Quadrajet Help! - Page 2 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

79gmcc15 · 10-10-2009, 10:48 PM

well, one thing you could do is take the line off and turn the motor till it pumps some out. it does not need a lot of PSI to run the motor, like 5 PSI. so don't be surprised if it does not come out like crazy. maybe have a cup ready so you don't spill it everywhere. that might make it easier to start knowing the gas has made it from the tank to the tube. just be patient with it, don't crank and crank and crank. go like 10 seconds then stop for 5 to keep from getting the starter hot.

GMC Guy · 10-10-2009, 10:53 PM

ok thanks i'll give that a shot

GMC Guy · 10-11-2009, 12:00 AM

ok, so i am getting fuel to the line, and hopefully into the carb. but it still won't turn over on it's own, only when i pour a little gas into it.

79gmcc15 · 10-11-2009, 12:34 AM

next step would be to look down the carb to see if it is squirting fuel in. if it is, then you need to check for spark problems. if it is not then something is up with the carb.

GMC Guy · 10-11-2009, 12:38 AM

well it ran when i took it off earlier this week, but i'll check tomorrow if its squirting fuel.

cowboy5683 · 10-11-2009, 07:00 AM

Yes yer fuel pump could be bad..but u said earlier u had fuel at that point..kinda wierd..follow the other steps I lined out and see where yer at from there.lemme know what happens..If you need personal help my cell is 951 - 385 -3512..I may not answer right away but leave message and I will call back asap n help u if I can.

cowboy5683 · 10-11-2009, 07:09 AM

Looking at the other replies it looks like yer goin in the right direction..except it couldnt b spark if it runs when ya pour gas down the vent n it starts..gotta be a fuel problem that is not allowing it to get into the bowl and then continuing to come in n allowing it to run..15/32" is right for that carb..call me n if I dont answer I will call you back n try to help you A.S.A.P.

GMC Guy · 10-11-2009, 04:53 PM

ok, so i pulled the carb back off today, and took it apart. the bowl was completely dry. so somehow fuel is not filling in the bowl. while i had it off i filled the bowl with fuel, and the float rose how it should. the needle and seat are also new. so after filling it with a little gas, i put it back on and it only fired the gas that was in there, then nothing....soo for some reason the carb is not filling with gas, even though it has fuel pressure going into it...
Any Suggestions are greatly appreciated.

ron350 · 10-11-2009, 05:08 PM

Did you check to make sure the fuel filter is not in backwards?

GMC Guy · 10-11-2009, 05:10 PM

haha yes i did...

billnorman · 10-11-2009, 05:49 PM

This site helped me a lot. It may help you. http://dyeager535.topcities.com/CCCqjetdiagram.html

GMC Guy · 10-11-2009, 06:02 PM

thanks, that is a helpful diagram

Rogue_Sentinel · 10-11-2009, 07:52 PM

sorry 2 hi jack your thread,

but does it really cost $400 to have the Quadrajet rebuilt ? i was going to have my rebuilt, by someone that has done it be for. i did good just to get it off the intake .

cowboy5683 · 10-11-2009, 07:59 PM

Looking at whats been posted and what you said there has to be some kind of blockage inside the carb from the inlet(mebbe the filter?) or within the needle and seat..either from bein stuck shut somehow or debris lodged in the passageway some how..Seems to me thats the only things it could be...As far as a 400 dollar rebuild..yes it can cost that much..but it all depends on the shop and exactly how much work that shop is doing i.e. unwarping body and airhorn, replacing bushings etc..thats when it starts to get pricey.

79gmcc15 · 10-11-2009, 08:13 PM

Cowboy was right about what I said on the spark lol I forgot that it ran. and he is right about what he just said. if you have a rubber line from the pump to the carb*or anywhere really* you can get a cheep fuel filter and put that on and take out the one in the carb just to rule out one thing. or you might be able to get a way with out running the filter for testing reasons. but you do risk having crap get in there. you can take off the top again and find out were the fuel gets dumped into the bowl and spray a bunch of carb cleaner in there to flush it out.

