quadrajet problem

rjarrell · 03-29-2010, 03:21 PM

quadrajet loading fuel on idle
adjusting air and fuel does not make any differance.
newly rebuilt carb
new fuel pump
new gas line feed and return to tank
new gas tank
350 chevy rebuilt , fresh start
any ideas?

Chipper Chapman · 03-29-2010, 03:33 PM

May seem stupid, but i've done it so i'll ask, If the carb has been rebuilt, are you sure you have the correct body to top gasket? In some apps some are very close to right, but not right. Had one with the same symptons and thats what turned out to be. Also, the float could be too high, needle/seat stuck open or out of place

raceewing · 03-29-2010, 03:36 PM

I just had the same problem on my thermoquad, had a bad float.

rjarrell · 03-29-2010, 03:51 PM

did not rebuild carb myself
was sent to the Toronto area, to a company that rebuilds carbs.
Just making sure i cover all bases before i send it back.
I have also been told it could be a low vacuum problem, or a
fuel pressure prob. will check it out first. Thank's for the help.

Mike Savelle · 03-29-2010, 04:07 PM

had the same problem . replace the float with a new one

Bob Pagano · 03-29-2010, 04:28 PM

Check fuel pressure, some will piss by with over 6-7 lbs

GTX JOHN · 03-30-2010, 12:12 PM

If you are going to race your car, the carb requires a fair amount of specialized mods. You didn't say if you used a generic rebuilder or race specialist. It could certainly be a simple fix as suggested and probably is.....I have found it a really challenge to make Stock/SS car idle (low vacume/lots of overlap in cam). Danny Ashley is the one that I recommend to rework one....very approachable and patient with me: #1 in my book!

tj310 · 03-31-2010, 11:00 AM

Everybody has their stories. I have found that a pure stock Quadrajet may work fine on a 10 sec superstocker...Thanx Trevor

Marvin Robinson · 04-09-2010, 10:52 AM

In addition to the above, Check & make sure the that the top gasket is not binding the power valve needles - there is a slot in the gasket that the hanger has to go thru, and it can easily get caught on the power valve body when you install the top lid of the carb if you're not careful. Also, check for leaking at the fuel well plugs at the bottom. Sometimes they will leak when subjected to the carb cleaning solutions used, and most good rebuilders will seal the bottom of the well with epoxy, pipe plug, etc. Both of these conditions could cause unmetered fuel to drip or flow into the manifold, and render the adjustment needles unresponsive.

Dragsinger · 04-09-2010, 12:19 PM

JT310,

I agree with your statement, however, there are some specific mods that help the drag race Q-jet. Experienced builders like Danny Ashley and Bubba Oliver know the "little" things that do make a difference. In some cases the difference is not much, in other cases the difference is enough to matter.

03-29-2010, 03:33 PM	#2
Chipper Chapman Member Join Date: Jan 2004 Location: Belmont N.S. Canada Posts: 473 Likes: 246 Liked 166 Times in 71 Posts	Re: quadrajet problem May seem stupid, but i've done it so i'll ask, If the carb has been rebuilt, are you sure you have the correct body to top gasket? In some apps some are very close to right, but not right. Had one with the same symptons and thats what turned out to be. Also, the float could be too high, needle/seat stuck open or out of place

03-29-2010, 03:36 PM	#3
raceewing Junior Member Join Date: May 2006 Location: usa Posts: 24 Likes: 0 Liked 0 Times in 0 Posts	Re: quadrajet problem I just had the same problem on my thermoquad, had a bad float.

03-29-2010, 03:51 PM	#4
rjarrell Junior Member Join Date: Mar 2010 Posts: 2 Likes: 0 Liked 0 Times in 0 Posts	Re: quadrajet problem did not rebuild carb myself was sent to the Toronto area, to a company that rebuilds carbs. Just making sure i cover all bases before i send it back. I have also been told it could be a low vacuum problem, or a fuel pressure prob. will check it out first. Thank's for the help. Last edited by rjarrell; 03-29-2010 at 03:55 PM.

03-29-2010, 04:07 PM	#5
Mike Savelle Member Join Date: Dec 2001 Location: Ontario Canada Posts: 369 Likes: 125 Liked 7 Times in 5 Posts	Re: quadrajet problem had the same problem . replace the float with a new one

03-29-2010, 04:28 PM	#6
Bob Pagano VIP Member Join Date: Jun 2002 Location: New Holland, PA Mooresville,NC Posts: 1,163 Likes: 239 Liked 16 Times in 11 Posts	Re: quadrajet problem Check fuel pressure, some will piss by with over 6-7 lbs __________________ Bob Pagano A/SA

03-29-2010, 03:21 PM	#1
rjarrell Junior Member Join Date: Mar 2010 Posts: 2 Likes: 0 Liked 0 Times in 0 Posts	quadrajet problem quadrajet loading fuel on idle adjusting air and fuel does not make any differance. newly rebuilt carb new fuel pump new gas line feed and return to tank new gas tank 350 chevy rebuilt , fresh start any ideas?

03-30-2010, 12:12 PM	#7
GTX JOHN VIP Member Join Date: Jun 2009 Location: Boulder City, Nevada 89005 Posts: 2,731 Likes: 2,794 Liked 2,471 Times in 696 Posts	Re: quadrajet problem If you are going to race your car, the carb requires a fair amount of specialized mods. You didn't say if you used a generic rebuilder or race specialist. It could certainly be a simple fix as suggested and probably is.....I have found it a really challenge to make Stock/SS car idle (low vacume/lots of overlap in cam). Danny Ashley is the one that I recommend to rework one....very approachable and patient with me: #1 in my book!

03-31-2010, 11:00 AM	#8
tj310 Member Join Date: Sep 2009 Location: Dresden On. Canada Posts: 460 Likes: 0 Liked 0 Times in 0 Posts	Re: quadrajet problem Everybody has their stories. I have found that a pure stock Quadrajet may work fine on a 10 sec superstocker...Thanx Trevor

04-09-2010, 10:52 AM	#9
Marvin Robinson Member Join Date: Jun 2005 Location: Gary, IN Posts: 139 Likes: 0 Liked 0 Times in 0 Posts	Re: quadrajet problem In addition to the above, Check & make sure the that the top gasket is not binding the power valve needles - there is a slot in the gasket that the hanger has to go thru, and it can easily get caught on the power valve body when you install the top lid of the carb if you're not careful. Also, check for leaking at the fuel well plugs at the bottom. Sometimes they will leak when subjected to the carb cleaning solutions used, and most good rebuilders will seal the bottom of the well with epoxy, pipe plug, etc. Both of these conditions could cause unmetered fuel to drip or flow into the manifold, and render the adjustment needles unresponsive. __________________ Marvin Robinson 3188 STK/SS Last edited by Marvin Robinson; 04-09-2010 at 11:18 AM.

04-09-2010, 12:19 PM	#10
Dragsinger VIP Member Join Date: Jul 2008 Location: Liberty City [East Texas] Posts: 1,760 Likes: 5 Liked 99 Times in 60 Posts	Re: quadrajet problem JT310, I agree with your statement, however, there are some specific mods that help the drag race Q-jet. Experienced builders like Danny Ashley and Bubba Oliver know the "little" things that do make a difference. In some cases the difference is not much, in other cases the difference is enough to matter. __________________ Larry Woodfin 471W