Quadrajet Problem Solving > Diagnose a Quadrajet carburetor problem

lean spot when coming into the secondaries

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Marx3:
Same car / engine / carb as in my other thread.
When driving around with my wideband hooked up, I noticed that the AFR goes rich as it should ( about 12.5:1 ) once I get into the secondaries, but leans out a bit ( about 13.5:1 ) for a second and then returns to a safer richer ratio.
I am running stock CP needles afair,. raised the hanger a bit to hit 12.5:1. but why do I get this moment of semi-lean afr, once the secondaries have opened?

Are the butterflies bouncing maybe?
It is not something that can be felt at all. just shows on the wideband. 13.5:1 is too lean for my liking in a 10:1 iron headed engine

Cliff Ruggles:
You may be seeing the secondary POE wells being sucked low or dry......Cliff

Marx3:
The holes are at .040 as always...
Would it be bad to go to .042 or so?

Cliff Ruggles:
Not sure, I try to keep them smaller so they don't continue to add fuel and make things too rich.  There is no other reason to be seeing a momentary lean spot unless the bowl is going low for a second, then filling back up and recovering to the richer A/F ratio.

I'd certainly address fuel delivery before opening up the POE holes.....Cliff

Marx3:
I can hold it at wot forever.  ( on an empty freeway for instance )
Don't think anything is wrong with the fuel delivery?
Once it goes wot and rpm climb, it tends to ping a bit, but only at "higher" rpm.

Wait, which holes are you referring to when you say poe... The ones in the bowl, the ones at the bottom end of the tubes or the hole up above the air flaps?

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