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Thread: Fuel Delivery Help

  1. #1
    Fuel Injected!
    Join Date
    Apr 2015
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    36

    Fuel Delivery Help

    1st Problem, I bought injectors ( GP Sorensen # 800-1807n ) cant find the flow rate on them. Called GP Sorensen and they told me that they did not make these injectors for ten years, no help.
    2nd Problem, I was running out of VE table tuning so i increased the fuel pressure from 15 to 18.
    3rd Problem, Now on cold start open loop I am getting lean surge. Attached is a short log, bin, and ADX files.
    Attached Files Attached Files
    1993 Chevy Blazer TBI Vortec long block 5.7
    16168625 BDJZ 46mm TB 15 PSI fuel
    Camshaft, Hydraulic Roller Tappet, Advertised Duration 288/308, Lift .431/.451
    Chevrolet Performance Vortec TBI Intake Manifold
    shorty's, y-pipe and 3" full boar muffler

  2. #2
    Fuel Injected! sturgillbd's Avatar
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    Jun 2012
    Location
    Big Stone Gap, VA
    Age
    44
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    439
    1. Looking at this post on Thirdgen from our own Fast355, you have 61lb/hr injectors. https://www.thirdgen.org/forums/tbi/...injectors.html
    2. Are you running out of fuel now with the pressure at 18? Injector constant should be around 72-75 instead of 64 in the bin for 18 lbs of fuel pressure.
    3. Look at your idle VE table around idle. I'm going to attach a screenshot of the graphical representation. There is a hole in the area around idle. The fuel is calculated from adjacent cells all around the current point and there are large jumps in fueling around idle. You are going to have to smooth the VE table.
    Attached Images Attached Images
    Last edited by sturgillbd; 05-30-2018 at 05:48 PM.

  3. #3
    Fuel Injected!
    Join Date
    Apr 2015
    Posts
    36
    Thanks You
    I was going to mention that hole, that hole is also in the off idle as well. I will try.
    1993 Chevy Blazer TBI Vortec long block 5.7
    16168625 BDJZ 46mm TB 15 PSI fuel
    Camshaft, Hydraulic Roller Tappet, Advertised Duration 288/308, Lift .431/.451
    Chevrolet Performance Vortec TBI Intake Manifold
    shorty's, y-pipe and 3" full boar muffler

  4. #4
    Administrator
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    May 2011
    Location
    Lakes Region, NH
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    2,901
    According to my GP Sorensen catalog they appear to be stock replacements for 350 TBI injectors for 5.7 engines including the following:

    90-93 Chevrolet B body cars.
    92-93 Buick
    90-93 Cadillac
    87-95 Trucks

    I have catalogs for Sorensen, Standard, and Carquest. Practically speaking this is the same injector as Standard / Carquest TJ7.
    https://www.rockauto.com/en/moreinfo.php?pk=47698&jsn=8

    https://www.ebay.com/itm/Fuel-Inject...wAAOSwX8da2S9v

    https://www.techsupportforum.com/for...le-122129.html

    If you are simply setting up an initial calibration I recommend beginning with values from a 5.7 Caprice calibration then modifying them as needed.

  5. #5
    Fuel Injected!
    Join Date
    Apr 2015
    Posts
    36
    That was the fix, I set the injector constant to 72 and went back to the bin file I got from Dave and copied over the VE tables. I will see how tuning goes.
    Thanks again sturgillbd
    1993 Chevy Blazer TBI Vortec long block 5.7
    16168625 BDJZ 46mm TB 15 PSI fuel
    Camshaft, Hydraulic Roller Tappet, Advertised Duration 288/308, Lift .431/.451
    Chevrolet Performance Vortec TBI Intake Manifold
    shorty's, y-pipe and 3" full boar muffler

  6. #6
    Fuel Injected!
    Join Date
    Apr 2015
    Posts
    36
    Up date. Injector DC% seems low, at 30% throttle DC% is at 11.84 injector Base Pulse Width 2.90.
    I don't know how to address this, if this is even a problem, truck runs OK just cant seem to tune it.
    1993 Chevy Blazer TBI Vortec long block 5.7
    16168625 BDJZ 46mm TB 15 PSI fuel
    Camshaft, Hydraulic Roller Tappet, Advertised Duration 288/308, Lift .431/.451
    Chevrolet Performance Vortec TBI Intake Manifold
    shorty's, y-pipe and 3" full boar muffler

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