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TBI conversion!

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

  1. OLDSTEEL

    OLDSTEEL 1/2 ton status

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    I'm looking to get rid of the carb on my 74 and want to replace it with a TBI; Have any of you done this and if so what brand is the best to go with?, I want to go new not remanufactured.

    Thank's
     
  2. TopOff

    TopOff 1/2 ton status

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    Holley seems good...

    I think Howell still makes the TBI setup too.

    I went with the howell for the Factory type parts (except the TBI and fuel pump themselves). This way when a part DOES fail, I can go to my local auto parts and say it is from a '87 Chevy truck... Voila' new part in hand. Comes in handy when (if ever) I go to MOAB, and something were to fail. /forums/images/icons/laugh.gif

    I carry an extra computer, chip and fuel pump with me when I go out.

    I have had this setup for ~ 5 years. NO PROBLEMS.
    *knock on wood*
     
  3. BurbinOR

    BurbinOR 3/4 ton status

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    PM AZBLAZER or azblazor (two different guys)............he's done it twice now. Great guys too............ /forums/images/icons/tongue.gif
     
  4. 85m1009

    85m1009 1/2 ton status

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    I ran a Holley projection system on my truck for two years and it ran fine, except that it would not adjust enough for high altitude. I just swapped it out for a factory TBI from an 87 van. I overhauled the throttle body and replaced all the sensors and purchased flow matched injectors from Turbo City. It started right up and seems to work well. I did have to send the prom off to have the EGR circuit taken out since I do not have provisions for an EGR valve. Pretty easy to do and with a total cost of only $400.00 including the price from the salvage yard and all new sensors and new distributor parts. Much cheaper and easier to find parts for than the Holley.

    Turbo City offers complete bolt on factory style systems for about $1200.00.
     
  5. K5 NUTT

    K5 NUTT 1/2 ton status

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    /forums/images/icons/cool.gif Startin in on the chalet tonight....dumped the headers in favor of factory 87 to 91 stock exhaust manifolds... plus is the o2 sensor port allready there... saturday i'll have the the exhaust hoked up...and hopefully the new fuel tank will be here so i can swap it in along with all the 87-91 K5 fuel lines i scrounged up before leaving phx. I'll be pushing it to have her ready by BB02...but nothing is impossable...lol. Got the harness from the donor 89 Sub half done...so i'm excited to get here done because there is some really good fishin here in grand juction....

    Azblazer
     
  6. azblazor

    azblazor 1/2 ton status Premium Member

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    Matt,
    I advocate using factory TBI (87-94) everything. I have a 79K5 with factory 454TBI in it. My son has a 79K 1/2ton Suburban with a factory 350TBI system on a stock rebuilt 400ci. Both our truck use the all the factory components (computer, TBI, sensors (except VSS - another story), manifolds and wiring harness) We have had exceptional reliability and ease of installation. In our applications both systems control the transmissions also (4L80E and 700R4 respectively). Using the Transmission control with the factory systems IS NOT necessary to have them operate the engine properly.

    A complete TBI setup from one donor truck is my recommended source. If interested you should get;
    Computer.
    Wiring harness from computer into the engine compartment.
    TBI (carburator) with injectors.(has TPS on it)
    Intake manifold WITH all attached sensors /electronic components ( ESC, EGR soleniod, Vapor canistor control, MAP sensor, ETC.)
    Get Knock sensor or buy new one.
    Buy new O2 sensor
    Exhaust manifolds (helps with installing O2 sensor)- otherwise need to weld in bung into exhaust.
    Air cleaner and intake snorkle. (optional)
    Factory manual and wiring diagrams (for donor truck and donee truck)

    We are currently working on TBI'ing a 2.8L V-6 and TBI'ing another 454. I am also working on computer controlling a 4L80E in a diesel application.

    Thats just me though - A LOT of others have had good success using Howell FI stuff and other manufactures, my opinion is stay away from Holley (bad personal experiences) and Painless ( bad rep from others).

    www.jagsthatrun.com has a lot of good resources as well as a whole slew of links in the "LINKS" post
    Also SEARCH the main forum for past threads - there have been A LOT of good discussions and threads and a lot of details covered and questions answered.
     
