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Technical Going to get to the bottom of this damed high RPM miss.

Discussion in 'The Hokey Ass Message Board' started by 34Larry, Apr 19, 2020.

  1. 34Larry
    Joined: Apr 25, 2011
    Posts: 1,237


    81 years ago today at 7:05 PM in Helena , Montana a new soon to be "car guy", popped out, stood up and said, "floor it, I've arrived.
    I can't and won't complain a bit. There's been some flat cam days, out of gas days, but more petal to the metal days than can be counted. Life for the most part has been wonderful in spite of all the misses I've caused for myself. Three wonderful daughters, (one of them waiting in heaven for me), (2) loving wives, and my younger brother who
    I would have never made it with out, and I posse the strongest brotherly love for that, is possible.
    I've loved the car culture since about early 1947. My best friend and I could name every car a what year it was by then.
    So fast forward though 81 years>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>to this morning.
    Where to go now, what to do.
    Well as you guys know I have and rebuilt a former 34 (3) window Ford from the 50's and have my issues with it since finally getting on the road in .'17. Well it has run just okay, having brake, transmission problems and after the trans was replaced it developed a miss higher at RPM that has gotten some better but not gone away. Just running around locally it is normal unless getting into it in 1st from a light. It idles great, starts great but damn it, it ain't right. So yesterday I decided it will be fixed and running right or else. So right now the tare down has started, suspecting a vacuum leak because last time my helper installed an intake gasket that had been torn in half. But what ever it is, I'll find it and get this thing on the road like it should be.

    34larry, still on this side of the grass and turning wrenches...……………………...:rolleyes::D
    48fordnut, mctim64, Boryca and 10 others like this.
  2. Petejoe
    Joined: Nov 27, 2002
    Posts: 10,466

    from Zoar, Ohio

    loudbang likes this.
  3. BoogittyShoe
    Joined: Feb 18, 2020
    Posts: 330


    How 'bout a new set of plug wires? That's a lot easier than pullin' the manifold. Then, if that's not it, well, at least you'll have a new set of plug wires.
    loudbang and firstinsteele like this.
  4. Don't forget that a part isn't always good just because you "know" it is good; in other words don't assume.
    loudbang and Boneyard51 like this.
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  5. big duece
    Joined: Jul 28, 2008
    Posts: 5,913

    big duece
    from kansas

    A vacuum leak would give you a high idle, that is hard to settle down...
    loudbang, Baumi and Tim like this.
  6. ekimneirbo
    Joined: Apr 29, 2017
    Posts: 1,094

    from Brooks Ky

    Why not put a vacuum gage on it that you can see while driving and take a test drive......unless you can duplicate the miss in the drive way. Then maybe try pulling plug wires one at a time and see if its one cylinder missing or random cylinders.
    loudbang likes this.
    Joined: Oct 16, 2018
    Posts: 187


    “Since the trans was replaced”
    Check grounds around the bell housing area, and make sure the distributor wasn’t resting on the firewall when the trans was dropped. I don’t know what you have for an engine, so if none of this applies, my apologies...
  8. winduptoy
    Joined: Feb 19, 2013
    Posts: 1,941


    Hey Larry, Larry here....Happy Birthday you old fart!
    I always like to run the engine in the dark of night and take a good look over
    Funny what lights up from time to time
    Last time it was a spark plug that illuminated the porcelain and it ran fine at idle
    Enjoy the challenge and hope I've got your attitude at your age!
    Got to go hunt for Curly and Mo....
  9. Long shot, but you do have the coil wired correctly? They will work if wired backward, but better at low rpm and then poor at high rpms. Also agree new plulg wires can't hurt and the view at night will show any leaking. A little is OK. But a light show is bad.
    loudbang and Tim like this.
  10. Doublepumper
    Joined: Jun 26, 2016
    Posts: 607


    Last time I chased down a high rpm miss it was a loose distributor shaft allowing the points gap to fluctuate.
    Good luck, hope you find it without too much hassle and....Happy Birthday!
    loudbang and Boneyard51 like this.
  11. jetnow1
    Joined: Jan 30, 2008
    Posts: 1,533

    from CT
    1. A-D Truckers

    Can't help with the miss but anyone in their 80's driving a 34 is my hero. Happy Birthday!
  12. When a new problem shows up, go to the last thing you fixed.

    a bumped cap can mess things up. Wires can have a semi crappie terminal connection that works till you bump/brush up against it.
    Yep, and plug wires get old, look great hardly any use but just bad.
    loudbang and olscrounger like this.
  13. 41rodderz
    Joined: Sep 27, 2010
    Posts: 4,708

    from Oregon

    Happy birthday too you. :)
  14. 31 5w
    Joined: Aug 6, 2010
    Posts: 107

    31 5w

    Happy B-Day, 68 yrs. ago today I popped out also! Been great most of time, survived brain surgery 32 yrs. ago and retired 6 yrs now. Been blessed w/ my 32+ "bonus yrs." If I make it to 70 I will have lived as many yrs. Post surgery as before.
    loudbang likes this.
  15. 41 GMC K-18
    Joined: Jun 27, 2019
    Posts: 1,011

