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Thread: LQ4 into a 1984 G30 Chassis

  1. #1
    Join Date
    Jul 2006
    Posts
    10
    Hi,

    I just bought an Vortec 6000 (LQ4) with a 4L80E trans to swap into my motorhome (1984 Chevy G30 chassis). I got the engine harness, PCM, sensors, ETC, TAC, gas pedal, engine accessories, etc... from a 2006 Express van.

    The thing I didn't get was the instrument cluster. Am I going to need the cluster to make this swap work easier? Is there anything else I forgot? I'm trying to make the swap as "bolt-in" as possible and hopefully I can avoid any PCM reprogramming.

    I've read the others have had to have their PCM reprogrammed to disable the VATS. Is there any other way around this?

    Has anyone else swapped one of these engines into a 80's van chassis? Are there any mechanical issues I should watch out for besides the motor mounts? I'm assuming it will fit since a 454 will fit.

    Are there any Chevy/GM publications that would be helpful for making this swap?

    Thanks,
    Jay

  2. #2
    Join Date
    Oct 2005
    Location
    Baton Rouge, LA
    Posts
    997
    Ooo wee! I can't say this has been done in a motorhome, but won't say it cannot.

    To start... you don't necessarily NEED the stock instrument cluster from the new vehicles. If you can fab one in your current dash, that'd be cool to see. You'll need the harness for the dash stuff tho. Autometer (and other vendors) sell all electric gauges that'll work with these motors. Easy pickins!

    As for the VATS... there's a way around it, as long as you disable it (or have a tuner disable it) within the PCM. Otherwise, you'd have to have the in-dash harness, complete with all stock components (i.e. BCM, etc) to form a closed loop system (unusual & not the best route). VATS can be disabled with tuner software packages like HPTuners, EFILive, etc.

    Good luck, ask questions, and posts pics!
    Test-n-Tune (Nov 23, 2008) - 13.65s @ 98mph

  3. #3
    Join Date
    Jul 2006
    Posts
    10
    When you say that I'll "need the harness for the dash stuff" do you mean that the engine won't run without the dash harness, or it won't run without the guages, or I just won't have any guages?

  4. #4
    Join Date
    May 2004
    Posts
    2,120
    Hi Jay, You should be able to use your stock guages. I don't think it would be any easier installing the newer one's but that's JMHO. What you need to do is try to get a wiring schematic or try tracing out and marking your wires. From there you can decide what you need to tie into the harness and what will be standalone with your existing wiring.

    Here's a couple of things to think about:
    Electric fuel pump and relay
    TCC to brake switch
    VSS (speed sensor) input to gauge
    Tach tie in
    A/C request and relay
    A/C clutch engage
    Cooling fans and relays or optional fan clutch
    Cruise control
    Starter wiring relay
    MIL indicator
    Altenator
    Neutral Safety switch
    Serial data connector and wiring

    You can use the wiring harness that came with the motor or get Allen to build you one.


    97 GMC, 2002 LS6.

    1991 GMC Syclone #1428

  5. #5
    Join Date
    Nov 2003
    Location
    Denton Texas
    Posts
    20,540
    The engine will run without any gauges attached.
    See my truck data in the "My Garage" section here... http://www.ls1truck.com/forums/my-ga...tml#post191709

  6. #6
    Join Date
    Jul 2006
    Posts
    10
    Thanks for all of you replies. It looks like I need to get some wiring diagrams. What is a good source for these?

    Does anyone know if I need a separate harness for the ETC?

    Thanks,
    Jay

  7. #7
    Join Date
    Nov 2003
    Location
    Denton Texas
    Posts
    20,540
    You can subscribe to www.alldatadiy.com for about $15 a year to get all the information you need.
    See my truck data in the "My Garage" section here... http://www.ls1truck.com/forums/my-ga...tml#post191709

  8. #8
    Join Date
    Oct 2005
    Location
    Baton Rouge, LA
    Posts
    997
    <div class='quotetop'>QUOTE(RedHeartbeat &#064; Jul 14 2006, 05&#58;58 PM) [snapback]58108[/snapback]</div>
    You can subscribe to www.alldatadiy.com for about &#036;15 a year to get all the information you need.
    [/b]
    &#036;25 for first-timers (online). Not sure how much Autozone charges for in-store signups.

    <div class='quotetop'>QUOTE(Jay &#064; Jul 13 2006, 08&#58;06 PM) [snapback]58012[/snapback]</div>
    When you say that I&#39;ll "need the harness for the dash stuff" do you mean that the engine won&#39;t run without the dash harness, or it won&#39;t run without the guages, or I just won&#39;t have any guages?
    [/b]
    What I meant is if you don&#39;t have a tuner package to mod the PCM, you&#39;d have to have all the components of a stock setup in order to start/run the engine. A tuner package, like HPT, can disable options like VATS that will prevent starting/running the engine without receiving a signal from the BCM (a part of the in-dash harness). If you have something like that, no in-dash harnesses are required. You&#39;ll need a Class-2 data comm connector in order to connect an OBDII connector to, in order to scan/write using tuner packages.

    Hope I didn&#39;t confuse you. Just keep asking questions. Everyone here is good about suggestions & helping.
    Test-n-Tune (Nov 23, 2008) - 13.65s @ 98mph

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