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Swapping in TBI tank and pump

Discussion in 'The Garage' started by Mastiff, Oct 5, 2006.

  1. Mastiff

    Mastiff 1/2 ton status Premium Member

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    My tank sprung a leak, so now I'm thinking about what it would take to switch to a TBI tank and in-tank pump to support my EFI conversion (83 K5). Right now I have an in-line fuel pump.

    First, do most people agree that the in-tank pump is better? In a way, I like the in-line pump because I can carry a spare and it's easy to replace. I haven't yet experienced any issue with sloshing or anything.

    If I decide to go with the in-tank pump, I was looking at this tank:

    http://www.autopn.com/store/pc/viewprd.asp?idProduct=7467

    It's polyethylene instead of steel, which seems good in rust country. Any opinions?

    Would an 89-91 sending unit be correct (pic below)? I'm not sure I understand what the big pipe is for, any ideas? I understand I need fuel out, fuel return, and vent. What else?

    Also, will my existing lines connect to this sending unit as is, or will I need to splice in some hose or something? At present I feed off the rigid lines halfway up the frame, then go with rubber hose to the TBI.

    [​IMG]
     
  2. JUNIOR-K5

    JUNIOR-K5 1/2 ton status

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    I have a sending unit with working pump for 31 gal. tank out of a 90 suburban if your intrested. Your existing lines will not work if they dont have threaded ends. I did the same swap in my k5.
     
  3. ChickenRammit

    ChickenRammit 1/2 ton status GMOTM Winner

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    the big pipe is the air vent for your filler neck. you'll see where it goes when you drop your old tank. as for your fuel lines, you'll need new ones. you should be able to get the lines from an '87 and up blazer, suburban, or k10. you can also have hoses made by a hydraulic hose company, but they usually have to use AN fittings and then you have to use saginaw adapters to connect to the GM sending unit. i personally prefer the in tank pump because most people say the inline pumps are unreliable and that they are kind of loud.
     
  4. dyeager535

    dyeager535 1 ton status Premium Member

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    4th for that sender is EVAP. Your truck will already have that of course, if it's still there.

    If you can get a polyethylene tank with baffles, that would be fine I think. I assume they would handle all sorts of vibration and shock (not directly to the tank of course) or they wouldn't be sold. Metal should be good too, but how long did the stock one last on your truck? That would be my benchmark. Paint if you want to add a bit more life to it I guess. The aftermarket tank I got was obviously galvanized or whatever on the outside as well as inside.
     
  5. Mastiff

    Mastiff 1/2 ton status Premium Member

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    Yeah, I understand what that big pipe is for now. I should have remembered from when I replaced my K30 tank.

    Anyone else have opinions on in-tank vs in-line pump? Maybe I should post a poll. :wink1:
     
  6. JEBSR

    JEBSR 1/2 ton status

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    In my experience I would say the in-tank pump have more possitives than negs. Can not get hit on the trail, Don't get wet when in water, no corrosion and no impact.
    As for the tank you need to have a good shield for the tank so it doesn't get punctured. Also poly tanks eventually do dryrot and start to crack, but that would be years down the road.
    Don't know if you know, but if you can get an older tank (and you want a used one) You can use a tank off of a carberated model as well. You just have to switch the sending unit, pump housing. I am running a 77 tank in my 87
     
    Last edited: Oct 6, 2006
  7. Mastiff

    Mastiff 1/2 ton status Premium Member

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    You mean in-tank? My in-line is on the frame rail. It's almost impossible to get hit, but it will get wet and possibly corroded. The one I'm using is from a Ford truck application.

    Don't the OEM's all use poly tanks these days. My Jeep tank is plastic.

    The old tanks don't have the baffling though, right?
     
  8. JEBSR

    JEBSR 1/2 ton status

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    Yea I meant in-tank. I have had wires snatched out of the inline setup as well when going over tall brush.

    Not all oem's use poly tanks. They are not bad tanks, but they do have a tendency to crack after years of expanding and contracting. But like I said earlier it would years.

    I have not had any problems with mine as far as the baffling goes. I've had it on some very steep inclines with 1/4 tank and no problems. I had it stumble once when taking a 90* turn. However I was headed to the gas station and added just over 30 gallons of gas to it so I believe it would have done it anyway (baffled or not). Just my oppinion though.
     

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