    41 GMC K-18

    Happy Birthday to you Larry !
    Be safe in everything that you do!
    Don't move while the room is in motion!
    BE SAFE (2).JPG
    Last edited: Apr 19, 2020
    loudbang likes this.
  16. Well; Happy Birthday!
    loudbang and 41 GMC K-18 like this.
  17. rockable
    Joined: Dec 21, 2009
    Posts: 2,904


    Remember, the engine torques to one side when you load it hard. (DS, I believe.) Could you be momentarily shorting a wire against the engine under acceleration? I had that problem once, where the wire was intermittently touching the exhaust manifold. Good luck!
    loudbang and 41 GMC K-18 like this.
  18. borderboy1971
    Joined: Oct 20, 2008
    Posts: 688

    from Canada

    Happy bday Larry. I respect your dedication to find that miss.
    loudbang likes this.
  19. boutlaw
    Joined: Apr 30, 2010
    Posts: 1,218


    Happy Birthday Larry, Im behind you by 9 and hope Im doing what youre doing at your age. Good ideas provided so far, especially looking back at last work, but I tend to think ignition as well, seems a vacuum leak would cause different symptoms than a high RPM miss. Regardless, I have no doubt youll find the problem and post the fix. You didn't mention whether electronic or points ignition, I assume electronic, which to me is easier to troubleshoot. Points and condensers are becoming more difficult to find, especially a quality condenser. My RPM misses seem to always be rotor/cap related, even the MSD caps and rotors are not quality any more, and high energy ignition systems seem to find the flaws in each.
    loudbang likes this.
  20. catdad49
    Joined: Sep 25, 2005
    Posts: 4,162


    Happy Birthday, Larry! Where are you going in such a hurry?
    Last edited: Apr 20, 2020
    loudbang likes this.
  21. Hardest to find problem I ever had was on a '57 Bird. Turned out to be a busted diaphragm in the distributer vacuum advance unit. Good luck and be sure to tell us what you find.

    Charlie Stephens
    loudbang likes this.
  22. cheepsk8
    Joined: Sep 5, 2011
    Posts: 554

    from west ky

    Here is something worth a try. An old guy taught me to work on my cars way back when. I had a 327 that would only cut out on high rpms and on kickdown when the motor was under load. This went on for a long time but the miss never crept down into the normal driving rpms. Finally I asked him about it and he handed me a new coil wire. The boot insulation must have been compromised. Problem solved.
    tb33anda3rd and loudbang like this.
    loudbang likes this.
  24. I have been chasing a miss for a long time.
    Msd distributor pick up went bad. Ohm test showed it as proof. Still missed.
    The light on the msd box was flashing. Swapped coils worked better. Still misses.
    Ran the numbers on the holley carb. This carb was brand new. Front and rear metering plates were backwards. Runs better still misses.
    After I got lit up setting the timing grabbing the dist cap I figured something was up. I changed the cap rotor and wires with new top of the line msd parts. Runs great. It is now a tire frying car.
    Sometimes it's more that one thing stacked up that makes it hard to sort out.
  25. chargin03
    Joined: Jan 8, 2013
    Posts: 429


    Happy Birthday !
    loudbang likes this.
  26. gene-koning
    Joined: Oct 28, 2016
    Posts: 1,818


    Didn't you lift the body off the car to fix the transmission behind that Hemi?
    I think I would be looking towards a missed ground, or a wire with a broken or skinned insulation, or a loose wire or a bad electrical connection in the ignition primary system. Something (or anything) that could have happened when the body was reinstalled.
    I don't believe a vacuum leak will give you a high rpm miss, but strange things do happen. Gene
    Joined: Dec 3, 2002
    Posts: 1,113


    Happy Birthday and I have no doubt you'll find the problem! And really that's part of the fun.
    loudbang likes this.
  28. Boneyard51
    Joined: Dec 10, 2017
    Posts: 4,015


    I put a new set of “ good” spark plug wires on a ot car one time and it ran bad! Checked everything..... put another set of different brand wires on.... ran great! Brand new set was junk, from the very start! And that was a long time ago! Things are worse now!

    PhilA, Desoto291Hemi and loudbang like this.
  29. Baumi
    Joined: Jan 28, 2003
    Posts: 2,421


    I was chasing a higher rpm ( above 4k) miss for years until the coil went and the car would not start anymore. With the new coil the high rpm miss was gone ...
    Happy birthday, Larry!
  30. loudbang
    Joined: Jul 23, 2013
    Posts: 29,063


    Happy birthday old rodder. :rolleyes:
    Roothawg, winduptoy and catdad49 like this.

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