When i punch it....it hesitates b4 take-off
When i punch it....it hesitates b4 take-off
What would the problem be if when i punch it, it waits 3 seconds then it goes? 4 barrel 305 86 TA
Last edited by Makai; Aug 19, 2002 at 12:42 PM.
Joined: Mar 2000
Posts: 43,187
Likes: 42
From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
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.
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.
Member
Joined: Jul 2002
Posts: 191
Likes: 0
From: Miami, Florida
Car: Camaro Z28
Engine: 350
Transmission: auto
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
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Joined: Mar 2000
Posts: 43,187
Likes: 42
From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Originally posted by 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
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
Originally posted by five7kid
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.
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.
Originally posted by five7kid
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.
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.
Supreme Member
Joined: Mar 2002
Posts: 4,812
Likes: 0
From: 62656
Car: 1991 S10 pickup 2700lbs
Engine: 4.3L Z TBI
Transmission: 700R4
Axle/Gears: 3.08 7.625"
Originally posted by five7kid
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.
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.
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
Supreme Member
Joined: Mar 2002
Posts: 4,812
Likes: 0
From: 62656
Car: 1991 S10 pickup 2700lbs
Engine: 4.3L Z TBI
Transmission: 700R4
Axle/Gears: 3.08 7.625"
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!
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!
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