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Strange no start

Discussion in 'Early CJ5 and CJ6 Tech' started by beeser, Jan 13, 2012.

  1. Jan 13, 2012
    beeser

    beeser Member

    Arizona
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    I've had my '70 CJ5 (V6) stored in a barn for the past 9 months. While trying to start it a couple of weeks ago I couldn't get it to run without pouring gas or starting fluid in the carburetor and even then it would only run for a brief period of time. I figured there was a problem with the fuel system so I replaced the fuel pump and the canister type fuel filter. I know now I'm getting fuel up to the carburetor. Because the battery needed a boost from all of the starting attempts I hooked up a charger but inadvertently made the connections backwards. It was only on this way for a few seconds before I noticed the mistake. Now I can't get the engine to fire even after pouring gas/starting fluid in the carburetor. I'm getting a spark (maybe a week one) at the spark plug wires and out of the coil. Is it possible that I fried something in the ignition circuit? Condenser? Coil?
     
  2. Jan 13, 2012
    Walt Couch

    Walt Couch sidehill Cordele, Ga. 2020 Sponsor 2019 Sponsor

    cordele, Ga.
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    Possible = yes. What ignition system do you have installed? Are you running a tach etc.?
     
  3. Jan 13, 2012
    beeser

    beeser Member

    Arizona
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    I have a Delco distributor (not HEI), changed from the previous Prestolite. Yes, I have a tach.
     
  4. Jan 13, 2012
    Petesponies

    Petesponies Banned

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    If you are getting a spark, anything, then you have not burned anything out, meaning no open circuit. So you still have points . . how do the contacts look? If the condenser is toast, your point contacts will degrade very quickly. Do you have a VOM ?
     
  5. Jan 13, 2012
    beeser

    beeser Member

    Arizona
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    Yes, I have a VOM. Strange, the Jeep ran great before it was put into storage. I had to prime the carburetor by pouring some gas into it sometimes if it sat idle for a couple of months. Otherwise it started and ran great. Again, I was able to get the engine to fire after 9 months of storage but now it won't even do that after putting on the battery charger cables incorrectly. I'm heading out to my property next week where the Jeep is located and would like to bring along whatever you guys think I might need replacing. Parts are easier to find here in San Diego.
     
  6. Jan 13, 2012
    PeteL

    PeteL Member 2020 Sponsor 2019 Sponsor

    Hills of NH
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    Ditto on clean and adjusted points.

    Then, go back to basics. In the beginning it sounded like a fuel problem, and now seems possibly located in the carb. Stuck or blocked float-valve for instance?
     
  7. Jan 13, 2012
    beeser

    beeser Member

    Arizona
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    Maybe but wouldn't it at least fire momentarily by some gas or starting fluid poured directly into the carb? It did before hooking up the battery charger backwards. I'm leaning in the direction of something electrical amiss.
     
  8. Jan 13, 2012
    Walt Couch

    Walt Couch sidehill Cordele, Ga. 2020 Sponsor 2019 Sponsor

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    You have the standard ignition which means it would actually run if a charged battery was accidentally connected as positive ground. Wouldn't run great because the coil would be backwards but run none the less. The tach however is polar sensitive and could be causing a high resistive reading on its connection to the - (neg) terminal of the coil. Disconnect this wire just in case. Continue with the fuel and carb repair as members have stated above. HTH
     
  9. Jan 13, 2012
    homersdog

    homersdog Tulsa, Ok 2019 Sponsor

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    Beeser: I have a 71 with the v6, delco distributor. I often go several weeks when I don't have a chance to start the jeep. When it sits for a while I some times get a stuck float. just tapping on the side of the carb usually gets it unstuck. I also have a tendancy to flood it by choking it too long when I know it will be a tough start. If it was me I would:
    1)Get the battery charged back to full.
    2) pull off the air cleaner.
    3) look down thru the carb (I assume you have the rochester 2-barrel) and pump the throttle linkage by hand once or twice while looking in the carb expecting to see 2 streams of gas from the accelerator pump. this indicates at there is some fuel in the carb.
    4) If there is fuel, then try starting it with very little choke, just enough to get the throttle on the high speed idle setting.
    5) if there is NO fuel in the carb, then crank the engine for a while ( I assume you have the AC mechanical fuel pump still) to put fuel in the carb, repeat the throttle pump test. If still no fuel then somethings amiss in fuel delivery.

    6) I would also verify the voltage of battery, check to make sure the spark is Blue. If it is yellow, then it maybe a bad coil.
    7) as for what I would take if I were in your shoes: a can of gas, a carb kit ( in case you need to peek inside the carb, you'll need to replace the top gasket), a battery, coil, points/condenser, spark plug gap gauge, jeep universal shop manual (or chiltons or haynes), timing light, distributor cap and rotor, dwell meter, 5/16" id fuel hose, starting fluid. Also maybe a spool of 16 gauge wire in case something is fried on the primary side of the ignition coil.

