Author Topic: Please help with fuel line.......  (Read 5490 times)

Offline punkinbizkit

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Please help with fuel line.......
« on: November 09, 2007, 12:00:50 am »
I swapped a 94 350 into a 84 changed it from tpi to carb, I also swapped out fuel tanks out of the 94. My question is the fuel pump out of the 94 has two lines coming out of it but my carb (quadrajet) only has one gas inlet what do I do with the other line? I know it is a return line but do I need it with a carb, where does the return hook up or can I just seal it off or what. And can I use the existing lines in the 84 to run the gas to the carb or does that fuel pump need bigger lines. Please help me with this, Im kinda new at this..Thanks.

Offline Blazin

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Re: Please help with fuel line.......
« Reply #1 on: November 09, 2007, 07:02:31 am »
First thing that comes to mind for me is what are you running for line from where the 84 leaves off ( Old mechanical fuel pump location ) To the carb. You need high pressure rubber or metal for the electric fuel pump.
 Second thing is a Carb doesn't need as much pressure as a TBI. How are you cutting the pressure down?
 Third most mechanical pumps have a return line to the tank. Does your 84? Can you use it?
Some people are like Slinkies. Not really good for anything, but they still bring a smile to your face when you push them down a flight of stairs

Offline punkinbizkit

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Re: Please help with fuel line.......
« Reply #2 on: November 09, 2007, 08:05:35 am »
I have the high pressure hose so I can hook it up to the metal lines by where the old mech pump should have been, I am using a fuel regulator to slow the fuel down, remember I am using the fuel pump in the fuel tank out of the 94 it has a elec. pump in it. By using that pump where do I hook up the return line to. Thanks...

Offline Captkaos

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Re: Please help with fuel line.......
« Reply #3 on: November 09, 2007, 11:38:36 am »
If you are feeding it with the factory pump and you are using a regulator, does the regulator have a return port?  The factory 94 pump is pushing 13lbs of pressure, 7lbs more than what the carb wants.  If you don't have a place to connect the wire, I would plug it...

Offline punkinbizkit

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one more question about the fuel...`
« Reply #4 on: November 09, 2007, 01:28:55 pm »
there are four wires coming of the fuel pump of the 95 but because my truck is a 84 i dont know where these wires go can someone break them down for me and tell me what i need to hook up. it is going to a 94 350 that i converted from fuel inj. to carb, sorry for so many questions but this is my first build. im trying to restore my late grandfathers truck myself. thanks

Offline DnStClr

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Re: Please help with fuel line.......
« Reply #5 on: November 10, 2007, 09:01:05 am »
Captkaos is right- the in-tank fuel pump is making too much fuel for the carb and you need to return the fuel via the regulator if the carb doesn't have a return line. So you should have a 3/8 line and a 1/4 line coming out of the tank going to the regulator. then a 3/8 line going from the regulator into the carb.
As the fuel from the tank (13-15lbs) is regulated down to 4-7 lbs, the extra fuel has to return to the tank thru the 1/4 line. 
 You must like your carburetor. The efi tuned port system was developed as an upgrade in the fuel delivery. 
Don
87 Chevy Silverado

Offline DnStClr

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Re: one more question about the fuel...`
« Reply #6 on: November 10, 2007, 09:06:22 am »
Yeah. I think he's trying to keep the two issues separated. I was wondering how the fuel pump is going to get it's power. Doesn't the signal originate from the computer on an efi system?
Don
87 Chevy Silverado

Offline 123 pugsy

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Re: one more question about the fuel...`
« Reply #7 on: November 10, 2007, 09:15:23 am »
Does this post belong to another thread? The 95 truck has an in tank fuel pump. If you are running a carburetor on this engine just use your 84's tank. Or did I miss something here  ???

Does the 94 have a place on the block for the fuel pump? If not, I believe this is the reason behind the electric fuel pump.
Pugsy
76 C10 LWB
TPI 350