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Driving Uphill From A Dead Stop.....quite Sluggish

Discussion in 'Early CJ5 and CJ6 Tech' started by ronnie victor, Mar 7, 2019.

  1. Mar 7, 2019
    ronnie victor

    ronnie victor Member

    raleigh, nc
    Joined:
    Jun 29, 2015
    Messages:
    124
    Folks -- one of my concerns is that my 1966 F4 engine is really hard to get moving when pulling away from a stop sign or red light and having to go up a city street grade. If the engine is rather cold (running only about five minutes in this season), it's a real struggle to break 20 mph in second gear and that seems to me that I'm stressing the little engine. When engine is adequately warmed up, I might be able to up shift to third at 25 mph up a city grade, but that's close to lugging the engine and I will often down shift to reach top of the grade.

    Seems to me that years ago when my CJ5 and I were both a lot younger, uphill sluggishness around a city was not a concern. But I let Mr. CJ sit idle for 20+ years before doing the work a few years ago that was needed to get it road worthy again. It's tuned and timed fine (about 1500 miles ago), the idle is great, and acceleration on a flat is great. And if I come down a hill at 40-45 mph, I can easily make it up the other side (city streets), even getting a little acceleration on the up hill (and, oh, that feels good......holding my own against the following traffic :)

    My question is: what areas of the engine should I investigate for achieving better uphill acceleration, cold and warm engine? For example: re-check the 5BTC timing, buy new ignition cables, recheck 0.20" point gap, clean plugs every few 100 miles?? I have not checked the compression. As a reference, I get about 15 mph (ethanol free gas) in city, and seem to go through a little more engine oil than I would like (no smoking though).

    Please offer your opinions about how to improve uphill acceleration driving an F4-135 .... thank you, Ron
     
  2. Mar 7, 2019
    PeteL

    PeteL Member 2020 Sponsor 2019 Sponsor

    Hills of NH
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    Aug 3, 2003
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    A compression check is easy, and a vacuum check even easier. Both gauges are extremely affordable.

    Any rational diagnosis should start only after points and timing are verified and set to specification.

    15 mpg is about right.

    Is your air filter clean? Brakes not dragging? No squirrels in the muffler?
     
    dozerjim likes this.
  3. Mar 7, 2019
    colojeepguy

    colojeepguy Colorado Springs 2019 Sponsor

    At the foot of...
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    Apr 4, 2010
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    :lol:
    That's actually a good thought....if it sat a long time, critters could have nested in the muffler or tailpipe and partially plugged it.
     
    Alan28 likes this.
  4. Mar 7, 2019
    mike starck

    mike starck Member 2019 Sponsor

    salem,oregon
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    Jun 22, 2006
    Messages:
    653
    One other suggestion besides exhaust restriction and dragging brakes(froze-up wheel cylinders) is the centrifugal advance in distributor.Verify that it is functioning beyond just checking initial timming.
    Good luck with it. mike
     
    PeteL likes this.
  5. Mar 7, 2019
    jeep2003

    jeep2003 Active Member

    Vestal NY
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    May 30, 2006
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    did you check the valve clearances? a leakdown test is much more usefull than a compression check
     
  6. Mar 7, 2019
    PeteL

    PeteL Member 2020 Sponsor 2019 Sponsor

    Hills of NH
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  7. Mar 7, 2019
    Jw60

    Jw60 Recovering Jeepaholic

    Sedalia MO.
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    Oct 5, 2018
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    Check for limited fuel flow there is a process to check the mechanical pump performance.

    Now that just ain't right.
     
  8. Mar 7, 2019
    ronnie victor

    ronnie victor Member

    raleigh, nc
    Joined:
    Jun 29, 2015
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    124
    Thanks for your inputs, Everyone. Ha, ha.. no animals in exhaust. Put in entire system during restoration (purchased from Walcks). Wheel cylinders all new (brake lines too). But I can easily recheck the brake adjustments. Vacuum check two years ago was at low end, I believe. About 17 at some port beneath carb.

    Looks like I need to check compression (I have gauge), do a leak down ( have never done), and check centrifigal advance in distributor ( have never done). Need to do some reading on these latter two. Homework! ( I like the road sign, PeteL )
     
  9. Mar 7, 2019
    62CheepJeep

    62CheepJeep Member

    Spartanburg SC
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    Sep 10, 2018
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    Please post what you find out about the centrifugal advance? I am curious.
     
  10. Mar 7, 2019
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    Sep 21, 2002
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    9,277
    How about accelerator linkage adjustment? Does the pedal bottom out before the throttle plate is fully open?
     
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  11. Mar 8, 2019
    62CheepJeep

    62CheepJeep Member

    Spartanburg SC
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    Sep 10, 2018
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    Is it possible the parking brake on the transfer case is dragging or pulled on?
     
  12. Mar 8, 2019
    Howard Eisenhauer

    Howard Eisenhauer Super Moderator Staff Member

    Tantallon, Nova...
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    BTDT.
     
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  13. Mar 8, 2019
    70cj5134f

    70cj5134f Member

    East Tn
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    Shorter tires would improve up hill power.
    You can advance timing to 10 btdc, with a good tune and good gas.
    I live in the hills of east TN, lots of 2nd gear,25-30 mph back road driving.
     
  14. Mar 8, 2019
    matt johnson

    matt johnson Sponsor

    chesapeake, va
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    PeteL likes this.
  15. Mar 8, 2019
    Alan28

    Alan28 Well-Known Member 2020 Sponsor 2019 Sponsor

    Ch√Ętillon en...
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    I have the Hurricane engine. When old he was hard to get power. Then we cleaned the carburetor, change the spark plug, fix well the ignition point, fix well the carb .... AND now cold or hot weather I have full power. The work on the carb is to make at theend when all is clean and correct. It must be adjusted carefully then...it Works!

    Of course there are many other reasons to a lack of power, valves, bad compression, keeping the foot on the brakes when driving :p but first things first, check the carb.
     

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