Can't Get Over 1800 RPM

Discussion in 'General IH Tech' started by kylescars, May 15, 2019.


  1. kylescars

    kylescars Farmall Cub

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    I'm having a weird issue with my Scout II and I hope there's something I'm missing. I cannot seem to get it over 1800 RPM while in Drive. Throw it in neutral, revs right up to over 4k. But in drive I can mash the pedal to the floor and only get about 1800. It also seems like there is very little usable throttle.

    I think it's safe to say the throttle cable is good, I can use the pedal to hit high RPMs in neutral. So where do I go next? Fuel delivery settings? Kickdown? Trans? Is this a silly question and I've missed something very obvious?

    1976 Scout II
    FiTech 2 Barrel w/ Fuel Command Center
    DUI Distributor
     
  2. Packerrailway

    Packerrailway High Wheeler

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    I'll only ask what I was told in driver's ed 40 plus years ago. IS YOUR PARKING BREAK ON? That is the simplest explanation.
     
  3. kylescars

    kylescars Farmall Cub

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    Lol nope! I wish it were that simple!
     
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  4. Dana Strong

    Dana Strong Dreams of Cub Cadets

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    Does that transmission allow you to manually downshift into first or second gear while driving?If so, try that and report back.
    Sounds to me, assuming everything (timing, spark, fuel pump delivery) else is correct, that the high speed circuit or power valve enrichment isn't operating correctly. I once had a similar situation in my '61 model 80 where I suddenly had no power, although the engine idled fine. I removed the fuel bowl and found a piece of wheat straw sticking out of the main metering jet. May have been floating inside for months, but chose then to find and partially clog the hole.
    What carburetor (List number) do you have?
     
  5. kylescars

    kylescars Farmall Cub

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    I'm able to knock it down into second gear (though it doesn't seem to let me push it all the way down to first gear) and the same symptoms occur. No carb on this one, I'm running a FiTech 2 Barrel fuel injection setup. It's about a month old so I wouldn't expect it to be gunked up. Engine idles great, runs around the neighborhood great, just doesn't seem to want to hit higher RPMs while in Drive (or under load I should say).
     
  6. Scott L

    Scott L High Wheeler

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    How did it drive pre efi? Or did you purchase it with the efi installed?
     
  7. Mark Aycock

    Mark Aycock High Wheeler

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    I had the exact same problem after we installed the new transmission. I had bent part of the transmission linkage. When I straightened everything out with no binding, everything worked great.
     
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  8. mallen

    mallen High Wheeler

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    Is the FI system controlling timing? Could there be something wrong with the timing advance? What about the fuel pump? Maybe it cant supply enough fuel for the engine under load. (throttle plates only cracked with no load, you get enough, but wide open under load you dont...) Could the tune just be totally screwed up. What about the throttle position sensor on the FI? (I assume it has one). What sensors does it have? Perhaps it cant read one and is going into failsafe mode. (I hope it will do that, just like a factory system rather than for example, having a knock sensor go out, and rather than go into limp mode, keep advancing the timing because its not getting any indication of knock) A call to vendor for tech support might turn up something. Even if its not the case that its their equipment thats the problem, they know how their equipment reacts when something else goes wrong and may have some ideas what to check.
     
    Last edited: May 15, 2019
  9. David Banner

    David Banner High Wheeler

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    Has the vehicle ever driven right with efi hooked up?
    ie: "it was driving great yesterday, and now it don't" or what...?
     
  10. Dana Strong

    Dana Strong Dreams of Cub Cadets

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    Yes, you forgot to mention the EFI and any past history you have for the vehicle. Might have been better to start the thread in the Injection Forum too. Bill could probably give better advice than I. I can pull codes on my EFI-equipped (more modern) cars but know nothing about your system.

    If you have a steep road going up a hill and start from a stop in first gear, thereby putting a good load on it, giving it lots of gas pedal, how does it perform? That might give some information about whether it's a computer problem or caused by transmission linkage.
     
  11. walkersscout

    walkersscout High Wheeler

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    First pull the air cleaner and see if the throttle plates open all the way when you depress the accelerator. After that I would check fuel pressure.
     
  12. kylescars

    kylescars Farmall Cub

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    So after some tinkering last night I was able to figure it out, or at least partially figure it out. Last week I had installed new trans seals, including the one for the kickdown linkage. At some point in the reinstall, the kickdown and been pushed far back and got stuck there for some reason. Manually operating the throttle with my hand allowed the engine to rev up, but in drive, the linkage seemed to be binding up on the kickdown. I disconnected the kickdown completely, at which point I was able to pull the linkage forward. After coming forward, it won't allow me to push it back as far as it was. Leaving it disconnected has returned much more pedal travel and the ability to go above 1800 RPM. This also allowed for me to shift down into first gear.

    I don't know enough about the trans to say WHY this happened or what was going on internally, but this seems to have solved the problem. Looks like it's time to switch over to a Lokar setup for the kickdown!
     
  13. scoutboy74

    scoutboy74 Lives in an IH Dealership

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    I would hazard a guess that the TV linkage was bent in some unnatural manner during the seal replacement process. You're aware that driving the vehicle with that linkage disconnected is not advisable, yes? If the linkage down at the trans has been disfigured in some way, I'm not convinced that a Lokar setup would address that problem. Bent is bent whether a rod or cable is in play.
     
  14. kylescars

    kylescars Farmall Cub

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    I did not know that. Short of simply not having the ability to kickdown at WOT, what's the harm in leaving it disconnected? Everything at the trans seems fine, so my guess is if it were bent it is likely in the arm?

    Ideally I'd like to restore the kickdown function, but without any apparent bending in the linkage I think Lokar may be the best way to go, yeah?
     
  15. scoutboy74

    scoutboy74 Lives in an IH Dealership

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    That's the common misconception about the TF727. That linkage isn't just for kickdown/passing gear. It is a throttle valve linkage or TV for short. That trans needs constant throttle input in order to function properly. Operating without the linkage connected will lead to premature unit failure. Yes, if the damage is in the rod portion only, then either a replacement rod or a Lokar cable setup would fix the problem.
     
  16. kylescars

    kylescars Farmall Cub

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    Huh, very interesting! In that case I'll get the kit ordered and get it installed asap. Thanks for the heads up!
     
  17. scoutboy74

    scoutboy74 Lives in an IH Dealership

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    Sure. Is the rod so badly fooked that you couldn't massage it back into "gude enuf fer gummint werk" status, at least as a temporary get you by?
     
  18. kylescars

    kylescars Farmall Cub

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    Well that's the weird thing. Supposedly the FiTech unit is an exact match for a Holley carb, but the linkage didn't attach as before. I rigged something up that theoretically worked, but it led to the above problems (or at least contributed. At this point I don't know if the seal replacement did it, or if the linkage connection did) I can have a look at it tonight to see if it is salvageable or if there's a way to hook them back up, but in the interest of eliminating weird fixes I'll probably just make the switch.
     
  19. Dana Strong

    Dana Strong Dreams of Cub Cadets

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    In the 727, doesn't that affect pressure of the fluid which controls servos and bands, and which needs to vary depending on whether the unit is shifting or running at a steady state? Overly harsh shifting puts a strain on gears and the torque converter, while too loose allows slipping of bands, and thus unneeded wear.
     
  20. scoutboy74

    scoutboy74 Lives in an IH Dealership

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    Nailed it.
     

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