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Thread: 1972 Elcamino 1993 Camaro Z28 LT1 T56 6 speed

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    1972 Elcamino 1993 Camaro Z28 LT1 T56 6 speed

    Hello to all. been lurking here and there gathering info for my camino. I am on a couple other forums and have been gathering there as well. I have just started tinkering with my ride and have to say this site and the others have been a lot of help. I know the LT1 is kind of outdated but the cool thing is a lot of the tools and tricks have been tried and proofed so it helps a lot. I am not new to wrenching have done it all my life as a hobby. But this is my first injected ride.
    So for a little history: 1972 Elcamino 1993 Camaro Z28 LT1 T56 6 speed. I have gone through the tranny and upgraded to a viper mainshaft brass keys and shifter fork buttons. That spins a gm 12 bolt with disc brake conversion 4.11 gears and a Eaton locker no hop bars and adjustable upper control arms. The computer has been changed out for a 95 ECM. It is easier to get a replacement (at the time I was having trouble there were none to be found in the US) spent 2 years looking and finally on advice from Zac at Speed Scene Wiring we changed. Along with a more readily available supply I also got the benefit of sequential fire injection. I also just recently converted to a Bailey engineering LTCC conversion. Firing NGK TR55's gapped at .060. It's running a BBK 58mm throttle body, K&N Cold air kit picking up on the left front fender. Racetronix in tank fuel pump and dedicated power supply harness. Headman Elite mid length headers with 3 inch collectors dumping into 3 inch 2 chamber Flowmaster Delta force silencers and then 3 inch all the way over the axle to the bumpers all mandrel bent. I have a 2.5 inch crossover to help with the sound a little.
    So I have been slowly getting things sorted and have found some things out as well. I am have been datalogging and have noticed that I am predominately at 108 on the blm readings. After looking here at some threads i found that i may need to scale back my injector values. I am running 45psi at idle and 44 at 2k unloaded of course just setting in the drive. cracking the throttle jumps it to 50psi. So i am figuring that is why I am stuck in the 108's. Also my log graph looks like a seismic even for a 7.9 earthquake. Not sure if it's my logging or if my system is that wacked. Truck runs great be it a little fat but not smoking just smells that way.
    If anyone has a log of a good run with Tunerpro V5 I would like to get a look at it to see if I am seeing it right
    Last edited by beestoys; 01-28-2014 at 09:56 PM.

  2. #2
    Fuel Injected! steveo's Avatar
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    so just to be clear, you are running 1993 stock injectors with a 1994-1995 harness and ecm?

    this is important; as the stock '93 injectors are 22lb, but the '95 pcm is set up for 24lb injectors by default. add some extra fuel pressure and you're going to be way out to lunch.

    but it should be running lean, not rich!

    the stock injector constant assumes 43.5lbs tops, you're hitting 50lbs. this is max, without any vacuum to the regulator.

    so you adjust for fuel pressure using sqrt(actualpressure/ratedpressure)*injectorsize. that gives you sqrt(50/43.5)*24=25.73

    what is your injector constant right now anyway?

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    Steveo
    The harness is a custom build by Zac, it incorporates a 95 ECM running the 93 hardware. I have the EGR blocked and no air pump it has the AC circuit still in there but it's not used right now. Also I have no charcoal canister or any emissions equipment for that matter. It is running the knock sensor in the stock location.

    I'll have to check to see what the constant is. I did download the tune that Zac put in for me so I'll see where he has it set. I am new to this so I'll see if i can find it. (man there's a lot of info in the tables and scalars) lol.

    Yes and that 43.5 max is actually what I am running at under normal cruise (actually 44 no load in driveway). So I am figuring that is why the ECM is trying to pull it back all the time. On a side bar changed out the plugs pulled out E3's and they were all dark brown so that confirmed my believing it running rich. I also noted that the pressure gage is not holding line pressure after the pump cycles. I ended replacing the stock pump for this issue as well as a flat spot. So I am thinking i have either popped another check valve or I have a bad injector. We are going to scope it this weekend and see if any of them are leaking. I will also to an infrared check on the primaries to verify all appears to be balanced. I checked it when we first lit off the new ignition system and they were good but I'll double check them.

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    Steveo
    Looks like it's set at 24.912 so with that I am thinking Zac made a correction for the bigger injectors. I'll get some hard numbers and run them through that formula. This is why I wanted to go down this road. Giving someone a generic idea is good but I have found real world is never generic.
    On the lean note if I have more pressure than factory shouldn't it be running fat hence my BLM's being at 108 which would tell me the system see's that and is trying to pull fuel out?
    Last edited by beestoys; 01-29-2014 at 08:22 AM.

  5. #5
    Fuel Injected! steveo's Avatar
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    no thats the thing, your injectors are smaller if they're from a 93. i actually screwed my math up above, i did it for 24lb injectors. yours are 22lbs. your injector constant should be closer to 23.58

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    Ok I see so calculate at 22 I'll run the numbers with that then and see what happens. This thing is violent now I can imagine what it's going too be when it's leaned out some and running stronger.

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    EFI GearHead ! EagleMark's Avatar
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    The 24.912 is a stock setting for some... Calculating injector flow and setting Injector Off set voltage in calibration is always a better first step in tuning, before tuning! Getting it right should get the BLMs closer but tuning is still in order.

