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New EFI Option - Looks Like 3 Good Players Now

Discussion in 'Early CJ5 and CJ6 Tech' started by Warloch, Nov 8, 2017.

  1. Mar 19, 2020
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor 2021 Sponsor 2020 Sponsor

    Medford Mass USA
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    This is an interesting complaint. An electronic system does not need to do work lifting fuel or moving diaphragms with the vacuum, like your carburetor or vacuum advance does. If your conversion were all-electronic, detection of the vacuum would be all that matters. The Rochester throttle bodies have only 2 venturis for this reason. No need for progressive opening - they simply make them bigger as needed.
     
  2. Mar 19, 2020
    Fireball

    Fireball Well-Known Member 2022 Sponsor 2021 Sponsor 2020 Sponsor

    Pullman, WA
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    It's not really a mixture problem, it's just that a small movement in throttle position make a BIG change in how much air is getting into the engine and hence how much power you're making. It's hard to be smooth. My Mustang with a 90mm throttle body is pretty touchy.

    You wouldn't necessarily need progressive secondaries. Progressive linkage between the throttle pedal and throttle plate would also work.
     
  3. Mar 19, 2020
    BadGoat

    BadGoat How High Can You Climb?

    Northern Virginia
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    I have this issue on the one on my F100. I have a 64 F100 with a 351C running the Holley Sniper. It's very touchy coming off idle. Holley offers two solutions. 1 is a progressive throttle control as part of the software. It seems to cause some other driveablity issues when used. 2. They offer an extension to the throttle lever on the Sniper unit that seems to be a better fix. I don't currently have access to the truck, but will be trying this fix this summer or fall.

    Mike
     
  4. Mar 19, 2020
    Ns0mniac

    Ns0mniac Member

    San Clemente, CA
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    Aug 7, 2019
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    I have the same problem with my sniper equipped 350, it's been mostly remedied by the longer lever but I'll be installing an EFI Systems Pro linkage kit later that adds progressive linkage. You need to flash the computer to install it, also stops you from being able to run a vacuum advance distributor because Holley ran the vacuum off the secondaries. Between that and the better pedal assembly I hope to have a driving experience with fewer unintentional burnouts :whistle:
     
  5. Mar 20, 2020
    gibson-d@sbcglobal.net

    gibson-d@sbcglobal.net Member

    Houston, TX
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    I have a Howell kit for my '84 CJ7 with an adaptor for the factory Carter 2bbl. Maybe this adaptor could be made to fit a 2G manifold. Just my $ .02.
     
  6. Mar 30, 2020
    jwinsley

    jwinsley Windblown

    Kauai
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    May 4, 2011
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    Well, the Holley 2300 TBI is in. Fired right up. Idles good. I have to tidy up wires and fuel lines before I can take it for a spin. The Holley is a bit shorter than the Rochester, the Holley is 4" tall but I gained a inch with the 2 to 4 barrel adapter so it ended up about the same height as the 2G. Easy hookup, the tach wire out of the HEI runs into the Sniper Harnes and then the Sniper has a wire that comes out and goes to the tach, 12V positive and negative off the battery, switched ignition positive, new fuel line and new fuel return, O2 Sensor and temperature sensor. Nothing particularly hard. I hope to have it driving tomorrow.
     

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  7. Apr 3, 2020
    jwinsley

    jwinsley Windblown

    Kauai
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    Well, I have driven the jeep back and forth down the local road. It runs good but the little display panel the sniper comes with, the RPM jumps all over the place. At idle it bounces between 580 an 950 constantly. The tachometer sits steady but at about 400 rpm. I have started talking to tech support but also stuck an oscilloscipe on the HEI tach output. Images attached. I see a different spacing every 2 pulses. The vertical lines are at 25msec increments. Can someone check my math? If I see a pulse every 25 msec and they are offset in groups of 2 I would think that means the tach signal pulses every firing, not once per revolution. That means after 125 msec (or .125 seconds) I fire the same cylinder again. So the motor makes 2 revs every .125 seconds or 16 revs every 1 second or 960 rpm, which seems a little high but this is a course reading of the scale.
     