  7. BlueOx

    BlueOx 1/2 ton status

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    AZBLAZER,

    As you know, I'm doing my swap and will be dont shortly. I saw that you told Matt to get the Vapor canister control. I didnt get that for my swap. This is the first time of hearing about this. If I dont have this thing what
    ill effects will it have on my system? One more. How do I put one on my system

    Thanks,
    Charles
     
  8. K5 NUTT

    K5 NUTT 1/2 ton status

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    TBI engine uses a different charcoal cannister than the earlier years...along with a diff mounting bracket...all it does is hold and store fuel vapor...its a bitch getting the oem vapor line out of a chassis in the bone yard...but you could use the stock line allready in the frame rail..and just add some vacum line to extend it to where the canister is mounted. Unlike mid 80's stuff there is no special circuit to control the vapor can...i still have a new bracket from gm on the work bench and can provide you with the pn#...sometimes its actually chepaer to buy a new part at the dealer than to waste time checking boneyards for one and getting over charged.

    Azblazer
     
  9. BlueOx

    BlueOx 1/2 ton status

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    AZ,

    As unbelievable as this my sound I have a very good friend that owns a very large bone yard here in Houston although there are not any K5's there are a ton of Burbs. Can you say FREE. Like you said it's a pain to get the line out at a bone yard, I can attest to that. I got my feed and return lines from a 90 Burb (just cut them down). What a pain. While I was there I saw the canister and was going to get it but didn't think I needed it. One thing I did notice is that there were some wires that were coming out of the top. Do these wire tie into the harness if so then where?

    Charles
     
  10. K5 NUTT

    K5 NUTT 1/2 ton status

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    What year burb had a wire connector at the vapor can? I'll looky see tomorrow after work....have gm manuals (Helm) from 73 to 99....plus a lot of the big late 80's early 90's electrical diagrams...wil have to research to find out whats up....

    Azblazer
     
  11. BlueOx

    BlueOx 1/2 ton status

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    I believe it was in a 90 Burb. I got most of the little parts for my swap out of that one. I was looking and the wiring diagrams that I copied at the library and it does show a solenoid valve that I don't have on my harness. It's called the AIR DIVERTER SOLENOID VALVE. One solenoid wire is a power and one goes to C1 on the ECM. I'll go to the yard to get it and see if in deed it has any wires.



    Charles
     
  12. BlueOx

    BlueOx 1/2 ton status

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    Matt,

    I'm sorry to use your post to answer my questions so, I thought I'd help you out. I have been researching the whole TBI swap thing for months and I have collected a binder full of information about it all. I have even gone as far as printing and saving post here on CK5 about the subject. I recently found information on the wiring harness that tells what every wire goes to and what it does. If you would like the info let me know. I can gather it all up and email it to you. WARNING: it will be a big file or a lot of little ones.

    I first found this site (CK5) when I was in the Army I had little questions about the Blazer because it never broke down (knock on wood). I studied every post there was and looked at every link. Learned more about the Blazer in those years then ever. More people on here have helped with my question and or problems than I have expected. Even if its to add humor with the occasional "MAN, that sucks, better you than me!" or the "It sucks to be you!" I would be selfish for me to keep all this info for myself so, if anyone wants it just let me know.


    Charles
     
  13. HarryH3

    HarryH3 1 ton status Author

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    The Air Diverter is only used on vehicles with an air pump. It decides when the air flows into the exhaust manifolds and when it gets diverted into a small muffler that exits to the outside.
     
  14. dyeager535

    dyeager535 1 ton status Premium Member

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    I'm guessing there is an electric cannister purge valve. In with the EGR and both AIR solenoids/switches on the TPI harness is an Electric cannister purge. All 4 of those are tied together in '88 F-body harnesses, so I'd imagine a later truck would have them as well.

    All 4 of those components seem to be little more than on/off, and likely not monitored by the ECM, EXCEPT the EGR. (which I will run) I'm going to leave the wires in place, and see what happens. I don't have AIR or Evap, so I won't be running them anyway.

    I asked on thirdgen.org about removing the cannister/AIR wiring, but didn't get a concrete answer whether the ECM is actually monitoring those, or *just* grounds the circuit, as the wiring diagram shows.

    I'm just going to have to wait and see. I really doubt any of those but EGR is something the ECM will notice that they are missing.

    Hope this helps in some small way.
     
  15. K5 NUTT

    K5 NUTT 1/2 ton status

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    Ahhh..thats it...i thought you were saying on top of the charcoal cannister...which they did do on GM cars in the 80's...my howell harness came with that plug...but i did not run air pump along with the associated diverter valve..just wire ty it to the main trunk near the tps...

    Azblazer
     

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