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

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    Quote Originally Posted by EagleMark View Post
    The 24.912 is a stock setting for some... Calculating injector flow and setting Injector Off set voltage in calibration is always a better first step in tuning, before tuning! Getting it right should get the BLMs closer but tuning is still in order.
    Mark would injector offset voltage be the value Steveo had me calculate or is there another number I need to check as well. Did a log on the run into work but messed up my Tunerpro settings and I can't remember my setups as I am just now using this thing LOL. It does seem to be running better though so thinking I am making headway. I'll get my system back up and take a look at the run in today.
    Thanks for all of your help
    Brian

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    Quote Originally Posted by EagleMark View Post
    The 24.912 is a stock setting for some... Calculating injector flow and setting Injector Off set voltage in calibration is always a better first step in tuning, before tuning! Getting it right should get the BLMs closer but tuning is still in order.
    Well asjusting the flow rate did help I was able to get a look at my run on the dash and it is staying up around 128 more. I am going to have to do a major adjust in the idle area. open loop cold it's at 128 and the 02 sensors look like they are staying up around .9 or a little higher. IAC is hovering around 40 or so till it comes off open loop. Then you can hear and see it crash to 108 although with the new injector rate it isn't as pronounced in the engine tone. It actually stays up for a longer time now before it goes south. So I'll scope the injectors this weekend and see if any are leaking. The next order of buiseness will be to get the zietronix wideband in the cross pipe and tie it into Tunerpro for the AFR so that I can log it along with the other values.
    I have a second question.
    When I look at my runs in the 3D graph they don't look anything near smooth. It looks like the Ande's mountains, I am I missing something when I plot. I am going to go through the Tunerpro sticky section here and educate myself some more but was just looking for a quick confirmation for the steps to plot.
    Again thanks a bunch for your inputs and help
    Brian

  10. #10
    EFI GearHead ! EagleMark's Avatar
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    Quote Originally Posted by beestoys View Post
    Mark would injector offset voltage be the value Steveo had me calculate or is there another number I need to check as well.
    Brian
    It's another Parameter. You'd have to open the LT1 from 93 $DA3 and get the Offsets and place them in your $EE bin.

    Quote Originally Posted by beestoys View Post
    Well asjusting the flow rate did help I was able to get a look at my run on the dash and it is staying up around 128 more. I am going to have to do a major adjust in the idle area. open loop cold it's at 128 and the 02 sensors look like they are staying up around .9 or a little higher.
    Brian
    It will read 128 in OL, then when closed Loop is when you get feedback for BLM adjustments.

    Everything from CAI, higher fuel pressure, cam etc... will play a role in what the numbers are. Always start your log when warmed up and driven. Gives less false data to remove when using the BLM numbers to adjust from. Also having EGR, DFCO and PE off helps get more solid BLM numbers to adjust with.

    Could be why your seeing such big differences?

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

  11. #11
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    Quote Originally Posted by EagleMark View Post
    It's another Parameter. You'd have to open the LT1 from 93 $DA3 and get the Offsets and place them in your $EE bin.

    It will read 128 in OL, then when closed Loop is when you get feedback for BLM adjustments.

    Everything from CAI, higher fuel pressure, cam etc... will play a role in what the numbers are. Always start your log when warmed up and driven. Gives less false data to remove when using the BLM numbers to adjust from. Also having EGR, DFCO and PE off helps get more solid BLM numbers to adjust with.

    Could be why your seeing such big differences?
    Thanks
    I should be able to just download a 93 bin and get the numbers right? and then transpose them.

    Can you just turn those parameters off with Tunerpro or do you have to set values to cause it not to activate?

    EGR shouldn't be a problem as it's all disconnected anyway. I'll try and do a log run after setting it up like you mention and see what happens.

    We are going to scope the injectors this weekend to see if they are leaking and the reason my rail pressure drops after the pump cycles. I'ts a new pump so I don't think the check valve has gone already but we'll see.
    But if it is an injector what would be the benefit of changing all of them to a 95 version. (Besides the obvious not having to change all this in the ECM to 93 injector specs)
    Thanks again.
    Last edited by beestoys; 01-30-2014 at 04:03 PM.

  12. #12
    EFI GearHead ! EagleMark's Avatar
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    Not sure on injector change? steveo is way better in LT1 then me so we'll see what he says. If you get or have a set of used injectors always have them serviced before the install. If there's no shop near you look up Mr Injector.

    EGR needs to be turned off/disabled in bin as well as removed or it may think it's still working and change fueling and spark.

    You can open two instances of TunerPRo when you need parameter values from one mask ID to another. Open TP, load XDF and bin, then Tools, Custom Tools and New Instance of TP. Then you have 2 screens to copy and paste from.

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

  13. #13
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    Agreed on the service of them.
    I'll do some digging and see what I can find on the EGR and see where it's set. I am thinking I saw it in the scalar section and it had settings in there. So I am thinking it's still active. Is there a section in Tunerpro where you can go an see if some of this stuff is on or off.
    I'll try the dual look and see what I can find.
    Sorry for all the questions been a gear head all my life but I have just recently got into the electronic side of it this deep anyway LOL.
    And thanks again for all the help.

  14. #14
    EFI GearHead ! EagleMark's Avatar
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    While data logging you can see EGR duty cycle.

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

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    I'll check it tomorrow then with scan9495 and see what its doing.
    Thanks

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