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Thread: 16196395 and High Impedance Injectors

  1. #1
    Fuel Injected! corvairnut's Avatar
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    16196395 and High Impedance Injectors

    Latest thing Im doing is getting away from 2 wet TBI and to a single dry TBI with Injectors at the base where the carbs used to be. Got everything fab'ed up and didnt even have a fuel leak, but it wont run.... and appears to be a fuel problem. It will run it by spraying fuel into the throttle body, but stops after I quit "being the injector"

    Im using a 16196395 ECM and high impedance injectors (Ford 27 lbs x 2). Have taken the injector out to observe the injector and it has a weird spay rythym, but spraying. I thought I read somewhere, I think on the forum where the 16196395 can handle up to 4 injectors without modification. Bill at binder posted about putting a wire on a resistor to use many injectors, but dont know if this is the same thing.

    Now my Question: Can I run high-Z injectors (Ford EV6) on a low-z (16196395) ECM?

    Ohms of the injectors I was testing:
    GM TBI - 1.8 ohms (Low-Z) - FACTORY
    Ford EV1 Injector - 2.8 ohms (Low-Z)
    Ford EV6 Injector - 12.0 ohms (High-Z) (the one I was testing)
    Last edited by corvairnut; 03-04-2013 at 03:00 AM.
    Ted Brown
    Anderson, SC
    68 Corvair EFI
    61 Corvair Loadside Pickup (Future EFI)

  2. #2
    Fuel Injected! corvairnut's Avatar
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    I think I have the answer. Bill from BinderPlanet has a writeup on how to splice two resistors to make the 16196395 and its cousins for multiport injectors. I asked for clarification and said doing this mod would make the ECM a high-z controllable ECM.

    http://www.binderplanet.com/forums/s...d.php?t=101802

    I will give it a try tomorrow and report back.
    Ted Brown
    Anderson, SC
    68 Corvair EFI
    61 Corvair Loadside Pickup (Future EFI)

  3. #3
    RIP EagleMark's Avatar
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    All that was developed long ago on Thirdgen.org. We have all the writups guys have done on other sites and info on the MPFI conversion here:
    http://www.gearhead-efi.com/Fuel-Inj...Information-OD

    What Bill is telling you is WRONG!!! There is no need to jump resistors unless you have 8 saturated injectors.

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
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  4. #4
    Fuel Injected! corvairnut's Avatar
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    Well... you may be right. The injector done the same thing with the jumpers on and off... which is not enough fuel per pulse (45 lbs of line pressure). I'm driving 2 EV6 (high-z) injectors (#30 lbs) instead of 2 TBI injectors (#27 lbs) with the about the same FPH rate and not doing a MPFI conversion. Common throttle body with tubing to each intake (Corvair). Injector is at base of tube at the entrance of the intake log on each side. I thought this would be simple as all I'm changing is the location of the injector. I have ordered low-z injectors to see if that makes a difference as the TBI injector puts out a lof of fuel and currenty the high-z injectors are not.
    Since Bill is Wrong... your saying the 16196395 style ECM will fire the high-z injector normally?
    Ted Brown
    Anderson, SC
    68 Corvair EFI
    61 Corvair Loadside Pickup (Future EFI)

  5. #5
    RIP EagleMark's Avatar
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    Since your not in MPFI I'm not sure what the injectors would do? Did you install the Injector Offset vs Batterey Voltage? Injector Flow Rate?

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
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  6. #6
    Fuel Injected! corvairnut's Avatar
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    Removed the jumper on the resistor as it DIDNT make any difference. Offset vs battery voltage was already set in my bin. The flow rate was right for TBI, but changes when you go to CPI mode and done that on the fly back and forth.

    Solution: Went back to a low impedance injectors and started right up using my exisiting bin with only 1 mod. It seems to run much better and easier at idle in CPI mode. You have to reset the lbs per hours when changed from TBI mode. Starting getting dark and I have this engine sitting on the movers cart...so its back into the shop and awaiting some new Low-z injectors that are the right size.
    Ted Brown
    Anderson, SC
    68 Corvair EFI
    61 Corvair Loadside Pickup (Future EFI)

  7. #7
    Electronic Ignition!
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    Old thread but i have thought about doing the same mod. Im thinking that the fuel pressure reg would have to be vacuum referenced when putting the injectors below the throttle body or major fuel flooding would occur at idle

  8. #8
    Fuel Injected!
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    Two things the low-z hi-z issue is mute on the 1995 and earlier GM ECMs the injector circuit is a MosFet to ground the low Z injector draws a lot more current than the high-z so using a Hi-Z on a low z driver is electrically ok.
    But the other issue that he was not clear on is that the high-z injectors are usually used in MPFI systems and only fire 1/6 1/8 of the RPM on the GM TBI elms the fastest I have been able to trigger the pulses is about 8000 rpm before the Mosfet slew is as long as the injector pulse.
    I use ford Econoboost injectors on my LT-1 with stellar results I think he may have had wiring issues.

    As far as below or above throttle body on the old TBI injectors the pintels had a tendency to close slower under vacuum.
    The bosch style injectors operate well under vacuum or boost enabling port fuel injection.
    The fuel pressure regulator on a TBI unit is atmospheric referenced if you use boost you have to add a manifold referenced regulator.
    If you have no boost you can use the stock fuel feed line for secondary injection fuel the pressure will be fine.
    On turbo hat TBI units all you need to do is put the sealed cover on the regulator spring and run the hose to a fitting at manifold pressure.
    JBweld works to sculpt the plate around the wires and the little space by the fuel lines.
    The boost fuel is provided under the throttle plate with old fashioned L98 TPI injectors stuck into the TBI spacer.
    Avatar is my motor 800 RPM 184ft Lbs Torque 18 inches x 18 inches x 9 inches thick external combustion engine.

    98 WS-6 full tube chassis rally car Aluminum Block LS2 (soon to be LSX 376)(in Storage)
    95 Suburban 6 inch drop, Pioneer DVD in Dash 5.7 TBI, 220cc 2.02x1.60 64cc heads, Stainless longtube headers 2.5 crossover 3 inch exhaust, LT-4 roller cam.
    2002 Seville STS

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