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TBI Swap???

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by outlaw612, Jan 21, 2002.

  1. outlaw612

    outlaw612 1/2 ton status

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    I did a search and couldnt find what I wanted. I would like to find a list of all the parts needed to swap my carb out for a TBI setup. Im looking at a couple of different people with this for sale, but want to be sure they have everything.
    Has anyone done a write-up on this?

    Also, will the TBI swap directly to an older motor? I think I recall hearing of problems with the intake bolt patterns? If this is the case, can I swap a set of Vortechs and then will it work?

    Thanks for the help.

    <a target="_blank" href=http://www.geocities.com/outlaw613/K5.html>http://www.geocities.com/outlaw613/K5.html</a>
     
  2. KRAZIE87K5

    KRAZIE87K5 1/2 ton status

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    Sup Matt! Have you seen the latest Four Wheeler? They are praising a new Edelbrock QJET as the best carb out there, and that it could be better than Fuel Injection. Its on page 98... the 1910 series carb. "Willy Worthy" wrote the article, and says that he may ditch plans of installing fuel injection on his rig, and install this carb on his 383 SBC engine! I think it might be worth looking into... [​IMG]

    <font color=red>GOT MUD???</font color=red>
    My license plate reads:<font color=blue> 8 YR SUV</font color=blue>
    454/TH400/NP205 - 14BFF/D60/w/ 4.10s - 36" TSLs
     
  3. rocnwilly

    rocnwilly 1/2 ton status

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    You can check out Turbo City site they have a good description of all the parts needed. HP books also has a TBI swap book. As for the intake you can run your stock intake with an adapter to mount the TB. I will be doing the same thing soon. I will let you know how it goes. I have a complete unit from a 1990 Chevy Camaro, but I do not know all the names of the components.
     
  4. BurbinOR

    BurbinOR 3/4 ton status

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    Check these sites out..........

    www.fuelinjection.com
    www.jmsperformance.com
    '79 ONE TON TPI K5 - See it at---&gt;<a target="_blank" href=http://www.blazzinor.rockcrawler.com/>BlazzinOR's Beast Buildup
     
  5. azblazor

    azblazor 1/2 ton status Premium Member

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    We are in the process of completing this swap. We are installing on a 77 400SBC. We bought a 89 TBI setup from a wrecker $300. It had:
    the basic wiring harness, w/ fuel pmp relay and fuse,
    the computer,
    manifold,(drilled and reshaped middle 4 mounting holes)
    TBI unit (carb),
    Distributor, coil
    stuff from the top of the manifold, MAP, ESC, EGR solenoid,
    knock sensor

    We also have a 87 K5 donor vehicle in back. We didn't want to remove too much from this truck as it's got to go back together.
    Extra things we had to get from returning to wrecker or from the 87 in back:
    O2 sensor (new) $30
    In line fuel Pmp Holly $120
    Fuel fittings for the TBI fuel in and out, (we cut lines for the fittings)
    Exhaust manifolds (O2 sensor screws in, we could have welded in a bung somewhere in the old system)
    Misc vacuum lines to connect EGR, Pwr brake booster, etc.
    The connector to interface with the computer under the dash -C373/C374 and the ALDL connector,
    Plugs and wires
    Manifold bracket for the 700R4 (also swapping in) TV cable and throttle cable.

    Actual wiring interface involved:
    underhood - hook up connectors, knock, iac, tps, esc, egr solenoid, water temp, oil (t'ed into old sender fitting), O2, am I forgetting any ? :-)

    splicing the pink ignition wire to the new distributor connector,

    jumper hot wire from exisitng 77 firewall power terminal block to the new 89 firewall power distribution block,

    wire fuel pump up (2 wires)

    underdash -
    wire ALDL to C373/374(interface connector to the ECM),

    additional inputs to C373/374:

    brake switch power (opens when braking) to computer (TCC)
    - used the old contacts from cruise control brake sw contacts.

    pink and red (hot in run or start) to power up computer, from fuse box

    ground wire

    With this wiring we cranked it up after tweaking the distributor a couple of times. Actually runs really well. Still really rough at first, but smooths out to a pretty good idle after a couple of minutes. We are working on that. Timing and idle adjustment.

