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Anyone swapped in a TBI setup???

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Tommy, Nov 29, 2000.

  1. Tommy

    Tommy 1/2 ton status

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    I want a TPI, but prices are too high for a 10+ year old setup. I have a friend giving me an 88 pickup TBI setup, just wondering if those of you that swapped were happy with results? I kept having trouble out of my Edelcrap carb on the trails this weekend, and I'm determined to have EFI by next ride. Any input appreciated. Tommy

    Drive it Like You Hate It!
     
  2. HarryH3

    HarryH3 1 ton status Author

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    The TBI will make good power and is way less complicated than the TPI.

    If you really want to have multi-port injection but prefer new parts, check out Edelbrock's system. Go to http://www.edelbrock.com/automotive/ and click on the "Multi-Point Fuel Injection" link in the left frame.

    <font color=black>HarryH3 - '75 K5</font color=black>
    http://ThunderTruck.ColoradoK5.com
     
  3. Tommy

    Tommy 1/2 ton status

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    I have swapped a couple of TPI's, super tourque. I just can't believe how much they have gone up in last couple of years. I figued the TBI was easier, just not sure if I'd be happy with it, but I have nothing to lose, it's free. Thanks.

    Drive it Like You Hate It!
     
  4. realsquash

    realsquash 1/2 ton status

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    TBI swap is a cake-job. Get an ECM from the j-yard, a harness from painless or howell-efi.com, and an adaptor from holley to stick the TBI on your favorite intake. Obviously you'll have to install a new fuel pump and an O2 sensor bung in your exhaust (and use a 3-wire one). Get a small-cap HEI (remote-coil) distributor while you're at it. You'll also need a chip that has "VATS" disabled or it won't start.

    They have all the benefits of EFI and they are pretty cheap! Is your engine a stock 350?

    Squash
    http://www.trailrunners4x4.org/users/realsquash
     
  5. Mudzer

    Mudzer 1/2 ton status Author

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    I will be writing an article sometime soon on my TBI setup. I bought all the parts at a local junkyard. I would recommend using the factory harness as much as possible. The harness from Painless and Howell disables the VSS and you need this to run properly. I mean, it will run without it, but I have heard bad things about these "Shortcut" wiring harnesses from the FI companies around. I would recommend going to the Library and getting a Mitchell motor manual for the year you purchase and trace down all the wiring. I traced down all my wiring and eliminated several things:

    Alternator wiring, temp gauge wiring (not to be confused with temp switch, you need it), Oil pressure gauge wiring (likewise, you need the oil pressure switch wiring but not gauge wiring). This "simplified" the wiring some but you still will have a loom full of wires. These items were omitted from the wiring harness because, I have these items already wired up in my existing wiring harness and I wanted to treat the TBI harness as a stand-alone unit. Make sure to get the drivers side manifold from the vehicle with the O2 sensor. Get the Distributor, ECM, Map sensor, VSS (located inside the speedometer on C/K vehicles), ESC, Throttle Body, Coil, Intake, thermostat housing, and wiring harness. Be forwarned, I am not listing all the sensors you will need. The best way to get everything you need is to start at the firewall bulkhead and remove the wiring and all sensors, lines, etc associated with the harness. You can then sort it out later. After I simplified the wiring harness and checked all the wiring routing, I determined there are about 12 wires which need to be hooked up to your system. Most will need 12volts switched and fused. One is for your Check engine light (very important). I found all these parts for under $200. I then bought a fuel tank from a K5 which had the fuel pump installed for $125. This setup is far better than any Howell, Turbo City, Painless wiring setup. The reason why??? GM did their homework much more than these aftermarket companies. Like I said, I plan to write an article on this subject soon. For that matter, I should write a book and profit from it. I have read several TBI swap guides and have found none will tell you "exactly" how to install a junkyard system. They refer you to the motor manual and stress that you read the wiring diagrams and trace all your wiring system down and learn its function.

    My setup came from an 87 Chevy Van with a 305 and it is still in progress. I have not worked all the "bugs" out but I am confident it will be much better than any Carb! They always say - The worst fuel injection system is always better than any Carburator. I would have to agree in the rock climbing scenerio where youre almost always off camber or un-level surface.

    Stay Tuned....

    Mudzer 1978/91 K5
    <font color=blue>www.mudzer.coloradoK5.com</font color=blue>
     
  6. 6.2Blazer

    6.2Blazer 1/2 ton status

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    A good friend of mine recently installed a factory TBI setup onto the 350 in his '89 Jeep. He said it was relatively easy (he's a good shadetree mechanic but definitely not an expert). The longest part of the swap was trying to figure out the factory wiring harness until he pitched it and bought an aftermarket harness which hooked up easily. His system also came off an '87 305 in a van ( he bought the entire van, pulled off the necessary parts, and resold the van). In the end, he only had a total of about $150 in the project.
    The reasoning for the swap was the constant stalling problems with the previous Holley. The new TBI works and runs great on the trail. He thinks he lost a little high end power but the improved throttle response and low end power more than makes up for it.
     
  7. realsquash

    realsquash 1/2 ton status

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    I have to say that howell will make you a harness with a VSS lead. You could also add it yourself. I would not want to use a factory harness just because of its "oldness" and the fact that you'd have to hack-n-splice as much as with a new one from howell (or whoever). The connectors they use are the same ones that GM uses, straight from Packard. Any harness is going to need to be modified to fit your vehicle properly.

