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Old 07-04-2003, 01:07 PM   #1
low 84
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fuel pump return line?

ok i'm changing my truck over from the stock style pump that uses a return line to a holley mechanical pump. one of the hard lines that runs from the tank to the pump is big and one is small. am i right in guessing the big line is the feed and the small line is the return?
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'51 F100, backhalf with a narrowed 9 and coil overs, 18.5" mickeys, monte front clip, +400" sbc in the works

'05 1500 Crew Cab

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'84 swb 5/7 drop, solid cammed 408 w/ fully ported dart heads, th350 w/ 10 inch hughes, 12 bolt w/ 3.73 richmonds and a locker
'80 swb 4x4 in progress: 7" lift, 350 th350/np205, d44 and 1.5" ORD tie rod, 14BFF w/discs , armored diff covers, 40" MTR's
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Old 07-04-2003, 01:51 PM   #2
BigRed
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Sounds right to me. However I'm not positive. It makes no sense that they would run the larger line as the return.
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Old 07-04-2003, 02:50 PM   #3
mike reeh
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if you only have two lines running from the tanks, then you probably dont have a return line. The smaller one is probably the vent. Does it go directly to the fuel pump or to the charcoal canister?

Is your stock fuel pump a 2 port or 3 port? If its a 3 port, it should have a return. 2 ports are just input from tank, and output to carb.

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Old 07-04-2003, 07:46 PM   #4
low 84
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Quote:
Originally posted by mike reeh
if you only have two lines running from the tanks, then you probably dont have a return line. The smaller one is probably the vent. Does it go directly to the fuel pump or to the charcoal canister?

Is your stock fuel pump a 2 port or 3 port? If its a 3 port, it should have a return. 2 ports are just input from tank, and output to carb.

mike
yes i have a three port pump, and inlet outlet and return, i also had the vent line which i removed becuase i'm not running any emmsions equipment. the small line that connects to the fuel pump is the same size as the vent line was and then there is a bigger line goin to the fuel pump aswell. so i'm guessing this is the feed which is the only one i need to keep?
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'51 F100, backhalf with a narrowed 9 and coil overs, 18.5" mickeys, monte front clip, +400" sbc in the works

'05 1500 Crew Cab

RIP
'84 swb 5/7 drop, solid cammed 408 w/ fully ported dart heads, th350 w/ 10 inch hughes, 12 bolt w/ 3.73 richmonds and a locker
'80 swb 4x4 in progress: 7" lift, 350 th350/np205, d44 and 1.5" ORD tie rod, 14BFF w/discs , armored diff covers, 40" MTR's
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Old 07-04-2003, 08:04 PM   #5
mike reeh
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Hmm the two smaller lines are the same size? I find that hard to beleive. There should be a 3/8" which is feed, 5/16" which is the vent and believe it or not the 1/4" is the return. Things may have changed slightly over the years though. This IS general motors we're talking about, and just about anything is possible.

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Old 07-04-2003, 11:29 PM   #6
low 84
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mabey i mistaked the 3/8 and 5/16 as the same size. but the 1/4 is the return? i just cut off the wrong line then, lol
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'51 F100, backhalf with a narrowed 9 and coil overs, 18.5" mickeys, monte front clip, +400" sbc in the works

'05 1500 Crew Cab

RIP
'84 swb 5/7 drop, solid cammed 408 w/ fully ported dart heads, th350 w/ 10 inch hughes, 12 bolt w/ 3.73 richmonds and a locker
'80 swb 4x4 in progress: 7" lift, 350 th350/np205, d44 and 1.5" ORD tie rod, 14BFF w/discs , armored diff covers, 40" MTR's
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