    The trany we put in apparently has no 3rd or 4th at all - so we could not check if the lock up worked - or how well our TV cable was adjusted for the 700r4.

    ISSUES I need a little help on:
    Park neutral input to computer c373/374 connector - how has any body else done this? My switch on the column only interrupts main power to starter - has no other contacts??

    Speed signal to computer c373/374 connector - necessary?? bring from what or where?

    Wiring harnes was from 89 2WD - the wiring harness has connector for what could be a VSS signal from the transmission ....only the colors don't match to the 89 diagram...a confusion point. Will it be OK to splice the connector that fits the NP208 connector in, and connect it to the transfer case??? Is it the same Vss processing point for the computer????? Doug (AZBLAZER) - need some help here!

    Thanks
    Mark


    <font color=blue>azblazor</font color=blue>
    <font color=orange> 79 K5 454-FI / 4L80E, NP205, D60, FF14, 4" lift, 9K Warn </font color=orange><P ID="edit"><FONT class="small">Edited by azblazor on 01/24/02 09:39 PM.</FONT></P>
     
  6. azblazor

    azblazor 1/2 ton status Premium Member

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    Calling TBI gurus

    <font color=blue>azblazor</font color=blue>
    <font color=orange> 79 K5 454-FI / 4L80E, NP205, D60, FF14, 4" lift, 9K Warn </font color=orange>
     
  7. pcorssmit

    pcorssmit 1/2 ton status

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    <blockquote><font class="small">In reply to:</font><hr>

    Park neutral input to computer c373/374 connector - how has any body else done this? My switch on the column only interrupts main power to starter - has no other contacts??

    <hr></blockquote>

    I just recently fixed this on mine. (W/out it, the engine stumbles a bit when put in gear, especially when cold. The idle jumps up a bit too when going from forward to reverse (or vise-versa) if done too slowly, ie hard on the trans.) The switch is the same. The TBI trucks don't have the electrical interupt for the starter, it is redundant since the mechanical linkage prevents the key from turning to start unless it is in P or N. Just cut the connector off, and solder the Yellow and Purple wires together (~ 12 gauge).

    <blockquote><font class="small">In reply to:</font><hr>

    Speed signal to computer c373/374 connector - necessary?? bring from what or where?

    <hr></blockquote>

    There has been a lot of talk on this lately. Easiest/Cheapest way would be to get a speedo from an ~82-'89 that has the VSS provisions, and the VSS. The disadvantage of this method is that your ODO would be off, and the font on the gauges may not match (I forget what year it changed, but I think '77 is the newer type). Alternatly, you could try to retrofit/modify your existing speedo to work (this is what we're gonna try on my brother's '70). Or, you could buy an aftermarket style that goes inline in the speedo cable.

    <blockquote><font class="small">In reply to:</font><hr>

    Wiring harnes was from 89 2WD - the wiring harness has connector for what could be a VSS signal from the transmission ....only the colors don't match to the 89 diagram...a confusion point. Will it be OK to splice the connector that fits the NP208 connector in, and connect it to the transfer case??? Is it the same Vss processing point for the computer?????

    <hr></blockquote>

    I'm a little confused here. The VSS signal goes to the computer through one of the pins on the 6 pin connector near the computer (I'm guessing this is what you are calling the c373/374 connector). There is also a ground and a hot wire that go to the VSS. The only electrical connector on the 208 is for the 4wd indicator light (earlier 700 equiped trucks also used a relay to prevent 3rd gear TCC lockup in 4wd, but the TBI trucks don't). I do recall there was a discrepancy on the color of one of the wires on the 6 pin connector, my diagram is for an '88, but the '87, '88, and '89 harnesses I have match eachother but not the diagram. Will check which wire it is when I get home tonight (I made a note in the book). (It could be that the '89 2wd used an electronic speedo, I don't know. (I may have an '89 book, I'll take a look) I know for a fact that '89 2wd used a cable driven speedo.)