GMC Guy · 10-11-2009, 08:20 PM

while i had the carb off today, i poured gas down the seat, and it came out the filter inlet. so i know it's clear from that point. then i tested the float by filling the bowl with gas. i know this sounds bad, but should i change the needle and seat back to the original one? it couldn't hurt i guess...otherwise i'm very close to forking over the money for a new carb.

which brings me to another question. what cfm is recommended for a 350? i've been looking at the edelbrock 600, 650, and 750. i really want the higher cfm, but would the 750 be too much? keep in mind, that eventually i want to build the motor for more performance.

donut · 10-11-2009, 11:44 PM

When you put the filter in did you use teflon tape on the threads?
If you did, it's possible there is a piece acting as a "flapper" on the inlet. Kinda like a check valve.

Do the needle and float move freely? Is it possible something is binding and jamming the needle onto the seat? If you've got gas to the carb, and you get flow through, it's all I can think of.

Rogue_Sentinel · 10-11-2009, 11:54 PM

http://www.spike.com/full-episode/qu...-rebuild/33035

they make it look e z

GMC Guy · 10-12-2009, 01:06 AM

Quote:

Originally Posted by Rogue_Sentinel

http://www.spike.com/full-episode/qu...-rebuild/33035

they make it look e z

oh i know, i've watched that video 100 times. but also, they don't show it running after they're done

GMC Guy · 10-12-2009, 01:11 AM

Quote:

Originally Posted by donut

When you put the filter in did you use teflon tape on the threads?
If you did, it's possible there is a piece acting as a "flapper" on the inlet. Kinda like a check valve.

Do the needle and float move freely? Is it possible something is binding and jamming the needle onto the seat? If you've got gas to the carb, and you get flow through, it's all I can think of.

i did put teflon tape on the threads of the fuel line. but i made sure it wasn't over the edge. but i'll have to check the needle and seat tomorrow. might have to put the old needle back in, at least i know it worked....

cowboy5683 · 10-12-2009, 01:12 AM

Nice video..I would take tha filter out for testing purposes and see if it is restricting fuel in any way..the little back flow checkvalve in the fule filter itself could be stuck also..mebbe take a phillips head driver and push on it to make sure it isnt stuck closed and mebbe thats it..I would not put the old seat in unless you have a new metal gasket under it for leak reasons..sounds like its gonna be sumthing really dumb and obvious and yer gonna wanna hang yerself when ya see it..I have done that to myself a 1000 x's..lol..that particular carb is a great carb when set up right..great fuel economy when ya can keep yer foot out of it cus of the small primaries..and will flow 750cfm to 850cfm when wide open cus of the huge secondaries..i would try to fix what ya got..you are waaay too close...and when it runs good you will love it!!

cowboy5683 · 10-12-2009, 01:14 AM

I personally have never used teflon on the fuel inlet threads..no need if the clear plastic ring is in place right..gas will eat teflon tape for breakfast and wreak havoc in the little places it can get stuck in a quadrajet.

dga93 · 10-12-2009, 01:15 AM

My friend and I rebuilt my carb and when we did he lost the spring and clips. but i was lucky to have a kids hands to look and find them. maybe the spring isnt there or something? and/or check the hole where the gas should be coming in.. maybe there could be something inside stopping it. i used cue tips on mine and some got stuck a little. i hope you get it fixed.

GMC Guy · 10-12-2009, 01:16 AM

thanks for the encouraging words haha tomorrow i will definitely try running it without a filter and maybe remove the teflon, or basically try anything lol

GMC Guy · 10-12-2009, 01:48 AM

ok i couldn't wait til tomorrow so i just tried running it without the filter. no success still. but even when i pulled the filter inlet out after trying it, it was completely dry, not even a drip of fuel came out of the line or the carb...

really scratching my head now...

10-10-2009, 10:48 PM	#26
79gmcc15 Gettin It One Pice At A Time Join Date: Oct 2004 Location: everett, washington Posts: 2,688	Re: Quadrajet Help! well, one thing you could do is take the line off and turn the motor till it pumps some out. it does not need a lot of PSI to run the motor, like 5 PSI. so don't be surprised if it does not come out like crazy. maybe have a cup ready so you don't spill it everywhere. that might make it easier to start knowing the gas has made it from the tank to the tube. just be patient with it, don't crank and crank and crank. go like 10 seconds then stop for 5 to keep from getting the starter hot. __________________ RIP ELJAY Work In Progress 1979 GMC C1500 Trailering Special. Getting the truck done, one piece at a time. “You can tell a lot about a fellow’s character by his way of eating jellybeans.”Ronald Reagan “I don’t know the key to success but I know the key to failure is trying to please everybody.” Bill Cosby Last edited by 79gmcc15; 10-10-2009 at 10:50 PM.

