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Problem going up hills (highway)

Discussion in 'Early CJ5 and CJ6 Tech' started by nhjeep, May 23, 2010.

  1. May 23, 2010
    nhjeep

    nhjeep NH Jeep

    NH
    Joined:
    Mar 6, 2008
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    113
    I have a 1969 CJ5 with a 225. I have a DUI distributor, new plugs gapped to .55, rebuilt carb, new plastic tank (under the seat), new sending unit, new fuel pump, and new fuel filter. The engine has great compression and does not skip. The engine is strong only 30,000 miles on it. Timing is on and all the plugs are good. It runs great on the road on flat ground, but when I attempt to go up a long hill it has a hard time climbing the road. It spudders and bucks and appear to not be firing the fuel, if you down shift to second it goes good again seems to get you up the hill but them it will start happening in second as well. It did this before I replaced the carb. Any ideas would be great.
    Thanks in advance
     
  2. May 23, 2010
    Walt Couch

    Walt Couch sidehill Cordele, Ga. 2024 Sponsor 2023 Sponsor 2022 Sponsor

    cordele, Ga.
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    What is your temp gauge showing when climbing a long steep grade when it starts sputtering and bucking? Did you blow air thru your fuel line before putting in new tank and fuel pump? What is your initial timing set at @550-650 RPM with vacuum adv hose removed from dist and plugged?
     
  3. May 23, 2010
    nhjeep

    nhjeep NH Jeep

    NH
    Joined:
    Mar 6, 2008
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    I have not checked the temp, what should it be at? I did not blow air before putting the tank and fuel pump on. I'll have to check the RPMs. I do some checking
    Thanks!
     
  4. May 30, 2010
    Dan66cj5

    Dan66cj5 Member

    Oregon
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    Feb 20, 2003
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    235
    Could it be that your carb float level is too low ? Shutting off fuel too soon and starving your motor
     
  5. May 30, 2010
    77CJ5

    77CJ5 New Member

    USA
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    May 30, 2010
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    ..
     
    Last edited: Feb 23, 2011
  6. May 31, 2010
    colojeepguy

    colojeepguy Colorado Springs

    At the foot of...
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    It sounds like a weak fuel pump or plugged fuel filter to me. On a long grade, fuel demand is high and you're running out of gas. Down shifting gives the pump a momentary respite to catch up, but then the same thing happens when you get on the throttle again.
     
  7. May 31, 2010
    Walt Couch

    Walt Couch sidehill Cordele, Ga. 2024 Sponsor 2023 Sponsor 2022 Sponsor

    cordele, Ga.
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    Also a bad PCV valve will rob you of power.
     
  8. May 31, 2010
    lynn

    lynn Time machine / Early CJ5 HR Rep Staff Member

    Huntingdon PA
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    I've seen this in older carbed SBCs. Idled fine, reved fine, but couldn't drag the rig up a hill.
    I'm voting fuel pump.
     
  9. May 31, 2010
    1960willyscj5

    1960willyscj5 Well-Known Member

    Mesa, Arizona
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    2,793
    Do the simple stuff first.
    Check fuel lines and fuel filters. Do you have a filter between the tank and the fuel pump?
    Do you have one on the inlet to the fuel bowl on the carb also?

    Half way plugged fuel filter will do this.:hurrican:
     
  10. May 31, 2010
    nhjeep

    nhjeep NH Jeep

    NH
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    Mar 6, 2008
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    I replaced the fuel pump with a brand new and still had the same problems. There is no filter from the tank to the tank and the pump, but there is one after the pump to the carb. Brand new fuel filter also. I am going to have to try some of the fixes above, everyone seems to think it's a fuel issue as do I. Hoperfully I get it squared away this week. Can the steel fuel lines get clogged up if they are 40 years old.
    Thank's everyone for the help,
     
  11. May 31, 2010
    alex211

    alex211 Member

    Pennsylvania
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    Aug 25, 2009
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    441
    Maybe your total advance is too far.
     
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