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Tbi Pump and sender in carb mech tank?

Discussion in 'The Garage' started by ProJunkRacing, Jul 19, 2005.

  1. ProJunkRacing

    ProJunkRacing 1/2 ton status

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    will a tbi pump and sending unit work in a carb chevy blazer tank that was orginally mechanical pump just sender? i need to know if anybody runs this or has thanks . the hole looks similar in size but has anybody done it ?
     
  2. ProJunkRacing

    ProJunkRacing 1/2 ton status

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    see it willfit in the tank butwht i need to know is if it is the right sizehole
     
  3. R72K5

    R72K5 Banned

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    all the ones before 87 ive pulled so far have ben large sender hole size

    and ive always wanted to know if all the tanks were same 86 older and/or 87 up,

    or 85 v-6 TBI and up

    i know a bunch of ppl on here know the answer

    so lets hear it

    thanks
     
  4. dyeager535

    dyeager535 1 ton status Premium Member

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    All the holes are the same.

    Difference is in the baffles used in the '87-91 tanks for injection, and the depth of the tanks which changed how "tall" the sending unit is.
     
  5. R72K5

    R72K5 Banned

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    so whats that all mean ?

    are screwed if put tbi unit in carb tank or carb unit in tbi tank ?

    no way to make it work ? change float arm length or bend/angle ?

    no ?

    hmm
     
  6. dyeager535

    dyeager535 1 ton status Premium Member

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    Say you've got an '81 K5 w/31 gallon tank. You want to install TBI sender out of 31 gallon 1991 K5 tank. It will work with no problems.

    The "problem" is just that the TBI tanks all came baffled. If you get towards empty and get the truck on an incline, if the fuel pickup doesn't see any fuel, the engine will stall pretty much instantaneously.

    Baffled tanks use a well that captures fuel on flat ground, so when you are at an angle, you have the pickup submerged until that well goes dry.

    Stock baffled tanks are oftentimes junk by now, it's pretty typical (at least on donor trucks) that the plastic baffles are broken, which means they are at that point no better than a non-baffled tank, plus you have to remove all the pieces or the sender gets beat up. It appears a small impact with a fair amount of gas is typically enough to break the baffles off the mounting studs, and they aren't really repairable.

    Aftermarket baffled tanks are right around $130, not bad for a brand new all steel design.
     
  7. ProJunkRacing

    ProJunkRacing 1/2 ton status

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    so can i make it work with a tbi pump my tank is a carb tank thats all i need to know what to do to make it work?>
     
  8. dyeager535

    dyeager535 1 ton status Premium Member

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    Yes, as long as tank depth (capacity) is the same, any sending unit will fit in any tank. (within what we are talking about of course)
     
  9. CyberSniper

    CyberSniper 1/2 ton status Premium Member

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    A shallow K5/Suburban tank (9" ~23 gallons) seems to take the same sender or sender/pump as a pickup truck. The deeper K5/Suburban tanks (11" ~34 gallons) take a longer sender/pump. They all have the same size hole for the sender to go in (and is the same on S10s, IFS fullsizes, et cetera... no idea on length) and use the same lock ring but some use an O-ring and others use a gasket.

    The tanks changed over the years, mostly in the form of the filler neck vent. Some go all the way to the tank, others go into the side of the filler neck.

    In 87, with fuel injection, they got a small cup on the bottom of the tank to use as a sump. In my experience, these little guys do just as good of a job of keeping fuel out as keeping it in. Some vehicles, especially IFS chevys with the 33 gallon tank, seemed to have gotten actual metal baffles in them to prevent fuel slosh. These usually break off and ruin the sender.



    My wheeling rig has a carbureted 1979 K5 34 gallon fuel tank in it with an 1987C10 (20 gallon tank) sender in it. The pickup is a solid 2" from the bottom of the tank.
     
  10. R72K5

    R72K5 Banned

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    interesting

    getting some good info in here now

    any more ?

    good luck :D
     
  11. ProJunkRacing

    ProJunkRacing 1/2 ton status

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    how about in tank sending unit with inline fuel pump?
     
  12. dyeager535

    dyeager535 1 ton status Premium Member

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    You could do it, but you'd be MUCH better off selling a working TBI sending unit to someone that wants it, and getting a carbed sender.

    The fuel pump ends up being part of the pickup tube for the fuel, without a pump in place, you'd need to lengthen that line to the bottom of the tank, (steel line in carbed senders) then deal with trying to somehow filter that line.

    I really don't know how easy it would be to pull fuel through one of the stock pumps, it certainlt can't help fuel flow, even if it is possible.
     

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