    Attached Files:

  8. Apr 4, 2020
    Fireball

    Fireball Well-Known Member 2022 Sponsor 2021 Sponsor 2020 Sponsor

    Pullman, WA
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    I'm seeing 7x 0.025s intervals before the same cylinder fires again. That's more like 685rpm.
     
  9. Apr 4, 2020
    wasillashack

    wasillashack Member

    Wasilla, Alaska
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    I have a question(s) for those of you who are more familiar with the electronics aspects of the odd fire EFI. I have a NIB MSD 6 Part Number 6246. This unit was engineered especially for odd fire V6's according to MSD. Anyone have any experience with this unit? I was wondering if it will supply the correct tach signal to run an EFI such as a GM based unit. If the tach signal is "averaged" to send a signal to make the tach work, would this in turn be correct signal to make the TBI ECM function properly?
     
    Last edited: Apr 4, 2020
  10. Apr 4, 2020
    zinertia2

    zinertia2 "and which part are you keeping?" 2022 Sponsor 2021 Sponsor 2020 Sponsor

    Greencastle , IN
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    Is there an issue with the way the engine runs? Is it only the Controller that is an issue?
    Dennis
     
  11. Apr 7, 2020
    jwinsley

    jwinsley Windblown

    Kauai
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    No, the engine is running better than with the carb, starts faster. In addition to the uneven pulse from the HEI tach on the oscilloscope I downloaded a data log file off the sniper. Its shows a sawtooth RPM pattern thats reflects what the RPM readout displays. I have been going through the Sniper laptop programming software (not the little 3" display). That software has the option to add a magnetic RPM input. The manual says "Magnetic – Use if you are connecting to a magnetic pickup. Does not matter whether ECU is controlling timing or not.". That seems to imply I can bolt on a magnetic pickup and ignore the HEI tach input and avoid the problem. I am trying to get some additional infor out of Holley since the manual doesnt have any other infor. Holley does have a $393 dollar universal crank trigger kit but I dont think I need that level of accuracy. Not trying to control time. Just get RPM.

    I do need to adjust my throttle pedal ratio to make the response less touchy, but thats relatively easy, thats mechanical.
     

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  12. Apr 7, 2020
    Warloch

    Warloch Did you say Flattie??? Staff Member

    Falcon, CO
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    If it's running good I'm wondering why your concerned about the pulses your seeing? Holley has always stated they don't support an Odd Fire engine. You can tap the HEI tach signal and run a tach of your own if you wanted to. If its a self tuning - closed loop setup, it should tune it self and just work based on the target O2 reading at any given set of inputs... no reason to 'even out' the pulses if its working.
     
  13. Apr 7, 2020
    Warloch

    Warloch Did you say Flattie??? Staff Member

    Falcon, CO
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    I tried to get one of those when they were just going off production from MSD - never did and ended up keeping the HEI once it was found to work fine. At the time, I was looking at the Megasquirt setups.
     
  14. Apr 10, 2020
    jwinsley

    jwinsley Windblown

    Kauai
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    I thought about just leaving it running the way it is but I think I will lose out on some of the ability and performance of the FI if I do. As I read the programming software manual its looking at manifold air pressure and RPM to adjust fuel (on dataview.jpg, the lower red line (almost on the zero axis) is the fuel flow constantly varying (the injector pulse width is the the green line above the lower red on dataview.jpg)). As the RPM goes up the RPM error increases also.

    It also seems like that constant cycling will also start to wear on the injector. I also lose out on some of the cold start idle control benefits. Apparently you can also adjust how quickly the engine drops back to idle, not sure if I would ever need that.

    I have a crank sensor on order and that signal can feed straight into the Sniper.
     
  15. Apr 10, 2020
    wasillashack

    wasillashack Member

    Wasilla, Alaska
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    Warloch, I have been told that MSD will "reprogram" an MSD unit to make it compatible with a Dauntless. This is not an advertised service. IT has been awhile since I talked to them about it, so it may no longer available. I have talked to you regarding TBI on a Dauntless quite awhile ago. I started off thinking MS, but the learning curve seemed to be pretty steep for me. Technology and I don't play well together. Plus I had planned on using this on a DD and had concerns about parts availability and costs. The MSD 6246 I have can be used in conjunction with an HEI using MSD wiring harnesses, at least the literature that came with my unit says it can be.
     
