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Thread: When I put it in reverse

  1. #1
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    When I put it in reverse

    Sometimes when I put it in reverse,the idle dips down to around 500rpm,almost wants to stall,then it will finally smooth out.It happens around the end of this scan,when I go to back up my driveway and again when it was just sitting and I was going between drive and reverse. The motor is a 2003 Express Van 6.0L and 4L80E trans. All bone stock.Not a daily driver,just a toy. Running SD with trims off.Tuning off of the wide band. This only happens when I put it in reverse,no other gear,and it is intermittent also. Otherwise how am I doing on the tune? Are the settings on my trans too high? It shifts like a little nudge from a loaded tri axle truck,I LOVE it,wife not so much.I think the VE table is pretty close and I just ordered the cam and springs,so I get to do it all over again soon.All comments welcome.
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  2. #2
    Tuning Addict 5FDP's Avatar
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    Bump the idle rpm 100 and it'll help. You'll be wanting about a 750rpm idle anyway depending on camshaft. Not sure how in depth you really want to go if you are going to have to do idle airflow tuning all over again with the camshaft change. Because then you'll be adjusting the base running airflow and possible the throttle cracker and follower settings.

    Hopefully you bought new injectors too, you won't have enough headroom on the stock ones.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

    If you don't post your tune and logs when you have questions you aren't helping yourself.

  3. #3
    Senior Tuner cobaltssoverbooster's Avatar
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    my bone stock '04 awd 6.0 had a factory idle of like 550 or 600. i lifted mine to 750 and all the weird idle issues i had went away. it also made idle easier to control. wideband cleaned my fuel table up in about 3 drive cycles.
    2000 Ford Mustang - Top Sportsman

  4. #4
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    It was set at 550rpm stock and I bumped it up to 630rpm,it seems odd that it only happen in reverse,will bump it up some more.
    I know my stock injectors are running almost at the limit now,looking for recomenditations on replacement ones.
    New parts going in now
    BTR Stage 2 Turbo, Duration 226/231, Lift .605/.598
    Summit Racing? Pro LS Upgraded Rocker Arms SUM-141556
    Summit Racing? LS Lifter and Guide Kits SUM-HTLSKIT
    Next purchase will be a 3800 stall converter.
    Then will come the turbo.Planning on about 10lb of boost.
    Would flex fuel injectors be enough to feed it? or need bigger?
    What MAP will I need? What are the limits on 2bar and 3bar
    I have bookmarked and been reading everything on how to tune with a cam.

  5. #5
    Tuning Addict 5FDP's Avatar
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    If you went turbo, go with much larger injectors. Something like 60-80lb/hr at a minimum. You'd be looking at something offered by Fuel injector clinic, Fuel injector connection or Deatchwerks. They all offer those size injectors with the proper data for tuning.

    If you just need something to get you buy for a while look into some factory 8.1 injectors that are 31lb/hr or find some stock flex fuel injectors from the same era. Those are 33lb/hr and come on trucks/suv's from 2002/2003 to 2007. Those can just just copy/paste the injector information from another factory tune. Either injector will support a cammed 6.0.


    2 bar and 3 bar kinda mean what they say. A 2 bar MAP will run out at 14-15psi and the 3 bar above 28-29psi. You could run either sensor as it doesn't really matter. The data is the only thing that matter, it needs to be correct for whichever sensor you bought.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

    If you don't post your tune and logs when you have questions you aren't helping yourself.

  6. #6
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    Going to get what injectors I will need in the end and looks like the 2 bar will be what I will go with.On with more research.

  7. #7
    Senior Tuner cobaltssoverbooster's Avatar
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    Quote Originally Posted by 89 Caprice 6.0L View Post
    It was set at 550rpm stock and I bumped it up to 630rpm,it seems odd that it only happen in reverse,will bump it up some more.
    I know my stock injectors are running almost at the limit now,looking for recomenditations on replacement ones.
    New parts going in now
    BTR Stage 2 Turbo, Duration 226/231, Lift .605/.598
    Summit Racing? Pro LS Upgraded Rocker Arms SUM-141556
    Summit Racing? LS Lifter and Guide Kits SUM-HTLSKIT
    Next purchase will be a 3800 stall converter.
    Then will come the turbo.Planning on about 10lb of boost.
    Would flex fuel injectors be enough to feed it? or need bigger?
    What MAP will I need? What are the limits on 2bar and 3bar
    I have bookmarked and been reading everything on how to tune with a cam.
    my drag motor has similar valvetrain components and a 4500 stall yank converter for a powerglide conversion. i like it a lot.
    im running ID1000's and in n/a trim the are floating around 30% duty cycle with 43.5 psi at regulator. they should handle 950hp no problem since i have headroom in the rail pressure if i need it.

    as 5F stated: if you dont plan to go higher than 10-12 psi then you can run a 2 bar sensor. the 3 bar is more common and allows for room to grow if desired.
    according to DW, 600 crank hp requires a 60 lbhr injector. if you plan on going higher boost later just grab some 750cc or 850cc injectors. (these are also E85 flow ratings so if you run pump gas then it will just give you more flow headroom to make the same power since e85 requires roughly 30% more fuel flow than pump gas to maintain lambda ratio)
    dont forget to upgrade your fuel pump to a high flow rate pump.
    Last edited by cobaltssoverbooster; 08-14-2019 at 08:46 PM.
    2000 Ford Mustang - Top Sportsman

  8. #8
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    Thank You for the reply's and recommendations,will do some more fact finding and when "money bags",my son, gets the funds together,the fun begins.

  9. #9
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    I was actually looking for comments on the tune. Do I have all the settings correct for drag racing.Do I have the knock sensors desensitized correct.I think all the torque management settings are off.Are the trans settings correct. Just wanted to check on how I am doing.