    Pete

    '83 K5, 350 TBI (ex 6.2), 700R4, NP208, Dana 60/14 bolt, 4.56s, Detroits, 3" lift, 15-39.5x15 TSLs
    '97 Dodge 2500 4x4 CC LB Sport, Cummins 5 spd
     
  8. outlaw612

    outlaw612 1/2 ton status

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    Thanks everyone for the info. Looks like Ive got some more reading to do. I am definately interested in the new carb(ease of install compared to the TBI).

    Thanks Again.

    <a target="_blank" href=http://www.geocities.com/outlaw613/K5.html>http://www.geocities.com/outlaw613/K5.html</a>
     
  9. pcorssmit

    pcorssmit 1/2 ton status

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    OK, the wire that was called out as the wrong color was the P/N switch wire. The book says brn/blk, but the wire is orn/blk. (pin B10 on the computer, and pin F on the 6 pin connector).

    Pete

    '83 K5, 350 TBI (ex 6.2), 700R4, NP208, Dana 60/14 bolt, 4.56s, Detroits, 3" lift, 15-39.5x15 TSLs
    '97 Dodge 2500 4x4 CC LB Sport, Cummins 5 spd
     
  10. pcorssmit

    pcorssmit 1/2 ton status

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    Carbs are for lawn mowers. [​IMG]

    Pete

    '83 K5, 350 TBI (ex 6.2), 700R4, NP208, Dana 60/14 bolt, 4.56s, Detroits, 3" lift, 15-39.5x15 TSLs
    '97 Dodge 2500 4x4 CC LB Sport, Cummins 5 spd
     
  11. outlaw612

    outlaw612 1/2 ton status

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    I agree, but going by the replies here and the post by AZBLAZER, I can see I havent done enough research on this . Does anyone know the name or place where I can find a TBI swappers guide. Ive heard of it before, but dont know where to find it.
    Thanks everyone for the info


    <a target="_blank" href=http://www.geocities.com/outlaw613/K5.html>http://www.geocities.com/outlaw613/K5.html</a>
     
  12. ftn96

    ftn96 1/2 ton status

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    Amen brother!

    Still trying to figure out why they have brail on drive thru ATM's?? [​IMG]
    <a target="_blank" href=http://www.mccords.s5.com/myk5/index.htm>NashvilleK5</a>
     
  13. RootBreaker

    RootBreaker 3/4 ton status Premium Member

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    I have a TBI 1991 Police 9C1 police motor going into my truck....everyone told me to goto tbi but I gotta say... My truck is stupid so lets keep it that way... and reading above it is a bigger chore than I thought... Hope it all works out for ya...
    my $.02


    1978 Chevy 3/4 - 14" leafs -dana 44w/4.56's -14 bolt corp w/4.56's on 40x17x16.5 Ground Hawgs on 16.5x12 steel rims-NP205&SMC465
     
  14. azblazor

    azblazor 1/2 ton status Premium Member

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    Pete,
    Thanks for the response. It helped a lot. I'll wire the park/neutral wire through my steering shaft switch, after removing and jumpering the starter/coil wires.

    The "speed signal" is still somewhat confusing to me. I guess because I still need to understand what it does in the computer.

    In the 1989 Wiring Diagnostic diagrams, there is clearly shown a "transfer case speed sensor" with 2 wires. One labled "Hi" is ckt 400 and yellow, the other is "LO" and is ckt 401 and purple/white strip or just purple depending on which page you look at. My 89 wiring harness has a connector in the transmission loom that has a weather pak connector with a yellow and a purple/white strip or a Brown/white stripe wire in it. But the connector does not fit the connector on the top of my 87 NP208 transfer case. The 89 Wiring diagnostic diagrams show This "speed signal" inputing to the I/P cluster as ckt 400 and 401. The 437 (brown) circuit which actually goes into the computer seems to originate in the Cruise Module, it then makes it way to the I/P cluster as "437 A" and comes out as "437 B" and goes to the ECM through the C373 connector.