10-10-2009, 10:53 PM	#27
GMC Guy Registered User Join Date: May 2009 Location: Sparks, NV Posts: 913	Re: Quadrajet Help! ok thanks i'll give that a shot __________________ Greg 1974 GMC 1/2 Ton SWB Fleetside L33 5.3/4l65e .................__ ............._____l __\__ ..............l_(O)_ l___(O)]

10-11-2009, 12:00 AM	#28
GMC Guy Registered User Join Date: May 2009 Location: Sparks, NV Posts: 913	Re: Quadrajet Help! ok, so i am getting fuel to the line, and hopefully into the carb. but it still won't turn over on it's own, only when i pour a little gas into it. __________________ Greg 1974 GMC 1/2 Ton SWB Fleetside L33 5.3/4l65e .................__ ............._____l __\__ ..............l_(O)_ l___(O)]

10-11-2009, 12:34 AM	#29
79gmcc15 Gettin It One Pice At A Time Join Date: Oct 2004 Location: everett, washington Posts: 2,688	Re: Quadrajet Help! next step would be to look down the carb to see if it is squirting fuel in. if it is, then you need to check for spark problems. if it is not then something is up with the carb. __________________ RIP ELJAY Work In Progress 1979 GMC C1500 Trailering Special. Getting the truck done, one piece at a time. “You can tell a lot about a fellow’s character by his way of eating jellybeans.”Ronald Reagan “I don’t know the key to success but I know the key to failure is trying to please everybody.” Bill Cosby

10-11-2009, 12:38 AM	#30
GMC Guy Registered User Join Date: May 2009 Location: Sparks, NV Posts: 913	Re: Quadrajet Help! well it ran when i took it off earlier this week, but i'll check tomorrow if its squirting fuel. __________________ Greg 1974 GMC 1/2 Ton SWB Fleetside L33 5.3/4l65e .................__ ............._____l __\__ ..............l_(O)_ l___(O)]

10-11-2009, 07:00 AM	#31
cowboy5683 Registered User Join Date: Jun 2009 Location: San Bernardino CA Posts: 94	Re: Quadrajet Help! Yes yer fuel pump could be bad..but u said earlier u had fuel at that point..kinda wierd..follow the other steps I lined out and see where yer at from there.lemme know what happens..If you need personal help my cell is 951 - 385 -3512..I may not answer right away but leave message and I will call back asap n help u if I can.

10-11-2009, 07:09 AM	#32
cowboy5683 Registered User Join Date: Jun 2009 Location: San Bernardino CA Posts: 94	Re: Quadrajet Help! Looking at the other replies it looks like yer goin in the right direction..except it couldnt b spark if it runs when ya pour gas down the vent n it starts..gotta be a fuel problem that is not allowing it to get into the bowl and then continuing to come in n allowing it to run..15/32" is right for that carb..call me n if I dont answer I will call you back n try to help you A.S.A.P.

10-11-2009, 04:53 PM	#33
GMC Guy Registered User Join Date: May 2009 Location: Sparks, NV Posts: 913	Re: Quadrajet Help! ok, so i pulled the carb back off today, and took it apart. the bowl was completely dry. so somehow fuel is not filling in the bowl. while i had it off i filled the bowl with fuel, and the float rose how it should. the needle and seat are also new. so after filling it with a little gas, i put it back on and it only fired the gas that was in there, then nothing....soo for some reason the carb is not filling with gas, even though it has fuel pressure going into it... Any Suggestions are greatly appreciated. __________________ Greg 1974 GMC 1/2 Ton SWB Fleetside L33 5.3/4l65e .................__ ............._____l __\__ ..............l_(O)_ l___(O)]

10-11-2009, 05:08 PM	#34
ron350 Registered User Join Date: Apr 2007 Location: Birmingham AL Posts: 254	Re: Quadrajet Help! Did you check to make sure the fuel filter is not in backwards? __________________ Stock 75 C10 step side. 350 2 BBL, 350 trans. 150K miles.

