Quadrajet Problem Solving > Dialing in your rebuilt Quadrajet carburetor

slight hesitation off idle

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Cliff Ruggles:
When the engine is suddenly asked to work, vacuum falls off sharply.  This causes the power piston to raise up as spring tension overcomes the vacuum signal to it.  APT adjustment would have no effect here.

I would make sure that the metering rods are correctly located in the jets, and well up on the small tips of the rods at full lift.

The height of the metering rods (secondary hanger) and which metering rods are being used will have a big impact on fuel delivery when the secondaries are brought on quickly.

The accellator pump plays a role here, but it appears from your description that it is working correctly.

Seconary POE is another player in that system as well.......Cliff

Marx3:
I will check up on the rod-location!

regarding acc-pump.. it seems to be working exactly like it should, I dont remember the size of the shot-holes, but it was built as close to recipe 2 as possible. And thing is... if you step on the throttle two times when flooring it, the hesitation disappears, and the engine just pulls freely.

POE restr. are .058

should I go up or down on hanger height and sec. rod size? and slower or faster on the pull-off? Just to have guidelines you know...

Marx3:
Hmm, putting in a 2200 stall converter seems to have practically eliminated the problem...
new problem: it runs out of gas at some point in 3 gear :-) time to do something about the stock fuelpump :-)

We are getting the engine dyno'd next week, and I just can't wait to see the results!!! Especially in the fuelratio department! I will post the results!

Marx3:
power as measured at the wheels: 257 hp / 390 ft.lbs. AF-ratio was 13.6 at 60 mph, and 12.7 at wot.
tried installing 52 rods, but that bumped AF-ratio to 14.9/15 at cruise, so we stayed with the 50's.
So all in all, great succes!

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