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Thread: Throttle body boring and bushing

  1. #1
    Fuel Injected! brian617's Avatar
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    Throttle body boring and bushing

    Best place to get TBI bored, and bushed?
    89 K1500 Scottsdale 5.7L 5spd 3:42 RamJet cam Dart iron TBI heads 427 PCM swap
    95 C2500 Cheyenne 6.5L turbo diesel 4L80e 4:10 DB2-4911 Manual pump conversion 0411 PCM trans control 2Bar COS
    05 Outback XT 2.5L turbo gas auto

  2. #2
    Super Moderator dave w's Avatar
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    Quote Originally Posted by brian617 View Post
    Best place to get TBI bored, and bushed?
    I'll recommend, http://www.rvmorsemachine.com/

    dave w

  3. #3
    RIP EagleMark's Avatar
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    They have a great reputation along with great prices. While your looking there the fuel pressure gauge adapter is the best one made and if you look close at the gauge it is a Marshall liquid filled and top of the line stuff!

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

  4. #4
    Fuel Injected! brian617's Avatar
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    Thats the direction I was leaning, just curious if anyone associated with this forum did them. Hoping this cures my idle hunt/surge. Cant imagine how many times the throttle blades have been opened and closed on an 89 k1500 with a 5spd
    89 K1500 Scottsdale 5.7L 5spd 3:42 RamJet cam Dart iron TBI heads 427 PCM swap
    95 C2500 Cheyenne 6.5L turbo diesel 4L80e 4:10 DB2-4911 Manual pump conversion 0411 PCM trans control 2Bar COS
    05 Outback XT 2.5L turbo gas auto

  5. #5
    RIP EagleMark's Avatar
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    Your right about the 5 speed, all manual trans TBI units do wear much faster then autos.

    You can use a propane torch to spray gas around and look for the vacuum leaks.

    Did you ever post a log with said idle surge? IAC counts low?

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

  6. #6
    Fuel Injected! brian617's Avatar
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    I did post one and you were generous enough to make some changes to my .BIN. However the problem still existed and I was getting frustrated. I kept pulling my VE table down further and further trying to get my idle BLMs on a hot engine sorted out. I was pulling out so much VE that my cold starts where terrible. I adjusted the Open loop AFR tables with no results. Finally I started getting driveability issues as well. I then switched to a $0E manual .BIN and started fiddling with it. Right away it ran much better and the manual trans driveability was so much better. Once again in my hunt for VE perfection I'm back with a cold start surge and even some on a hot engine. I'm closer this time with my VE table and the surge is not quite as pronounced, but I'm leaning toward a mechanical ie vacuum leak. The only other thing running around in my head is the fact i'm running 17.5 psi of fuel pressure and maybe that is too much to tune idle, even though my VE table has some mid 90s in it. The truck runs very well and starts good with the idle VE cells closer to stock but the BLM will drop down close to 100 hot idle. I read the Asynch vs Synch thread today hoping my answer was in there, but it seams as if my .BIN is already enabled for synch idle. So instead of chasing my tale, I thought i might try to remeady the worn TBI and see where that gets me. There is some hope that keeps me going, the rest of my BLMs are coming together nicely and I can feel the difference
    89 K1500 Scottsdale 5.7L 5spd 3:42 RamJet cam Dart iron TBI heads 427 PCM swap
    95 C2500 Cheyenne 6.5L turbo diesel 4L80e 4:10 DB2-4911 Manual pump conversion 0411 PCM trans control 2Bar COS
    05 Outback XT 2.5L turbo gas auto

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    RIP EagleMark's Avatar
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    The propane torch gas can be pointed at all the right spots while engine is warmed up and idling, if it finds a vacuum leak the idle will raise... When you put the new TB on have a spare set of injectors serviced at Mr Injector ready to go as well.

    Can you raise idle by 100 RPM for now to see if it helps?

    Have you moved the O2 sensor from stock location?

    Have your reduced Proportional gains?

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

  8. #8
    Fuel Injected! brian617's Avatar
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    I've raised idle, lowered idle (to get more BLM data) and then raised it back again. Better at higher idle but not cured.

    Here is our o2 discussion. http://www.gearhead-efi.com/Fuel-Inj...M-advice/page2 post 21 down.

    Haven't messed with prop gains... yet LOL!
    89 K1500 Scottsdale 5.7L 5spd 3:42 RamJet cam Dart iron TBI heads 427 PCM swap
    95 C2500 Cheyenne 6.5L turbo diesel 4L80e 4:10 DB2-4911 Manual pump conversion 0411 PCM trans control 2Bar COS
    05 Outback XT 2.5L turbo gas auto

  9. #9
    RIP EagleMark's Avatar
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    Try reducing Prop Gains at idle by 50% and see what happens?

    Your O2 sensor has moved from stock but so has ECM swap and in that new PCM the O2 sensors are usually much furhter back, so should be OK. But can also try to increase "Integrator Delay vs. Airflow" in case the bin you are using just happened to have O2 sensor closer then others. To much just slows INT fueling change and won't hurt. But to little and INT is changing fueling based on wrong part of exhaust gas sampled by O2 sensor. So you get a yo yo effect...

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

  10. #10
    Fuel Injected! brian617's Avatar
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    Will that help open loop where it is most notable?

    What is the computer using to regulate AFRs in open loop?
    Last edited by brian617; 11-09-2013 at 06:04 AM.
    89 K1500 Scottsdale 5.7L 5spd 3:42 RamJet cam Dart iron TBI heads 427 PCM swap
    95 C2500 Cheyenne 6.5L turbo diesel 4L80e 4:10 DB2-4911 Manual pump conversion 0411 PCM trans control 2Bar COS
    05 Outback XT 2.5L turbo gas auto

  11. #11
    RIP EagleMark's Avatar
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    No those are CL issues... Open loop AFR are the tables themselves with no feedback. "Open Loop AFR vs. Temperature vs. Vacuum" and choke...


    I think you have a vacuum leak...

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

  12. #12
    Fuel Injected! brian617's Avatar
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    Quote Originally Posted by EagleMark View Post
    I think you have a vacuum leak...
    Me too. I'll break out the propane torch and see what gives.

    Thanks Mark
    89 K1500 Scottsdale 5.7L 5spd 3:42 RamJet cam Dart iron TBI heads 427 PCM swap
    95 C2500 Cheyenne 6.5L turbo diesel 4L80e 4:10 DB2-4911 Manual pump conversion 0411 PCM trans control 2Bar COS
    05 Outback XT 2.5L turbo gas auto

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