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Thread: 1987 big block

  1. #1
    Fuel Injected!
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    1987 big block

    1987 3/4 ton suburban 454 TBI
    7747 ecm
    Do yall think I can tune any power or mpg out of the factory tune on this vehicle.if so would I start with timing table.
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    Last edited by mdj; 04-19-2014 at 01:20 AM.

  2. #2
    Fuel Injected!
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    Well I guess I will jump in and find out.

  3. #3
    Fuel Injected!
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    Quote Originally Posted by mdj View Post
    1987 3/4 ton suburban 454 TBI
    7747 ecm
    Do yall think I can tune any power or mpg out of the factory tune on this vehicle.if so would I start with timing table.
    First thing to do would be look at some datalogs to see what the fuel trims are doing and adjust the VE table. Then you should work on the timing. The early factory TBI big blocks did not use a knock sensor and therefore the timing advance is very conservative.

  4. #4
    RIP EagleMark's Avatar
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    There's loads of room in a stock .bin going back in same truck and tone more if the motor is going into something smaller/lighter. These are seriously DE-Tuned. Most don't even have a knock sensor, so timing is not even close.

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
    -= =-

  5. #5
    Fuel Injected!
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    glad to see you back egale mark

  6. #6
    billygraves
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    Quote Originally Posted by mdj View Post
    1987 3/4 ton suburban 454 TBI
    7747 ecm
    Do yall think I can tune any power or mpg out of the factory tune on this vehicle.if so would I start with timing table.
    After you see where you are and get a base cal, then I would start with a visual engine inspect. Clean up the grounds, is the TBI Base gak new? Egr gasket new? What's the pick-up coil look like and the inside fo the dist cap? You runnin the CR43TS a/c plugs( Even though they still have the thin grd electrodes) and gap them @ 0.045" Are the Plug wires apart at 5 and 7 and then 4 & 8? (EMI).

    Then IF the O2 is old or has more than 35k on it, I'd put in a DENSO NEW O2. In a BB if the O2 is in the Ex man, a heated O2 really doesn't help ya that much.

    Personally I would Top Engine Cleaner all the carbon out, especially if you're gonna run the Ign timing up and CR43TS plugs will help.

    Some things to look at and I first suggest you get an A/F Ratio meter and pull the opposite Ex manifold and DRILL/TAP out where the O2 boss is and put in your A/F Ratio O2.
    The Fuel is VERY Rich at WOT for the Cat cooling and your WOT PE you should see this. The idle spds are around 750 If I remember right, try 550. Then try to take the Ign timing up some.
    This should help the MPG somewhat IF YOU KEEP YOUR FOOT OUT OF IT.
    Another thing that will help the MPG is putting in a 4L80-E Use the 1997 up. It has what is called Center Lube and it helped gain 1MPG. It all helps...
    That should get your started and keep you into it for a while. Best of Luck to you and have fun. There is a WEALTH OF KNOWLEDGE HERE!!!!

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