10-11-2009, 05:10 PM	#35
GMC Guy Registered User Join Date: May 2009 Location: Sparks, NV Posts: 913	Re: Quadrajet Help! haha yes i did... __________________ Greg 1974 GMC 1/2 Ton SWB Fleetside L33 5.3/4l65e .................__ ............._____l __\__ ..............l_(O)_ l___(O)]

10-11-2009, 05:49 PM	#36
billnorman Registered User Join Date: Mar 2009 Location: glen burnie md Posts: 174	Re: Quadrajet Help! This site helped me a lot. It may help you. http://dyeager535.topcities.com/CCCqjetdiagram.html

10-11-2009, 06:02 PM	#37
GMC Guy Registered User Join Date: May 2009 Location: Sparks, NV Posts: 913	Re: Quadrajet Help! thanks, that is a helpful diagram __________________ Greg 1974 GMC 1/2 Ton SWB Fleetside L33 5.3/4l65e .................__ ............._____l __\__ ..............l_(O)_ l___(O)]

10-11-2009, 07:52 PM	#38
Rogue_Sentinel Registered User Join Date: Mar 2009 Location: nc, mount airy Posts: 376	Re: Quadrajet Help! sorry 2 hi jack your thread, but does it really cost $400 to have the Quadrajet rebuilt ? i was going to have my rebuilt, by someone that has done it be for. i did good just to get it off the intake . __________________ "Myths and legends die hard in America. We love them for the extra dimension they provide, the illusion of near-infinite possibility to erase the narrow confines of most men's reality. Weird heroes and mould-breaking champions exist as living proof to those who need it that the tyranny of 'the rat race' is not yet final." Hunter S THompson

10-11-2009, 07:59 PM	#39
cowboy5683 Registered User Join Date: Jun 2009 Location: San Bernardino CA Posts: 94	Re: Quadrajet Help! Looking at whats been posted and what you said there has to be some kind of blockage inside the carb from the inlet(mebbe the filter?) or within the needle and seat..either from bein stuck shut somehow or debris lodged in the passageway some how..Seems to me thats the only things it could be...As far as a 400 dollar rebuild..yes it can cost that much..but it all depends on the shop and exactly how much work that shop is doing i.e. unwarping body and airhorn, replacing bushings etc..thats when it starts to get pricey.

10-11-2009, 08:13 PM	#40
79gmcc15 Gettin It One Pice At A Time Join Date: Oct 2004 Location: everett, washington Posts: 2,688	Re: Quadrajet Help! Cowboy was right about what I said on the spark lol I forgot that it ran. and he is right about what he just said. if you have a rubber line from the pump to the carbor anywhere really you can get a cheep fuel filter and put that on and take out the one in the carb just to rule out one thing. or you might be able to get a way with out running the filter for testing reasons. but you do risk having crap get in there. you can take off the top again and find out were the fuel gets dumped into the bowl and spray a bunch of carb cleaner in there to flush it out. __________________ RIP ELJAY Work In Progress 1979 GMC C1500 Trailering Special. Getting the truck done, one piece at a time. “You can tell a lot about a fellow’s character by his way of eating jellybeans.”Ronald Reagan “I don’t know the key to success but I know the key to failure is trying to please everybody.” Bill Cosby



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10-11-2009, 08:20 PM	#41
GMC Guy Registered User Join Date: May 2009 Location: Sparks, NV Posts: 913	Re: Quadrajet Help! while i had the carb off today, i poured gas down the seat, and it came out the filter inlet. so i know it's clear from that point. then i tested the float by filling the bowl with gas. i know this sounds bad, but should i change the needle and seat back to the original one? it couldn't hurt i guess...otherwise i'm very close to forking over the money for a new carb. which brings me to another question. what cfm is recommended for a 350? i've been looking at the edelbrock 600, 650, and 750. i really want the higher cfm, but would the 750 be too much? keep in mind, that eventually i want to build the motor for more performance. __________________ Greg 1974 GMC 1/2 Ton SWB Fleetside L33 5.3/4l65e .................__ ............._____l __\__ ..............l_(O)_ l___(O)]