    Good luck, Hope I didn't confuse you.
     
  10. Jan 13, 2012
    homersdog

    homersdog Tulsa, Ok 2019 Sponsor

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    Oh and one more thing. If it is stored in an area with lots of humidity you could have had some moisture collect and pool in the bottom of the fuel tank. When you cranked it starting fluid or manually pouring gas in it you may have filled the carb with water. You might want to take a look in the carb, the water will be sitting in a pool under the fuel in the carb's bowl.
     
  11. Jan 13, 2012
    PeteL

    PeteL Member 2020 Sponsor 2019 Sponsor

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    "wouldn't it at least fire momentarily by some gas or starting fluid poured directly into the carb?"

    Maybe. But it would be easy to flood it out and/or foul the plugs, especially if the spark was weak.
     
  12. Jan 13, 2012
    Petesponies

    Petesponies Banned

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    One thing you do not want to do is just guess and mix ignition problems with fuel problems. It ran by priming the venturi before, it will again if everything in the ignition system is working properly. You need to check carefully to see if you have any spark. I was suggesting a VOM because you can check the continuity through the primary winding as well as its resistance. I have seen a couple people mention about the tach. If you have a tach that is connected in series, thus all the ignition power going through the primary circuit goes through the tach as well, you could damaged it. If that happens, you have no ignition system, because power will never reach the positive side of the coil. So let that be test #1.. Turn the ignition on, make sure the points are closed and check the voltage at the positive side of the coil, attach the red lead to this terminal and the black lead to a good known ground. If you have no voltage, and have a series tach . . there's your problem. Now if your tach is a parallel tach, then the condition of the tach will in no way effect your primary ignition.If you are getting power to the coil, then move inside the distributor. Turn off the ignition switch and check to see that you have continuity through the points and condenser. Set your VOM on continuity if you have that feature or set it on resistance. Touch the movable arm of the points. With the points closed you should have continuity or basically no resistance. Then open the arm and the continuity should go away or you should read infinite resistance. If this passes, then check the coil itself as I mentioned first. Check the resistance from the positive terminal to the negative terminal. It should be a readable resistance somewhere in the 1.5-3.0 ohms range. I do not know the specs of the coils the Jeeps used; I'm a Mustang guy :) I think if you do these things, you will find out whether or not you have an ignition problem.
     
  13. Jan 14, 2012
    beeser

    beeser Member

    Arizona
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    Aside from something electrical, flooding seems like a possible cause. Although the Jeep sat overnight and it still wouldn't fire. And is it even possible to flood a carburetor using starting fluid?
     
  14. Jan 21, 2012
    Walt Couch

    Walt Couch sidehill Cordele, Ga. 2020 Sponsor 2019 Sponsor

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    Beeser did you find out what your problem is yet? We jeepers hate to see a rig down too long.
     
  15. Feb 9, 2012
    beeser

    beeser Member

    Arizona
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    Well, those that thought it was a flooding problem were correct. After pulling off the top cover of the carburetor the problem was obvious. The plastic float had broken apart and the seal around the power piston had partially disintegrated. With nothing to stop the flow of gas from the fuel pump no wonder the carb was flooded. After a quick rebuild of the carb the engine started right up. All I have to do now is fine tune it. Strange that the float and seals were in the shape that they were after only about 5 years since the carb was last rebuilt. Is it because of the alcohol and additives found in gas today?
     
  16. Feb 9, 2012
    lynn

    lynn Time machine / Early CJ5 HR Rep Staff Member

    Huntingdon PA
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    I've heard various stories of problems caused by ethanol in the fuel. I've only experienced this with lawnmowers... fuel line deteriorated from the ethanol fuel and plugged things up.
    I guess it could have been a similar problem with your carb.

    Glad to hear you you got your engine running Beeser. :tea:
     
  17. Feb 9, 2012
    beeser

    beeser Member

    Arizona
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    Oh, and thanks everyone for the tips and suggestions. Fortunately I had another float from a spare carburetor since the carb kit didn't come with one. The replacement was brass. Hope it lasts longer than the plastic one.
     
  18. Feb 9, 2012
    homersdog

    homersdog Tulsa, Ok 2019 Sponsor

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    I had the same problem with a plastic float 30 years ago, when ethanol was just starting to be widely used. Something caused the float to lose its' buoyancy, I always suspected the ethanol. I put a brass float in and it is still working just fine. I don't think the plastic float is being made anymore for the rochester 2G.
     

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