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Thread: Help adjusting lean condition - 5.3L M122

  1. #1
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    Help adjusting lean condition - 5.3L M122

    Hey guys,

    Looking for a little help on where to look for some basic startup info for a modified 5.3L LS. Here is the engine configuration:

    2001 Gen III 5.3L V8
    Heads GM 706
    Lifters Summit Racing? Performance LS7 Hydraulic Lifters SUM-HT215-16
    Intake Holley Lo-Ram
    Supercharger M122 Eaton - GT500 (2.0L Displacement) 2.5" pulley
    Blower Adapter Tom Demeuse Engineering
    Cam BTR Truck Norris 212/22X .552"/.552" 107 LSA
    Cam accessories Beehive springs, hat seals and 7.400" long, 5/16" Chromoly Pushrods with .080" wall thickness.
    Rocker arm kit Brian Tooley Racing BTR LS Rocker Arm Trunion Kit - 4.8 5.3 5.7 6.0 6.2 LS1 LS3 LQ4 LM7 LM4 Trunnion Set
    Stock lower end Stock - Rings only(gapped)
    spark plugs NGK Standard Series Spark Plugs for 1991-1992 XJS - BR7EF
    Exhaust manifolds Hooker LS Cast Iron Exhaust Manifolds 8501-3HKR
    Accessories Holley Mid-Mount Complete Accessory Systems 20-185BK
    Rings Sealed Power Performance Piston Ring Sets E937K
    Oil pump Melling Performance Oil Pumps 10296
    Oil Pan Holley Retrofit Engine Oil Pans for GM LS Engines 302-2
    Fuel Injectors 65lb DeatschWerks - 16U-00-0065-8 (USE LS1 table)
    Fuel Pump Camaro SS Fuel pump 58psi internally regulated
    Cam Sensor GM 19420911
    Crank Sensor Delphi SS10206
    Knock Sensor GM 2133521
    Coolant Temp Sensor AC Delco 2134514
    Transmission Gearstar 4L80E III


    Current situation - The engine is running with a base tune simply updating the fuel injector info and turning off the unneccesary emmissions sensors. I have exhaust that is newly installed. O2 sensors are reading now and I will be taking it to be tuned on a dyno as the next step. I'd like to address a couple related concerns before trailoring it to the tune shop. 1. The engine is running using the stock MAF sensor and updated info on the injectors, however I can't get it to idle down below 1100-1200rpm. Also, the engine is running lean. Where should I got to get some help to correct the lean condition and address the idle issue so that it's easier to move around the shop and load onto a trailer? 1963 chevy truck Ryan GStar.hpt25-07-05 15-06-55.hpl

  2. #2
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    It appears you have a vacuum leak or the throttle body is open to far or the blower bypass isnt adjusted corretly.
    I see your still using the factory 1 bar map. You will need a 2 bar map at minimum.

    To richen the fuel mixture you will need to add fuel to the VE table and MAF.
    But i would start by just getting a 2 bar map and have the VE table mostly sorted out.

    Since its a M122 blower i wouldnt even run a MAF.

  3. #3
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    Quote Originally Posted by RDF1 View Post
    It appears you have a vacuum leak or the throttle body is open to far or the blower bypass isnt adjusted corretly.
    I see your still using the factory 1 bar map. You will need a 2 bar map at minimum.

    To richen the fuel mixture you will need to add fuel to the VE table and MAF.
    But i would start by just getting a 2 bar map and have the VE table mostly sorted out.

    Since its a M122 blower i wouldnt even run a MAF.
    Thanks RDF1. I found a leak after your response. I had a vacuum line cap on the blower that had a tear in it. I also connected the boost bypass line to the vacuum reference. Here is an updated log. Idles much better, but still a little high. STFT looks like it's really lean. I haven't done anything with the VE tables yet. Any tutorials out there for that? Unlike most applications I really wasn't after maximum boost. This is in a classic C10 pickup, so my intent was just to pickup a few horsepower but not go crazy. I'd like to run pump gas most of the time, so I was hoping to keep the boost down low enough that I could still run the MAF. That may not make sense, so I'll just have to see how much boost it's making. It's got a 3" pulley on the supercharger...I intentionally didn't go as small as I could to keep from making too much boost.
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    Last edited by 63chevytuner; 1 Day Ago at 07:57 PM.

  4. #4
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    You still have too much airflow into the engine.

    Add IAC Position and MAF Hertz to the channels.

    No point in doing anything until you get the vacuum leaks fixed.
    What throttle body do you have?
    And do you have the IAT sensor after the blower?
    Are you running 93 octane?

    Pump gas wont be a issue but having the proper tune will make or break the setup.

    You can run the MAF if you want, was just saying you wont need it.

    Will also need a 2 bar map tho before doing anything else.


    Once you get the vacuum leak issue sorted out the Trims might get better. Then you can start tuning.

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    Quote Originally Posted by RDF1 View Post
    You still have too much airflow into the engine.

    Add IAC Position and MAF Hertz to the channels.

    No point in doing anything until you get the vacuum leaks fixed.
    What throttle body do you have?
    And do you have the IAT sensor after the blower?
    Are you running 93 octane?

    Pump gas wont be a issue but having the proper tune will make or break the setup.

    You can run the MAF if you want, was just saying you wont need it.

    Will also need a 2 bar map tho before doing anything else.


    Once you get the vacuum leak issue sorted out the Trims might get better. Then you can start tuning.

    Thanks! I do have an IAT after the blower. I am running 91 octane right now, but can run 93 normally. I did another more detailed leak check using a pressurized smoke method diag tool. I've got a seal missing at my throttle body. The throttle body is a 102mm throttle body that Tom Demuese sent me with the blower adapter/intercooler. I have a 2 bar map sensor and I'll install it and update the tune.
    Last edited by 63chevytuner; 23 Hours Ago at 03:17 PM.

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    The only leak I can find now is the shaft seal on the throttle body is missing. See the picture. I'm assuming there is intended to be a seal there anyway. It's leaking a good amount, but I don't remember seeing a seal here when I got the throttle body. It's up under where the return spring sits.
    Attached Images Attached Images
    Last edited by 63chevytuner; 23 Hours Ago at 03:18 PM.

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    That looks like a cheap Chinese throttle body.
    When it was idling, was the idle set screw adjusted all the way out to close the TB?

    What is the PN on the 2 bar map?

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    Quote Originally Posted by RDF1 View Post
    That looks like a cheap Chinese throttle body.
    When it was idling, was the idle set screw adjusted all the way out to close the TB?

    What is the PN on the 2 bar map?
    I'll get the map sensor part number. It may actually be a 3 bar, let me check. I may need to replace the throttle body. To your point, I'm not sure exactly what brand it is. What would you suggest for a 102mm?

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    Quote Originally Posted by RDF1 View Post
    Agreed Nick Williams stuff is nice. A little pricey but nice. Have you heard any reviews on the Summit or Jegs branded 102mm throttle bodys? This will be a fun cruiser, but not anything at the race track.

    Summit Racing SUM-227102B - Summit Racing? Billet Throttle Bodies
    Attached Images Attached Images

  11. #11
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    Quote Originally Posted by 63chevytuner View Post
    This will be a fun cruiser
    put the stock t body back on

  12. #12
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    Quote Originally Posted by 63chevytuner View Post
    Agreed Nick Williams stuff is nice. A little pricey but nice. Have you heard any reviews on the Summit or Jegs branded 102mm throttle bodys? This will be a fun cruiser, but not anything at the race track.

    Summit Racing SUM-227102B - Summit Racing? Billet Throttle Bodies
    They are chinese made as well.
    Stick with stock or nick williams.