Makai

What would the problem be if when i punch it, it waits 3 seconds then it goes? 4 barrel 305 86 TA

Fast3rdGen

what kind of carb/jetting/metering are you running? sounds to me like lean stumble but not enough info to tell.

Makai

4 barrel 305 86 TA

five7kid

iTrader: (14)

Sounds like classic q-jet bog.

There's a tech article that goes through what you need to do to get it tuned (https://www.thirdgen.org/newdesign/tech/quadrajet.shtml). Check it out.

Vettetrax

actually it might be the mechanical fuel pump i had the same prob with my q-jet, i now have a edlebrock 600cfm 4barrel and i have the same prob, i just think that the mechanical fuel pump takes time to suck the fuel from tank then push it to the carb thats all

BAK12484

same problem on my 350 TPI. It doesn't quite hesitate for 3 seconds, but a for a second or so...not too sure what it is either

Makai

NOTE: I'm guestimating when i say 3 seconds. Could be less

five7kid

iTrader: (14)

No way. The pump should keep the fuel bowl full at all times. If it bogged as soon as you nailed it and the fuel pump was to blame, the problem would get worse, not better, after the initial hesitation.

Makai

So what would be the remedy for this particular problem?

Makai

Hey, thanx for this link, it's looks pretty easy. I hope i can figure it out

Randy82WS7

yep, the bowl always has fuel in it, unles you have a major float or needle and seat problem in there, but then you would have higher rpm bog/cut out problem then.. wouldnt even be able to cruise at say 40mph or so or faster and woud kinda cut out misfire sorta when trying to get it going faster...

i have this same split second cutout bog when taking off from dead stop in the 84 Z28 LG4..
il probably eventualy swap on an old model rebuilt q jet. already have a 75-79 HEI on it,. that alone increased performance noticeably, also new fuel pump recently





good luck

Randy82WS7

https://www.thirdgen.org/newdesign/tech/quadrajet.shtml
update:
a coule hours ago i went and did the carb AV adjustment to my 84 Z28, and also noticed that all the airhorn attaching screws were loose, so i tightened them all down snug, my carb is one of those uncommon torx screw models- as noted on that page- so i guiess its special or whatever, more like a pain in the *** really,
used the smallest torx bit on the rack to loosen and retighten the lockscrew up under the airhorn lip, had to use tiny pen flathead screwdriver to turn the AV shaft spring adjusting screw,

my secondary air valves dont have hardly any resistance to opening at all, very super easy to open, seems like now dont have as much split second off idle stumble now, especially with hood off and air cleaner assembly off, also engine is running about 20 degrees cooler too and probably weighs alot less without the hood. i found out recently that my air damn is missing from under car.....

also while i was underhood( actually i went al the way and removed the hood for now) i found that my MAP sensor was not connected t a vacuum sourc,e the hose was not even in existance, so i got one for it to connect to manifold vacuum port on the base of RH side of carb,and also replaced the 3/8" charcoal canister to fuel bowl vent port hose, it was rotted badly.
also connected vacuum guage to intake vacuum source and made sure it was 18-22hg., and it was, after advancing initial timing a ittle more, now my idle is a little fast, but i have no diesleing problem at shutdown, so all is good cept when i put car in gear it chirps, hehe, need ot knock off about 150 or so RPM off the idle.
i have a 454 truck coming soon, since car wont sell no one seems ot want it, im thinking about 454 install and rail the car til its breaks, is a t tops car, so,,, hmmmm...

hope some of this info helps someone in some way,

good luck!