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Thread: need help with the fuel system on the 86.

  1. #1
    Join Date
    Sep 2005
    Location
    North Georgia
    Posts
    181

    Smile need help with the fuel system on the 86.

    Alright guys, I need some advice. I have asked about 20 people about my fuel system and have about 21 different opinions. They range from hooking up what I have to the factory lines using braided and screw clamps to all hard line, tapping into the tank, all out fuel system costing about three grand! There has to be a praticle way to run a good fuel system. Here is what I have...

    The truck was a DIESEL. The motor is a 98 LS1 with a SINGLE fuel line setup. I have bought a Walbro inline pump from Allen and a Aeromtive regulator with a return line out the bottom. So, the regulator will see full pressure from the pump, give the motor 58psi and dump the rest into the return line and back to the tank. The truck has 3/8 line and a 5/16 line coming from the tank. I assume the smaller is a vent line, or was it a return for the diesel?
    With all that being said ( I know its long but I have been fooling with this forever) What to do now? My original plan was to use the factory lines front to back with braided line and smooth screw clamps, then Earls fittings at the regulator and the rail. Now I have 2 problems. People are telling me both lines are too small and the splices will not hold up to the pressure. Most seem to suggest using nothing factory but the tank. Tapping into the tank with a 1/2 supply and a 3/8 return. Is all that really needed? I do plan on adding a magnacharger. I don't want to spend all this time and money and then have to re-do it. On the other hand..all you need is 58 psi at the rail and no leaks. There has to be a simple way. Thanks for any help
    BTW. the truck has 2 tanks but that would make this even worse. my plan is to plum one tank and use the other as a reservior with a small pump and a switch to pump from the reservior tank into the other.
    Last edited by 86 Silverado LS1; 09-30-2007 at 12:32 PM. Reason: double negatives in conjuction with a past participle
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  2. #2
    Join Date
    Dec 2006
    Posts
    4,033
    i hadnt done this conversion but reading what you have it would seem 5/16 and 3/8 would work just fine 1/2 would be over kill, whats needed it getting 58 psi like you mentioned to the rails.. have you tried the stock lines? the larger of the lines is gonna be a return line or vent line the smaller line would be the feed line to rails or regulator. ( i would think) as for splicing mine are spliced with hose clamps and its been that way almost a year without problems .... sorry couldnt be a big help but i hope ya figure it !!!! good luck

  3. #3
    Join Date
    Mar 2003
    Location
    San Marcos Texas
    Posts
    4,393
    I used 3/8" on my '81 and it worked fine even turbocharged. I ditched the twin tanks and installed a Suburban tank in the rear where the spare used to sit. I used a Walbro intank pump with the Areomotive regulator.
    2006 Superior Blue Trailblazer SS AWD, Stock as a rock

    Sold: 2002 GMC Sportside Denali front end with a 2002 LS1, FLT level 5, Yank 2600, Trick Turbo, T76, Nelson intercooler, 60LB injectors, Warbro fuel pump, Eaton locker, Magnaflow, 3.42, Nelson Performance Tuning (speed density).

    Sold: 1981 GMC LB RC 1500 2002 4.8L 4L60E 12 bolt 3.73 Richmond Lock Right AC PS Nelson Performance tuning

  4. #4
    Join Date
    Oct 2005
    Location
    Baton Rouge, LA
    Posts
    997
    Seems like I get PMs from more than one person about fuel setup for the 80s model C10s.

    I used the stock valve switching assembly with an inline pump & filter. The pump was a 255lph-rated pump from a Procharger kit. The feed lines were of the same size as the stock lines, and interconnected using Russell AN fittings. The return lines also used the same as stock with matching fittings. This has worked extremely well for me, but I will warn you that running the level of fuel below 1/8th of a tank is not a good idea... as it is difficult to get fuel flowing if you have any ounce of sediment in the bottom of the tank. Don't ask how I know this. As posted in my conversion thread, replace OBS rubber lines with high pressure fuel lines. You wouldn't want to be caught driving when weaker lines collapse under vacuum.

    Good luck!
    Test-n-Tune (Nov 23, 2008) - 13.65s @ 98mph

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