10-11-2009, 11:44 PM	#42
donut Registered User Join Date: Aug 2009 Location: S.C. Posts: 1,593	Re: Quadrajet Help! When you put the filter in did you use teflon tape on the threads? If you did, it's possible there is a piece acting as a "flapper" on the inlet. Kinda like a check valve. Do the needle and float move freely? Is it possible something is binding and jamming the needle onto the seat? If you've got gas to the carb, and you get flow through, it's all I can think of. __________________ '86 C-30 dually, 454/tbh400 '73 K-20 350/350/205 (sold ) I'm kinda like duct tape- no real purpose, but handy to have around.

10-11-2009, 11:54 PM	#43
Rogue_Sentinel Registered User Join Date: Mar 2009 Location: nc, mount airy Posts: 376	Re: Quadrajet Help! http://www.spike.com/full-episode/qu...-rebuild/33035 they make it look e z __________________ "Myths and legends die hard in America. We love them for the extra dimension they provide, the illusion of near-infinite possibility to erase the narrow confines of most men's reality. Weird heroes and mould-breaking champions exist as living proof to those who need it that the tyranny of 'the rat race' is not yet final." Hunter S THompson

10-12-2009, 01:12 AM	#46
cowboy5683 Registered User Join Date: Jun 2009 Location: San Bernardino CA Posts: 94	Re: Quadrajet Help! Nice video..I would take tha filter out for testing purposes and see if it is restricting fuel in any way..the little back flow checkvalve in the fule filter itself could be stuck also..mebbe take a phillips head driver and push on it to make sure it isnt stuck closed and mebbe thats it..I would not put the old seat in unless you have a new metal gasket under it for leak reasons..sounds like its gonna be sumthing really dumb and obvious and yer gonna wanna hang yerself when ya see it..I have done that to myself a 1000 x's..lol..that particular carb is a great carb when set up right..great fuel economy when ya can keep yer foot out of it cus of the small primaries..and will flow 750cfm to 850cfm when wide open cus of the huge secondaries..i would try to fix what ya got..you are waaay too close...and when it runs good you will love it!!

10-12-2009, 01:14 AM	#47
cowboy5683 Registered User Join Date: Jun 2009 Location: San Bernardino CA Posts: 94	Re: Quadrajet Help! I personally have never used teflon on the fuel inlet threads..no need if the clear plastic ring is in place right..gas will eat teflon tape for breakfast and wreak havoc in the little places it can get stuck in a quadrajet.

10-12-2009, 01:15 AM	#48
dga93 newbie Join Date: Feb 2009 Location: Wise Virginia Posts: 122	Re: Quadrajet Help! My friend and I rebuilt my carb and when we did he lost the spring and clips. but i was lucky to have a kids hands to look and find them. maybe the spring isnt there or something? and/or check the hole where the gas should be coming in.. maybe there could be something inside stopping it. i used cue tips on mine and some got stuck a little. i hope you get it fixed. __________________ Daniel from AUS 1978 CD

10-12-2009, 01:16 AM	#49
GMC Guy Registered User Join Date: May 2009 Location: Sparks, NV Posts: 913	Re: Quadrajet Help! thanks for the encouraging words haha tomorrow i will definitely try running it without a filter and maybe remove the teflon, or basically try anything lol __________________ Greg 1974 GMC 1/2 Ton SWB Fleetside L33 5.3/4l65e .................__ ............._____l __\__ ..............l_(O)_ l___(O)]

10-12-2009, 01:48 AM	#50
GMC Guy Registered User Join Date: May 2009 Location: Sparks, NV Posts: 913	Re: Quadrajet Help! ok i couldn't wait til tomorrow so i just tried running it without the filter. no success still. but even when i pulled the filter inlet out after trying it, it was completely dry, not even a drip of fuel came out of the line or the carb... really scratching my head now... __________________ Greg 1974 GMC 1/2 Ton SWB Fleetside L33 5.3/4l65e .................__ ............._____l __\__ ..............l_(O)_ l___(O)]

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