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converting from TBI to TPI

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by sjeccles, Aug 6, 2002.

  1. sjeccles

    sjeccles Registered Member

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    Has anybody converted their TBI over to TPI from a late 80’s camero? I might be able to pick up a TPI and was wondering how hard this would be and if it would be worth the expense
    Thanks
     
  2. sjeccles

    sjeccles Registered Member

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    surely somebody here has done this
     
  3. Blue85

    Blue85 Troll Premium Member

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    I assume that you are almost starting over to do this swap. Maybe the only parts you could reuse are the O2 sensor and the distributor, but I don't know for sure. The intake, throttle linkage, wiring, computer, injectors, etc. are all different. I think TBI runs around 12psi of fuel and TPI around 55psi, so even the fuel pump would probably have to be changed.

    I think that you could just do a general search on TPI swap for the information. I think the only advantages to starting with TBI vs. a carb is that there are less vacuum lines to remove and deal with and the stuff mentioned above.
     
  4. 88Jimmy

    88Jimmy 1/2 ton status

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    Yes I think its worth it, Search here for TPI and you should find everything you need
     
  5. dyeager535

    dyeager535 1 ton status Premium Member

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    As long as you are getting EVERYTHING from the Camaro, (intake, distributor, un-cut wiring harness, fuel pump, etc) it will be worth it. You end up missing pieces, and its gonna cost you. Year also is significant, both in design, intake, and wiring harness integration into the rest of the vehicle (VATS, etc)

    There are a few things that are 305 or 350 specific, (wiring harness is not one of them) such as knock sensor and injectors, so realize that could be additional expense as well.

    If you can get it cheap and complete, (in good shape)even if you decide not to use it, you should be able to get $300+ out of it, and that would be a good deal for someone else.

    It will take time to figure out the swap, but a later (TBI) truck should be easier to convert over to TPI than an earlier one...I bet a lot of the wiring plugs (fuel pump feed, etc) are swappable from the Camaro fuse panel to the truck fuse panel plug.

    Don't forget, fuel lines are on the wrong side for TPI as well.
     
  6. tmanofcali

    tmanofcali 1/2 ton status

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    havent done the tbi to tpi swap, but i did do the carb to tpi swap.best thing to do is to ask questions and read up on it. its not that hard of a swap if you read up on it and take your time. if you send me a pm i will forward some pm's i got from blazinor when i was asking questions. i will try to answer any questions you may have.

    later, todd
     
  7. 87GMCJimmy

    87GMCJimmy 1/2 ton status

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    I did this swap and it's not that bad. The fuel pump from the camaro replaces the trucks perfectly. You already have 2 fuel lines, just need to route them to the front of the engine block. You can reuse many parts between the two systems. Distributor, ESC, IAC, TPS, Coolant temp Sensor, coil, Vss, brake switch etc. You can rework the trucks stock wiring harness pretty easily to run TPI, buy a painless one, or start with the camaro's. I bought the painless but if I was to do it again I would modify the stock truck wiring. The performance gains were pretty amazing between the two systems and I got better MPG's. I used the TPI for 2 years with absolutely no problems until the motor start sounding like a diesel.... and I'm still working on fixing that! If you have any more specific ?? let me know.

    Hope this helps.
    Mike
     
  8. BurbinOR

    BurbinOR 3/4 ton status

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    The guys have it pretty much covered. Did it from carb to TPI, so it was more of a challenge, but worth every bit of work. Biggest difference *safety wise* is the pressure TPI runs at (43.5 psi) - I've never seen a TBI truck setup so I can't say what they have for sure, but putting new fuel lines, or at least adding in more steel line where there is rubber now is a good move. I only have rubber in the engine compartment in the form of factory IROC supply and return lines.

    What year Camaro is it? Early models before 89 were MAF (mass air flow) and use an expensive MAF sensor on the intake air before the throttle body..............later models 90 and up are Speed Density and use a MAP sensor (manifold absolute pressure). Both can be made to work easily unless you're getting radical with camming, etc. Which brings up a good point............make sure if you change cams it is computer compatible.

    Get a good book on TPI - TPI Swappers Guide is one decent one - by John Baechtel. There's another better one I have by Ben Watson called something like "Chevrolet Fuel Injection" or something like that.............sorry I'm not exactly sure on the name but my books are out on loan to a buddy putting an aluminum head L-98 TPI in his '66 Nova.............yum. Lots of other info available on these sites -

    www.jagsthatrun.com
    www.fuelinjection.com
    www.tpis.com
    www.azspeed-marine.com
    www.thirdgen.org (Camaro site that has a TPI bulletin board)

    Any other questions, ask us.............. /forums/images/icons/tongue.gif
     
  9. dyeager535

    dyeager535 1 ton status Premium Member

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    TBI trucks use all hard line or braided flexible line for fuel, (at least on the stuff I got off of an '89 a guy had laying around) so its a bolt in, except for routing. Thankfully. : ) GM was even kind enough to use the same size fittings for the TPI fuel rails as they did for the TBI system.
     
  10. BurbinOR

    BurbinOR 3/4 ton status

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    Thanks, that's good info to know! /forums/images/icons/laugh.gif
     
  11. dyeager535

    dyeager535 1 ton status Premium Member

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    The best part is, there is a lot (relatively) of the flexible sections used on the trucks. I really need to dig up the GM part numbers for this stuff, will be a lot easier to get the line to the other side of the truck using lengths of flexible braided stuff than trying to bend the steel.
     

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