    Squash
    http://www.trailrunners4x4.org/users/realsquash
     
  8. Tommy

    Tommy 1/2 ton status

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    Thanks Guys, I have swapped in an LT1, and a TPI, but no TBI. I have a friend giving me everything I need. Where can I get the TBI adapter? I would like to use the performer I already have. I was going to make one, but if there available, I will buy one. What purpose does the speed sensor serve? I'm putting this on my 70K5. How will the setup perform on a 383 with corvette aluminum heads, and a 270 cam. I figured the TBI might be somewhat forgiving? Thanks again guys, As far as fuel, I think a Holley Blue will supply enough fuel. I read where a TBI runs 7-14 PSI, a blue will flow continous 12PSI, so I'll try it inline. Tommy

    Drive it Like You Hate It!
     
  9. BigJim85

    BigJim85 1/2 ton status

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    Hey Mudzer, i look forward to your article. I will, if everything works out, put a crate 350 in to replace my 305 and convert my carb system to TBI in my '85 Jimmy, and I don't really know where to start. Hope to see it soon.

    <font color=red>Call my rig an SUV... And I'll tear your lungs out.</font color=red>
     
  10. realsquash

    realsquash 1/2 ton status

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    First, use a fuel pump made for EFI. You might get away with the holley pump for a while, but I wouldn't go into the woods with it. Also, the Rochester injectors used in the TBI's will take a LOT of fuel pressure. That will allow you to use OEM injectors and get some more flow outta them.

    Look up the adaptor on Holley's website and order it via summit or jegs. Maybe howell-efi.com has them in stock. Maybe turbo city will?

    For your engine spex, you will need to reprogram reprogram reprogram. If you are told otherwise, hang up the phone. You are forewarned! Those parts will net you about 350-400hp, so you'd better get a 454 TBI while you're at it.

    The VSS sensor helps driveability. It will do things like hold the idle speed up a bit on decelleration and a few other things. It isn't required, but it does make the system all that much nicer to operate.

    Since this is not a stock engine, you will need to either learn to program the setup or get real friendly with a local chip-burner with a dyno. Those are very few and far-between. And no, a Hypertech chip will do nothing for you.

    Squash
    http://www.trailrunners4x4.org/users/realsquash
     
  11. BurbinOR

    BurbinOR 3/4 ton status

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    Amen to that comment about Hypertech.............we put in a supposed hot hypertech chip in my 406 for startup as the original custom burnt chip the guy screwed up and left the VATS programming in............that thing made me think I got ripped off on my supposed hot 406/TPI rebuild.........but man, what a difference with the correct chip. Find a custom burner locally, get to know him and if he is good, he will basically know (based off your cam size, motor displacement, heads, etc.) what to start off with to get close.

    <font color=black>'79 - 406 TPI -<font color=orange> K5#5 - <font color=blue>See it at---&gt;http://www.blazzinor.coloradok5.com
     
  12. 1HIHUM

    1HIHUM 1/2 ton status

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    What does it cost for a custom burned chip? I have a ZZ4 crate motor, and would love to go injected! Would I need a unit from a 454 to handle the 350 hp and 405lbs of torque? Or would a 350 unit do the trick?

    [​IMG]
     
  13. BurbinOR

    BurbinOR 3/4 ton status

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    No, my computer and chip are from a 350 ORIGINALLY, but we added 24 lb/hr injectors (versus 19 stock), upsized the throttle body to 52mm (from 48 stock) and had the chip burnt with all those factors (plus as I mentioned the cam profile, cubic inches - 406, heads, etc., putting out over 400HP and 450 lb/ft torque. A chip will cost only around $100-150 depending on your area I guess. Doesn't have to be from a big block, though I have heard some guys say you may want a big block TBI unit for the extra flow. Mine is TPI, so not a direct comparison. Good luck........you'd love injection..........

    <font color=black>'79 - 406 TPI -<font color=orange> K5#5 - <font color=blue>See it at---&gt;http://www.blazzinor.coloradok5.com
     
  14. 1HIHUM

    1HIHUM 1/2 ton status

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    Thanks for the info[​IMG]

    [​IMG]
     
  15. HarryH3

    HarryH3 1 ton status Author

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    Using the factory harness isn't that big of a deal. 99% of the wiring from the computer goes directly to the sensor, injector, etc. that corresponds with it. There are several other wires in the harness that are not part of the engine management system (A/C, wipers, etc). You can either strip 'em out or cut 'em off. (I stripped 'em out of mine to make it look cleaner).

    You'll need to supply power for the ECM, the injectors, the EGR circuit and the fuel pump (and the 9th, cold start, injector on some TPI units). There's also one wire that has to tie into the ignition circuit so the ECM knows the RPM and when to fire the injectors.

    If you understand wiring diagrams, it's not hard to do. If you don't, then spending a few hundred bucks on an aftermarket harness can save you a lot of aggravation. With a degree in computer engineering, figuring out the wiring harness wasn't that big of a deal for me. [​IMG] There also wasn't much in the way of aftermarket harnesses available back in '89 when I did mine. I had to figure it out myself. The factory '87 Corvette wiring diagrams are incredibly detailed so that helped quite a bit!

    <font color=black>HarryH3 - '75 K5</font color=black>
    http://ThunderTruck.ColoradoK5.com
     

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