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EFI tank with carb sending unit

Discussion in 'The Garage' started by Mastiff, Nov 18, 2006.

  1. Mastiff

    Mastiff 1/2 ton status Premium Member

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    This stinks. My 83 K5 is set up with TBI with an in-line fuel pump. When the tank rusted through, I ordered an EFI tank to get the anti-slosh baffles. I decied to just keep the in-line pump instead of getting the in-tank setup, partly due to laziness and partly because I kind of like how easy it is to replace the pump right now.

    But now it looks like the baffles interfere with the old style sending unit. Has anyone else been through this? The sending unit will fit in backwards, but then I'd have some crazy routing to do to get the hoses all installed.

    What the heck should I do? I could try to return the tank, which would be a huge pain, plus then I'd lose the anti-slosh. I'm leaning towards the backwards install, but I'm a little paranoid about the extra long hoses chafing on stuff. :doah:
     
  2. southernspeed

    southernspeed 1/2 ton status GMOTM Winner

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    Personally I'd invest in the stock set up. My stock pump was still working fine with 160,000+ miles on it. In tank they're quieter, run cooler and are out of harms way.
     
  3. dyeager535

    dyeager535 1 ton status Premium Member

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    Can you shoot a pic of the earlier setup?

    I'm surprised there is an issue, if anything the TBI unit would logically be larger since it has a pump attached to it...?
     
  4. Mastiff

    Mastiff 1/2 ton status Premium Member

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    Here's a pic of the sending unit. The problem is that the dogleg in the pickup hits the baffling. I got a plastic tank, so maybe stuff is different, but the baffling is a U shape with the opening to the back, so if I put the sending unit in backwards, the dogleg has room.

    I also attached a pic of how I'm looking at solving this. The sending unit is backwards, and I just have a bunch of extra hose to make the connections. Kind of a hack job, but it should work.

    sending_unit.JPG

    tank.JPG
     
  5. mouse

    mouse 1/2 ton status

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    Yes, the older pickups will have problems with the new style tanks. I tried it out when I converted to TBI.

    If your replacement tank is like mine, the baffles are steel. You should be able to break the spot welds that hold the baffles inside with a small pry bar - although I would personally go with a stock TBI pump. The baffles will only help you with the in-tank pump.

    Plus, they're quiet, and as mentioned earlier, pretty reliable.

    Don't forget to change the $7 sock while you have it apart.
     
  6. Mastiff

    Mastiff 1/2 ton status Premium Member

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    I understand that the in-tank pumps are pretty reliable. I'm just not in the mood to deal with all the complications right now, of adapting to the EFI sending unit and installing all the high pressure plumbing.

    Did you end up installing all new steel line for your conversion?

    Why won't the baffling help with an old style sending unit? Either way it should reduce the likelihood of sucking air it seems.
     
  7. Confedneck79K30

    Confedneck79K30 3/4 ton status

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    you can cut that pickup and have it rewelded sideways...
     
  8. Mastiff

    Mastiff 1/2 ton status Premium Member

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    I don't have the welding skill to pull that one off. I suppose I could find someone to do it for me.
     
  9. Confedneck79K30

    Confedneck79K30 3/4 ton status

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    if you really want to use it that way, it wouldnt cost more than 30-40 bucks to have it done...
     
  10. Can Can

    Can Can Pusher Man Staff Member Super Moderator

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    Other than the noise issue(which isn't that bad), you should have no problem with an inline pump. FWIW, I conquered some vapor lock issues I was having with my carbed 305 by eliminating the stock block-mounted manual pump and switching to an inline electric pump. That was over 11 years ago, and I have yet to have a problem with it. Mind you, as previously mentioned, my application was for a carb, so I can't say for sure that the higher pressures required by a TBI truck wouldn't cause higher pump temps.......:thinking:
     
  11. mouse

    mouse 1/2 ton status

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    I ran all TBI fuel line from a donor truck when I converted. I quite frankly, bending the line and making it fit properly (from a suburban) was the most difficult part of converting the truck to TBI.

    You could use rated fuel hose and attach to nipples on the TBI tank.
     
  12. dyeager535

    dyeager535 1 ton status Premium Member

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    Carbs have a fuel bowl and don't need the fuel pressure of the pump to work constantly. EFI you lose fuel pressure from sucking air, the engine dies essentially immediately.

    Certainly won't hurt to run it with baffles, if you get in some odd situation with a near empty tank it would help a bit, but I assume that would have to be pretty extreme. I'm sure some have had it happen though! :)
     
  13. Mastiff

    Mastiff 1/2 ton status Premium Member

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    I'm running TBI though, not carb. I'm just using an in-line pump instead of in-tank.

    I can't get the darn thing to prime though. The tank is in, but it won't start. :mad:
     
  14. dyeager535

    dyeager535 1 ton status Premium Member

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    My mistake on the EFI issue. You want baffles. :)

    Are you getting injector pulse? First thing I'd check when trying to start an engine after an injection swap, no power where/when you need it is the most common problem I see people have. (IE, no power while cranking on the injection or ECM circuits, etc)
     
  15. Cricket

    Cricket 3/4 ton status

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    I have a few questions to help narrow it a bit.

    1. What type of fuel pump are you using?
    2. Where is it mounted?

    EDIT: just came across your other post. The 5001 should solve your problem if it is a pump-style issue. Worked for me.
     
  16. Mastiff

    Mastiff 1/2 ton status Premium Member

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    I'm hoping it's a pump issue. I'm just confused because I had everything working fine, and now that I replaced the tank I can't get it to go again. Nothing changed on the computer/injector/etc. side, so all that should still be good.

    I was sure that it would go once I primed it. I can only guess that naybe the fuel filter is the issue.
     
  17. Cricket

    Cricket 3/4 ton status

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    Nothing changed on the computer/injector side.

    What exactly did change? If you added the inline filter afterwards is it facing in the correct direction? Unless your fuel pick-up is completely blocked everything should work, providing you didn't make any other minor changes that created a problem.

    How about tank venting?
     
  18. Mastiff

    Mastiff 1/2 ton status Premium Member

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    I changed the tank and replaced the sending unit with the same model. The only thing different configuration-wise is the extra hose required to have the sending unit in backwards (see the pic above). Maybe the extra hose is more than the pump can take.

    The lines were all evacuate of fuel, so I figured it was related to getting everything primed.
     

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