    The 87 transmission wiring loom has a connector which fits the 87 Transfer case and it has 2 wires which are Purple and Tan/white. The 87 Wiring Diagrams show a "Speed Sensor" with three wires. It is not clear at all where it is. One of the wires in this 3 wire switch, is the brown circuit 437 wire. It apparently goes directly to the ECM through a connector.

    I'm willing to accept that the transfer case does not originate the brown (circuit 437) wire speed signal. But I am confused about what this circuit 400 and 401 do in the 89 C\K truck.

    And, where is the "speed sensor" with three wires on the 87 Blazer??

    So.........I understand that I most likely will need to get the box that goes in line with the speedo cable. Does it go under the dash? Then I will route that signal to the ECM on the Brown wire circuit 437?

    Anybody got a simple answer for what the brown 437 circuit does for the computer?

    Thanks Pete and anybody else who has input.

    Mark



    <font color=blue>azblazor</font color=blue>
    <font color=orange> 79 K5 454-FI / 4L80E, NP205, D60, FF14, 4" lift, 9K Warn </font color=orange>
     
  15. BurbinOR

    BurbinOR 3/4 ton status

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    Three books are good reading and are available from <font color=blue> ONE TON</font color=blue> <font color=green>TPI'd</font color=green><font color=red> BEAST<font color=red>[/b]
     
  16. outlaw612

    outlaw612 1/2 ton status

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    Thanks for the info. Ill check into the books.

    <a target="_blank" href=http://www.geocities.com/outlaw613/K5.html>http://www.geocities.com/outlaw613/K5.html</a>
     
  17. azblazor

    azblazor 1/2 ton status Premium Member

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    OK, here is what "Chevrolet TPI &amp; TBI Engine Swapping" says:
    Regarding the P/N switch:
    Some wiring harnesses ground the Park/Neutral wire so that the ECM always thinks the vehicle is in Neutral or Park. The reason is to prevent the SES (service engine soon) or Check engine light from being turned on due to lack of a VSS signal. The service manual states: The ECM uses the P/N signal as one of the inputs to control: Idle Air control; VSS diagnostics; EGR. If the P/N wire is grounded in drive, the EGR would be inoperative , resulting in possible detonation.
    Without the P/N switch conected (grounded) the engine will run ok but engine speed may drop excessively when shifting into gear.

    Regarding the VSS:
    The VSS tells the ECM how fast the vehicle is going. Most people think the VSS is only used for for the lock-up torque convertor. The VSS is also used to control the EGR valve, the charcoal canister purge valve, the electric cooling fans, idle speed, and air/fuel ratio.
    It must be emphasized that the VSS is used to control the idle speed when the vehicle is moving. Without the VSS the vehicle may have stalling problems under certain conditions. The reason an engine not equipped with VSS may stall is because when the ECM has the signals that indicate the engine should be idling (foot off gas, vehicle moving less than 2 MPH), idle speed is closed loop ( which is not the same as the O2 sensor running closed loop) and the ECM will try to maintain a programmed idle speed. If the vehicle is moving, the ECM opens the IAC (idle air control) a programmed amount, regardless of engine speed, which is usually a position that will make the engine idle about 50-100 RPM above the programmed idle speed. Stalling can occur when the vehicle is in the over-run condition (foot off gas- engine speed above the programmed idle speed) because the ECM will try to lower the idle speed to the stationary programmed speed. The IAC may not be able to open rapidly enough to prevent the engine from stalling.
    Raising the minimum idle speed with the adjusting screw can eliminate stalling, but the engine will not run optimally without a VSS. Some Chevrolet engines are programmed to run lean under highway mode. Without VSS the ECM will not get the signals to run the engine for best fuel economy. There are a lot of other programs in the ECM which depend on the VSS.

    This answers my question. I hope it clarifies it for any other people who wanted to know.
    Mark


    <font color=blue>azblazor</font color=blue>
    <font color=orange> 79 K5 454-FI / 4L80E, NP205, D60, FF14, 4" lift, 9K Warn </font color=orange>
     

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