up. Doug

 

[t5montecarlo]

If you have a plastic float, replace it with a brass float. The plastic ones can take on fuel and sink.

 

[LS6 Tommy]

X2 on both of the above. Unfortunately, every stock "rebuilt" Quad I've ever had experience with required a proper going through. None of them ever seem to be done right.

Tommy

 

[StreetBu]

I had the same issues with mine and dealt with it for years. I was so unhappy. Finally lost my patients and sent my Quadrajet to SMI (Sean Murphy Induction) I had already bought a carb kit so that went with it. He rebuilt it, bushed the throttle shaft that was loose and did the stage 2 mods along with epoxying the welch plugs in the base. My car has NEVER run so good and got this mileage. Well worht the $250 he charged me. I did have to buy the tool to adjust the idle screws as he says you MUST do it when it's bolted back on. I tried not doing it but it wasnt any better, once I adjusted them it was perfect. He asks for ALOT of info from you so he can tune it right with the rods and hangers. Cam timing, lift, duration, axle ratio, transmission type, intended usage, etc.