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TBI problems

Discussion in '40- & 55-Series Tech' started by Gumby, Apr 29, 2003.

  1. Gumby

    Gumby Supamod Staff Member s-Moderator

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    I have been having some strange problems with my new TBI. It seems to run out of fuel at high RPM when warm. I had some codes and worked them out. No VSS and no knock sensor mounted yet, but that shouldn't affect stuff much. It does it with or without the EST wire connected.

    A couple of issues I have to run by those of you that have done this. I am using the stock tank with an external pump. I seem to have good fuel pressure all the time. The fittings on my pressure tester leak and a backfiring throttle body has caused a couple of really impressive fires while pressure testing. While testing, it held 11 pounds constistantly, even while it was stumbling and backfiring. I ran it this morning with the fuel inlet line into a 5 gallon can and it seemed to run much better before the return line pumped all the fuel into the main tank. Before I yank the tank, has anybody run a TBI from the main fuel outlet using an external pump without problems? I have to think so. Was the tank different for the F engine on my 74?

    Secondly, I might be having a problem from my intake. It is a Holley Dominator with a square bore to spread bore adapter, then a spread bore to TBI adapter. It's getting pretty tall and might be causing my problem. I would think it would not run well at idle and better at high RPM that way but... Before I change to a regular TBI manifold I could use some input.

    Thanks
     
  2. SpaceGhost

    SpaceGhost

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    Todd,
    I did run my TBI with the stock tank for several months, with an external pump. The tank was a 68 with only the outlet on the left and a vent to the filler tube. I tee'd into the filler neck vent for the return. So yes the stock pickup will deliver enough volume for the TBI, assuming it is clear. The pump was mounted about half way to the TBI and a little lower than the tank.

    Currently I am running mine with a fuel cell and NO vent. The return line connects to the top, the outlet in the lower rear. No problem that I can detect with this setup yet. Makes getting the cap off easy when it's warm out!

    Have you tried running without the gas cap?
     
  3. Gumby

    Gumby Supamod Staff Member s-Moderator

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    I did try taking the gas cap off. No difference.
    I think I'll go get some more gas and try getting the return line off and into the remote gas can to make sure that's the problem. If that does it, I'm going to have to go to a poly tank cause I'm gonna beat the snot out of this one.

    Thanks, Mike
     
  4. Gumby

    Gumby Supamod Staff Member s-Moderator

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    That did the trick. I'm getting no volume out of the stock output line. I sure wouldn't be surprised if it was just mine as it sat for a long time. Now I gotta order a poly tank from someplace. Any better source than JTO?
     
  5. PHAT MAX

    PHAT MAX

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    cool cruisers has them...
     
  6. SpaceGhost

    SpaceGhost

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    Glad ya found the problem Todd. Be sure to wash the poly tank out real good, there will be plastic scraps in there. Now lets go wheeling the 15th at Attica!
     
  7. theo

    theo

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    Are you talking about corrosion now? Outlet getting mucked up with chunks of rust? I've reconditioned a couple of tanks now with the POR-15 treatment. It's time consuming but it works well. I did my '54 Chev pickup tank last year and a good sized compressor tank last month. Both worked like a charm.
     
  8. CruisinGA

    CruisinGA

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    I installed a CCOT poly tank, in October, either get their hose kit with it or go ahead and buy a couple yards of 1/4" fuel hose and a couple feet of the breather hose, and a Napa hose adapter for the filler neck tube. And some small hose clamps. I used small pieces of copper tube to connect to the fuel pipes coming out of the floor. The hookups on the CCOT tank are not the same as on the stock tank. Other than that its a very easy install. I did it back before I knew anything in two days after school before starting my homework, mostly cause I had to go buy hoses, if I had had it all it would have been a one afternoon day install.
     
  9. bodacious

    bodacious

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    gumby.. io wouldnt buy a poly tank.. i had one and threw it away.. it has no baffels and is a lower capacity than the stoock tank.. ( and that means you cant run lower than 1/4 tank.. which means buying gas every other day )

    go buy a new stock tank 74 later i think.. its like 200 bucks.. well worth the cash.. and your truck wont stink like a texaco sation when it sits in the summer sun like a poly tank will...

    poly tank... = worthless.... imo