Fuel pump/flooding/psi? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

jdurant · 07-19-2009, 08:50 PM

Friday I started smelling gas. Noticed a little trickle of fuel coming from the fuel pump where the two halves meet. So, I installed a new fuel pump--stock replacement for my stock 305 with new quadrajet. Now with the new fuel pump, the truck will barely start. It floods. I teed a pressure guage in the fuel line and it reads 8-0-8-0-8-0-8-0.
I think it should read like 4, right? And that is a constant 4 right?

powerdriver 1958 · 07-19-2009, 10:09 PM

would think it would be closer to 6 lbs,Is there a chance that some dirt may have gotten through to the carb?

jdurant · 07-20-2009, 09:53 AM

Yes, there is a very good chance of that. It's a long story, but I thought I was over that problem, and had run enough fuel and carb cleaner through it.

It was running fine before I changed the fuel pump. Could this new fuel pump with the 8-0-8-0-8-0-8-0 psi be causing it to flood out. When you look at the guage, it should be constant, huh?

powerdriver 1958 · 07-20-2009, 06:31 PM

What brand pump?There is a thread running with almost the same problem for cheap imported fuel pumps.

http://67-72chevytrucks.com/vboard/s...d.php?t=353676

jdurant · 07-20-2009, 11:05 PM

Quote:

Originally Posted by powerdriver 1958

What brand pump?There is a thread running with almost the same problem for cheap imported fuel pumps.

http://67-72chevytrucks.com/vboard/s...d.php?t=353676

It is a besttest from o'reilly.

I have read Poke's thread. It really doesn't help me much.

What should the fuel pressure be? It should be constant at idle, right?

Now again, I am seeing 8-0-8-0. Is 8psi too much? Will that cause it to flood? I can actually see fuel coming out of the carb.
Am I seeing the pressure fluctuate because it is missing due to the flooding.

asphaltburner · 07-21-2009, 12:47 AM

Yo! My 600 Holleys' paperwork states that it is designed to operate at 5 to 7 psi. I have my regulator dialed in at 7 psi and runs perfect. Perhaps that will help for an FYI.
Fuel coming out of the carb is WRONG! Sounds like you may need a new inlet valve for your float bowl.
And the supply pressure should be constant.
Todd.

jdurant · 07-21-2009, 08:30 AM

Thanks asphaltburner. Yeah, something is definately wrong. Just trying to figure out if it is the brand new pump, or the brand new carb. I don't think I can get a good fuel press. reading because the carb wont allow it to run.

07-19-2009, 08:50 PM	#1
jdurant Senior Member Join Date: Dec 2007 Location: Houston, Texas Posts: 679	Fuel pump/flooding/psi? Friday I started smelling gas. Noticed a little trickle of fuel coming from the fuel pump where the two halves meet. So, I installed a new fuel pump--stock replacement for my stock 305 with new quadrajet. Now with the new fuel pump, the truck will barely start. It floods. I teed a pressure guage in the fuel line and it reads 8-0-8-0-8-0-8-0. I think it should read like 4, right? And that is a constant 4 right? __________________ Joseph 87 Turbo Buick 92 5.0 Mustang coupe 87 GMC Sierra SWB 82 Chevy K5 Blazer 2wd

07-19-2009, 10:09 PM	#2
powerdriver 1958 Kid's Mechanic Join Date: Nov 2006 Location: Kansas City Posts: 8,241	Re: Fuel pump/flooding/psi? would think it would be closer to 6 lbs,Is there a chance that some dirt may have gotten through to the carb?

07-20-2009, 09:53 AM	#3
jdurant Senior Member Join Date: Dec 2007 Location: Houston, Texas Posts: 679	Re: Fuel pump/flooding/psi? Yes, there is a very good chance of that. It's a long story, but I thought I was over that problem, and had run enough fuel and carb cleaner through it. It was running fine before I changed the fuel pump. Could this new fuel pump with the 8-0-8-0-8-0-8-0 psi be causing it to flood out. When you look at the guage, it should be constant, huh? __________________ Joseph 87 Turbo Buick 92 5.0 Mustang coupe 87 GMC Sierra SWB 82 Chevy K5 Blazer 2wd

07-20-2009, 06:31 PM	#4
powerdriver 1958 Kid's Mechanic Join Date: Nov 2006 Location: Kansas City Posts: 8,241	Re: Fuel pump/flooding/psi? What brand pump?There is a thread running with almost the same problem for cheap imported fuel pumps. http://67-72chevytrucks.com/vboard/s...d.php?t=353676

07-21-2009, 12:47 AM	#6
asphaltburner Registered User Join Date: Jul 2008 Location: Ault, Colorado Posts: 862	Re: Fuel pump/flooding/psi? Yo! My 600 Holleys' paperwork states that it is designed to operate at 5 to 7 psi. I have my regulator dialed in at 7 psi and runs perfect. Perhaps that will help for an FYI. Fuel coming out of the carb is WRONG! Sounds like you may need a new inlet valve for your float bowl. And the supply pressure should be constant. Todd. __________________ '78 3/4 ton 4x4 custom "Todd-built" FRANKENTRUCK! Last edited by asphaltburner; 07-21-2009 at 12:49 AM.

07-21-2009, 08:30 AM	#7
jdurant Senior Member Join Date: Dec 2007 Location: Houston, Texas Posts: 679	Re: Fuel pump/flooding/psi? Thanks asphaltburner. Yeah, something is definately wrong. Just trying to figure out if it is the brand new pump, or the brand new carb. I don't think I can get a good fuel press. reading because the carb wont allow it to run. __________________ Joseph 87 Turbo Buick 92 5.0 Mustang coupe 87 GMC Sierra SWB 82 Chevy K5 Blazer 2wd



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