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EFI Fuel Tank / EFI Wiring (TBI) Qst

Discussion in 'The Garage' started by nmaggie99, Jun 24, 2005.

  1. nmaggie99

    nmaggie99 Registered Member

    Jun 24, 2005
    Likes Received:
    Anchorage, AK
    Another EFI question (New member long-time reader). Has anybody done this with a '67-72??? Thoughts on the wiring or Painless harness??? and Thoughts on the '91 tank???

    I am currently working on a 72 4X4 Blazer and am installing a complete motor, trans, transfer case (NP241) from a '91 Blazer that I am parting out. I have everything ready to install but have questions concerning the install of a electronic fuel pump for the TBI. Other than using the stock tank with an in-line aftermarket pump, can I use the '91 tank complete??? It appears that it is to long (front to rear). How have others done this??? Problems?

    Also concerning wiring.... I still have the '91 and all the wiring. I pulled the engine harness (Computer to fuse-box) and am working on the removal of the under-dash harness. This is where it gets complicated.... Has anybody done this as well or should I cough up the $289 for a Painless harness?????? What speedos work with the electronic outout on the 241???

    Thanks for the help in advance.... My goal is to install next week and have running by August....
  2. azblazer

    azblazer 1/2 ton status Premium Member

    Jul 20, 2003
    Likes Received:
    Grand Junction, Co.
    The tank is usable in your frame...my old 31 gallon tank from my 79 K5 resides in MOSESBURB's 72 sub....pm for details...and its the best way to go.

    I've done the conversion twice in gen2 K5's...next time i'd like to have a welding shop cut the ends off the tbi sending unit and tig weld on some standard AN fittings so i can get away from using all the stock fuel lines from a 87-91 K5...the two lines from the frame to the tbi run $45 and some change from gm but they are not very forgiving....turbocity.com sells saginaw to AN fittings for the back of the tbi for $9.99 a piece...the an lines and fittings last forever plus a guy could make an aluminum block before and after the fuel filter so you would have a port to check fuel psi before and after the filter....cummins compucheck fittings work nicely....

  3. CyberSniper

    CyberSniper 1/2 ton status Premium Member

    Apr 21, 2003
    Likes Received:
    Chelsea, MI
    If you split the loom off the electrical harness that runs to the rear of the K5 you'll find the wires you need for the TBI tank. Unplug them at the tank and pull them through the frame. You can just re-run the wires back on your firstgen. You can pull the crossmembers out of the TBI K5 and put the crossmembers and tank in the firstgen.

    Buy some white electrical tape and pull the interior harness out of the TBI K5 while marking the ends of everything you unplug. It's a pretty simple harness. Once you get it out you can eliminate the things you don't need. The ECM harness pulls out through the firewall.

    I used tube I bought from Summit to replumb all the lines in my wheeling rig. I used fuel injection rubber hose for connecting to the hardlines. I like in-tank pumps because they run cooler and are quieter (usually).

    Save all the ends of the hardlines on the TBI K5. You can put barbs on these lines so you can plug them into the factory braided line and then hook rubber high pressure fuel hose to them.

    The more care and time you spend on the TBI K5's disassembly the easier it'll be to put it in the firstgen.

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