  16. Apr 11, 2020
    Jrobz23

    Jrobz23 Member

    Northern, WI
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    If you use a normal uniform V6 crank trigger and setup the Sniper for a ‘points’ dist, I’m failing to see how this wouldn’t work.

    Let the HEI handle spark and don’t integrate the two.
     
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  17. May 30, 2020
    Hônes

    Hônes New Member

    Colorado Springs CO
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    (I know this discussion was from last month) I had to have the trigger wheel on my GM TBI conversion. The ECM was reading the odd-fire’s closely-spaced cylinder firing as high rpm followed by the next wider gap as low rpm and couldn’t get the continuous running that you’re experiencing. The FI was trying to match the assumed rpm changes it interpreted as high-low-high-low and it couldnt keep up. Thus enter the crankshaft magnetic trigger wheel connected to the ECM and custom fuel mapping on a prom chip from Howell. Mine would run for a few seconds at best without them. The ECM was off a ‘92 305 Camaro and just needed an even fire signal. It didn’t care necessarily that the engine under it was a V6.
     
    Last edited: May 30, 2020
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  18. May 31, 2020
    Mjragan

    Mjragan Member

    socal-Simi Valley
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    I have been running the GM TBI on my odd fire for about ten years now and am very happy with it. The GM TBI system fires the injectors each time the ignition fires, in the stock setup the ECM receives an rpm reference signal from the ignition module located in the distributor. The reference signal is a 5 volt square wave input to the ECM, so every time the ignition fires a cylinder the ECM receives a single 5v pulse and then the ECM fires the injectors. For fuel control the ECM doesn't know or care if it is getting an even or odd firing signal. You can use the tach signal from an HEI or negative post on the coil on a points system as a trigger, both these signals are on the primary side of the ignition circuit so the voltage is to high and dirty for an input to the ECM so it needs to be filtered and converted. Tach filters and signal converters are cheap about 40$ and will provide the ECM with the signal it needs. I think the tach output on the MSD box is 12v but I'm not sure, as long as the signal reflects the odd firing pattern you should be able to use a signal converter to drop the MSD output to the 5v signal for the GM ECM. Below are some scope captures the top capture show the relationship between the ignition reference signal, secondary ignition (cylinder firing) and the injector firing on a 1995 Chevy PU 5.7L. The second capture is from a 225 odd fire and shows the uneven odd fire pattern.
    Hope this helps Mike
    IGN. REF1.jpg IGN.1.jpg
     
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  19. May 31, 2020
    Mjragan

    Mjragan Member

    socal-Simi Valley
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    Not to ramble on but here I go. Is there a down side to triggering the TB EFI off the ignition on an odd fire engine? I'II try to explain but before I do I've been triggering the EFI on my odd fire off the tach pickup on an HEI for almost ten years and it runs great and has never giving me any problems. With that said I'm going the throw something out their, on an even firing engine the intake valves on all the cylinders are opening at equal degrees through the 360 degrees of the crankshafts rotation. The intake valves are opening just before top dead center (TDC) at the end of the exhaust stroke, on an even firing engine (with an even number of cylinders) there are always two cylinders at TDC at the same time (companion cylinders) one is at the end of the compression stroke and the other at the end of the exhaust stroke, the ignition is going to fire the cylinder at the end of the compression stroke and the intake valve is going to open on the companion cylinder, as both pistions move down the cylinders one on it's power stroke the other on it's intake stroke. So buy firing the injectors in sync with the ignition on an even fire engine there is always a cylinder on the intake stroke when the injector fires, makes sense but that is not the case with the odd fire because not all the cylinders share equal degrees of TDC through out the 360 degrees of crankshaft rotation. In the captures above the 5.7L is firing every 90 degrees (evenly) compared to the odd fire 90-150-90 ect. I'm probably overthinking things but maybe some day when I get some spare time I'II change the way I trigger my EFI.
    Rambling over stay safe.
     
  20. Jun 1, 2020
    BadGoat

    BadGoat How High Can You Climb?

    Northern Virginia
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    Hypothetically, having the injectors fire in time with the valve openings should be more efficient. Letting the injectors fire at a regular interval, with irregular valve openings could cause some of the fuel to come out of suspension for the brief period it sits in the plenum waiting for the valve to open. How much this would affect the motor is really hard to say.

    Mike
     
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