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O2 Sensor on Holley 2d system

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  • O2 Sensor on Holley 2d system

    This is a great informative form- I like it...

    I have been running a holley 2d injection system on a 73 scout with a fresh 345. I only get about 8 miles to the gallon, where I used to 14. They changed the fuel up here to 10% ethenol and was wondering if this would cause that much change.

    Next the question- I have installed a holley closed loop system on the truck and need to now if the light should say green al the time or move between the lean and rich. I am trying to re-tune the system to higher altidue. I came from OK and know live in Denver. I think I should get better mileage. The truck does run great but dang.....

    The truck has 33x12.50*15 amd 4.10 gears.

    Brian
    Brian Tucker
    Bennett, CO

  • #2
    If the holley closed loop is set up like the GM system than it should roll from rich to lean at a steady rate. it is designed to keep the CAT operating efficiently by varying the AFR.
    You need to check the book that came with it and see if it is normal. my GM system goes from .04 volts to about .78 volts if memory serves me.
    All the holley systems I have seen seem to be a rich. but none have the O2 sensor for closed loop, they are the older analog system without the closed loop option.

    HTH
    Bill USN-1

    COMMITED TO TEACHING PEOPLE THE "PROPER" WAY TO EFI
    HAMILTON FUEL INJECTION
    May be the answer to all your fuel injection needs!
    Learn to do it right.

    Comment


    • #3
      Brian,
      Bill is correct, the closed loop voltage range on my Holley 4Di is suppose to range from .05v - .8v, although in a note in the testing section mentions the 4D range of 0v - 1.0v. The Closed Loop mode only makes small changes, so you have to have it tuned pretty close before the Closed Loop can optimize the mixture. Monitoring operation with my lap top, my 4Di oxygen sensor voltage jumps around constantly, a very neurotic element.
      Mickey

      Comment


      • #4
        The 2D projection is very simple design. I think the 2D is more of a special Carb than FI, due to the low number of sensor it uses.

        I have read through the holley installation guide several time and wonder of the last few years I have been running fuel injection if it is tuned correctly. The system doesn’t use a laptop, there for the ear and a vac gauge was used to tune the truck.

        What methods have you guys used to properly tune the old analog systems? I do have the closed loop system and monitor. Which could be hooked up to read the O2 meter without going through the CPU.

        I am attempting to learn complexities of FI and possible find a better system for my daily driver. I believe a Scout can be made to get 18 miles to the gallon with a properly configured system including FI, Ignition and Gearing.

        Brian
        Brian Tucker
        Bennett, CO

        Comment


        • #5
          Given your options I would disable the closed loop and tune the motor in open loop with a vacuum gauge, tach and the air fuel meter. Then when you are optimized you can hook the closed loop back up to adjust for weather and altitude.
          Bill USN-1

          COMMITED TO TEACHING PEOPLE THE "PROPER" WAY TO EFI
          HAMILTON FUEL INJECTION
          May be the answer to all your fuel injection needs!
          Learn to do it right.

          Comment


          • #6
            Then--- lets look at the complexity of properly tuning the engine. How do you know when the engine is properly tuned?

            What is the correct fuel pressure? TPS setting? Distributor Advance will that play a role? What is a good Vac reading?

            I am not trying to be difficult.

            Where would you start? The engine (345) has only 40,000 miles since new motor. I have a Jacobs Mileage Master, Pertronix Ignitor, and Plugs gapped at .050. The truck runs good, but once again, I believe a scout should get over or at 15 mph on the highway. Is 600 CFM enough fuel for the Motor...?


            I live at 5480 ft and drive into Denver every day which is 5280 ft (mile High City). I think I have the trucked advanced at 20 degrees. No Ping.... I am thinking of changing to HEI. The fuel injection fuel pressure runs at 11 psi. The truck runs a little lean at idle, but richens up when I drive down the road. I drive about 55 to 65 mph. I find that I have never been able to get the fuel map right on this unit. I think I should be able to tune the fuel injection to run at in green on the holley lean/rich indicator. I also believe the unit should be able to maintain this when driving at a constant speed instead of jumping from lean to rich all the time.

            I am looking for advice on way to understand and correctly id problem with the holley system. If I can make this system work then I will continue to use it. However, I am looking at a daily driver that I would like to get extremely good mileage on a consistent basis. I may change to a better FI system bur for know I want to master what I have. What other options are there for complete FI controlled, vac advance, ECT. Basically turn the key and drive from sea level to 14,000 without changing anything. If we build, it will come.
            Brian Tucker
            Bennett, CO

            Comment


            • #7
              To answer one question I found this on the IHC Digest today from Darrel.
              "> On your 345, I believe it has been decided that 4200 is max, my service
              > manuals and specs tell me it is 100 RPMs less than the 304 so the 345 is
              > 3800, so say you went with 4200 RPMs ... 345 x 4200 = 1449000 / 3456 =
              > 419.27083. A 419 cfm carb would be ideal, but not likely to be found, so a
              > 500 cfm will be your only choice. "

              They were talking about carbs but your 600 cfm is plenty.
              What Holley has 600 CFM?
              I thought the two barrel was 670?

              As far as elevation goes woudn't that be compensted for by an O2 sensor?
              [CENTER]1994 Buick RoadMaSSter Estate Wagon LT1/4L60E. White and Woodgrain Sleeper...PCM 16188051 With SS/V4P/Custom Tune! WOT 12.9 AFR!

              1990 Chevy Suburban Silverado 5.7L 2wd ECM 1227747 HiWay Lean Cruise 18.5 MPG and 12.5 to 1 AFR at WOT!

              1972 IH 1210 Isky Cammed Balenced 345 4 speed PCM 16197427 Project!

              [SIZE=3][B][URL="http://www.gearhead-efi.com/"]GearHead-EFI.com[/URL] EFI Conversions and Chip Tuners![/B][/SIZE]
              [B]May be all you need to know about EFI![/B]

              and I still help local JustIH members (for fun) free! :cool: [/CENTER]

              Comment


              • #8
                http://www.nastyz28.com/perftune.html#supertune

                start with this site for some basics.
                Bill USN-1

                COMMITED TO TEACHING PEOPLE THE "PROPER" WAY TO EFI
                HAMILTON FUEL INJECTION
                May be the answer to all your fuel injection needs!
                Learn to do it right.

                Comment

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