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Fixed: V6 Cutting out at cruising speeds?

Discussion in 'Early CJ5 and CJ6 Tech' started by sparky, May 14, 2006.

Page 3 of 50
  1. jpflat2a

    jpflat2a what's that noise?

    Re: V6 Cutting out at cruising speeds?

    one bad exhaust valve wouldn't/shouldn't cause what he's describing IMO
    rough idle, yes
    spitting out the ex pipe, yes
    no power in 3rd gear, I don't think so
    wish I was closer....
     
    jpflat2a, May 15, 2006
    #41
  2. fourtrail

    fourtrail Built not Bought

    Re: V6 Cutting out at cruising speeds?

    Tripple check power to the dist. if need be run new wire from the batt to the dist to be sure you have full voltage. I have seen a connector go bad and not give full voltage and when you hit 3rd it doesn't have enough voltage to create good spark. also what does the voltmeter say when it starts cutting out?
     
    fourtrail, May 15, 2006
    #42
  3. sparky

    sparky Sandgroper Staff Member Founder

    Re: V6 Cutting out at cruising speeds?

    I wasn't attributing this to one bad valve, just saying I have 1 known valve problem, therefore it'll need to be torn down.
     
    sparky, May 15, 2006
    #43
  4. Glenn

    Glenn Kinda grumpy old man Staff Member

    Re: V6 Cutting out at cruising speeds?

    I agree 100%. I just meant the vacuum reading is already not going to be steady because of that.
     
    Glenn, May 15, 2006
    #44
  5. sparky

    sparky Sandgroper Staff Member Founder

    Re: V6 Cutting out at cruising speeds?

    Ok, good to know that too.
     
    sparky, May 15, 2006
    #45
  6. Glenn

    Glenn Kinda grumpy old man Staff Member

    Re: V6 Cutting out at cruising speeds?

    I should have said that with my understanding of the expected results the reading won't be steady.
     
    Glenn, May 15, 2006
    #46
  7. sparky

    sparky Sandgroper Staff Member Founder

    Re: V6 Cutting out at cruising speeds?

    Oh, I knew I had the exhaust valve issue before any of this started. You could feel it suck your hand up against the tailpipe and you can hear it on the passenger side that it's not running evenly.

    I'm gonna go through all this and it's gonna be something stupidly simple. :rofl:
     
    sparky, May 15, 2006
    #47
  8. jpflat2a

    jpflat2a what's that noise?

    Re: V6 Cutting out at cruising speeds?

    I hope you're right :)
     
    jpflat2a, May 15, 2006
    #48
  9. Glenn

    Glenn Kinda grumpy old man Staff Member

    Re: V6 Cutting out at cruising speeds?

    I don't remember what all you wrote, but I'm assuming you've had the valve covers off and inspected the obvious?
     
    Glenn, May 15, 2006
    #49
  10. sparky

    sparky Sandgroper Staff Member Founder

    Re: V6 Cutting out at cruising speeds?

    Nope, I got tired of dealing with it yesterday and walked away from it.

    To me nothing was "obvious" yesterday. I thought it was timing, then fuel related, now valves. :?
     
    sparky, May 15, 2006
    #50
  11. lynn

    lynn Time machine / Early CJ5 HR Rep Staff Member

    Re: V6 Cutting out at cruising speeds?

    Checked for stuck/collapsed lifter? (Run some MMO in the oil for awhile)
     
    lynn, May 15, 2006
    #51
  12. sparky

    sparky Sandgroper Staff Member Founder

    Re: V6 Cutting out at cruising speeds?

    Ack! I hope not. I did that when I brought it home before I changed the oil last fall and then after my oil pump gave up the ghost on me. Mobile1 10w30 in it now. That should clean it out pretty well too...

    If it was A lifter then why are both sides chuffing and wouldn't I hear it at idle ticking?
     
    sparky, May 15, 2006
    #52
  13. lynn

    lynn Time machine / Early CJ5 HR Rep Staff Member

    Re: V6 Cutting out at cruising speeds?

    I was just shooting for a simpler solution... :?
    Yep the mobil 1 should clean it out too. And it would only be on one side

    Any chance your dist cap isn't seated correctly? Last fall mine would idle fine but miss and backfire under anything more tha light load load... the hold-downs on the dist cap had lost spring tension.
     
    lynn, May 15, 2006
    #53
  14. sparky

    sparky Sandgroper Staff Member Founder

    Re: V6 Cutting out at cruising speeds?

    Doubtful, I've had the cap off and back on several times adjusting the vacuum advance and it did it with MOP's Delco as well.

    To recap the symptoms. It runs fine under a heavy load until I put it in 3rd gear. 1rst and 2nd it runs over 2500 RPM fine. It won't go over 2500 RPM in 3rd. Puffing, and chugging as if it's not getting fuel or air or spark? Not backfiring at all.
     
    sparky, May 15, 2006
    #54
  15. jzeber

    jzeber Well-Known Member 2022 Sponsor

    Re: V6 Cutting out at cruising speeds?

    It runs fine under a heavy load until I put it in 3rd gear. 1rst and 2nd it runs over 2500 RPM fine. It won't go over 2500 RPM in 3rd. Puffing, and chugging as if it's not getting fuel or air or spark? Not backfiring at all.

    Does it matter what speed??
     
    jzeber, May 15, 2006
    #55
  16. sparky

    sparky Sandgroper Staff Member Founder

    Re: V6 Cutting out at cruising speeds?

    What speed when? I can't go any faster than 50-55 in 3rd since it won't go past 2500 RPM. But it will get up to that speed in 2nd gear.
     
    sparky, May 15, 2006
    #56
  17. timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Re: V6 Cutting out at cruising speeds?

    You're not simply running out of power at 55? There's a big difference in wind resistance between 55 and 35, like 250%.
     
    timgr, May 15, 2006
    #57
  18. sparky

    sparky Sandgroper Staff Member Founder

    Re: V6 Cutting out at cruising speeds?

    I've frequently driven this Jeep at 70 mph with the ability to go faster that I've not done. This is not normal. That and the bucking and chugging.
     
    sparky, May 15, 2006
    #58
  19. timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Re: V6 Cutting out at cruising speeds?

    Well, yeah, what I mean is that you're down on power generally - there's nothing special about 3rd gear. However, a '71 might have transmission controlled spark (TCS) which cuts the vacuum advance in 3rd. There would be a shift-rail activated switch going to a solenoid on top of the engine. TCS was present in CA in '73, maybe 71-72 too.
     
    timgr, May 15, 2006
    #59
  20. beeser

    beeser Member

    Re: V6 Cutting out at cruising speeds?

    I don't have the smarts to offer advice of my own except to pass along the list of possible reasons for lack of power out of the FSM.

    Low compression
    Ignition system (timing late)
    Improper functioning carb or fuel pump
    Fuel lines clogged
    Air cleaner restricted
    Engine temperature high
    Valves do not seat properly
    Intake manifold or cylinder head gasket leak
    Muffler or exhaust pipe clogged or bent
    Spark plugs dirty or defective
    Ignition coil or capacitor defective
    Electirical connection loose
    Broken valve spring
    Broken piston ring or piston
    Cyhlinder head gasket defective
    Distributor cap cracked

    Here's one thought of my own though. You said the fuel filter was clean but do you know the fuel line itself isn't partially clogged or restricted somewhere?
     
    beeser, May 15, 2006
    #60
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