455 has begun to bog with any throttle

Discussion in 'Street/strip 400/430/455' started by TheCynic, Dec 9, 2019.

Page 3 of 9
  1. TheCynic

    TheCynic Smack Talker

    Alright will do. Gonna have to get one of these guys to show up. Ill bribe em w beer. These spark plugs are stuck in like a MFer right now so this is fun....
     
    TheCynic, Dec 11, 2019
    #41
  2. TheCynic

    TheCynic Smack Talker

    Its a 67. Let me find my meter and ill try to figure that out. Never was great w the electrical haha. Ive kept a battery tender on and its quite a new battery so hope thats not the issue
     
    TheCynic, Dec 11, 2019
    #42
  3. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Well, you might as well change them. Whoever put them in over tightened them. 1/16th of a turn after finger tight. They should come out easy.

    On an HEI cap, the 12 volt feed clips into the cap. Unclip it and hook a meter red lead to the wire you unclipped from the cap, black lead to engine ground. Turn the key on to run, you should see 12 volts on the meter. Have someone continuously crank the engine. The meter should drop down to 9 or 10 volts and be steady.
     
    LARRY70GS, Dec 11, 2019
    #43
  4. 1972Mach1

    1972Mach1 Just some M.M.O.G. guy.....

    If they are in that tight, who knows how long they've been in there. Might just be fouled plugs. They were probably borderline and when it drank the coolant it probably just finished the job for a few of them and now it won't fire.
     
    1972Mach1, Dec 11, 2019
    #44
  5. 436'd Skylark

    436'd Skylark Sweet Fancy Moses!!!!!

    Im thinking if it's a new harness it's not wired properly for the HEI. Maybe the resistor wire is burned out and it's only getting 12v in the crank position from the wire coming from the starter..
     
    436'd Skylark, Dec 11, 2019
    #45
  6. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Agreed, the HEI won't run through a resistor wire for very long if at all. If it did run, the reduced spark may have resulted in plug fouling especially with a Holley DP.
     
    LARRY70GS, Dec 11, 2019
    #46
  7. TheCynic

    TheCynic Smack Talker

    Thanks guys ill give these things a shot as soon as im able. Is it alright to put any blaster on the plugs to get em loose?
     
    TheCynic, Dec 11, 2019
    #47
  8. johnriv67

    johnriv67 Well-Known Member

    PB Blaster? Yes
     
    johnriv67, Dec 11, 2019
    #48
  9. TheCynic

    TheCynic Smack Talker

    Looks like the other way around unless i did some dumb sh!t. Got 3.9 w key in and shot up to 11.whatever went too fast when my gf gave it a crank. It sounded weak tho and the battery had sat for about 2 weeks now so im gonna put the tender back on overnight and see again.

    Regarding the wire coming into the distributor i do have some memory now of adding a few connections in to match the pre existing setup, and again, this configuration ran for about 3 years as well without issues until this new overheating business id had. Thanks again fellas
     
    Last edited: Dec 12, 2019
    TheCynic, Dec 12, 2019
    #49
  10. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    3.9?? When did it shoot up to 11? When the engine was cranking?
     
    LARRY70GS, Dec 12, 2019
    #50
  11. TheCynic

    TheCynic Smack Talker

    Yes. It was at 3.89 in run or on or whatever and went from 7 to 9 to 11 all pretty quickly under cranking before i i had her cut it
     
    TheCynic, Dec 12, 2019
    #51
  12. johnriv67

    johnriv67 Well-Known Member

    And there is your problem. 3.9 in "run" will not work
     
    johnriv67, Dec 12, 2019
    #52
  13. TheCynic

    TheCynic Smack Talker

    Seems like. Thats why i put the tender back on. Although even still last week before the battery had sat a bit it was doing this so im not sure ive quite solved it yet. Something somewhere else is screwed up?
     
    TheCynic, Dec 12, 2019
    #53
  14. TheCynic

    TheCynic Smack Talker

    Also fwiw i hadnt yet checked the plugs or vacuum. Was going to test this 12v first Larry had mentioned at the time
     
    TheCynic, Dec 12, 2019
    #54
  15. johnriv67

    johnriv67 Well-Known Member

    Either your alternator has stopped charging and when running the car you are just draining the battery, or your 12v connection to the coil is not in fact 12v, which would make it run poorly at best, if at all.
     
    johnriv67, Dec 12, 2019
    #55
  16. TheCynic

    TheCynic Smack Talker

    Ok ill keep looking more into figuring this issue out here then. Its odd because it had actually been running fine... Weird.
     
    TheCynic, Dec 12, 2019
    #56
  17. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    From what I can tell, the problem is you replaced the engine harness. That replacement harness is for a points system, not the later GM HEI. The HEI requires full time battery voltage. The points require reduced voltage in run so that they last.

    This is how the stock points system works. Extending from the firewall engine harness connector(below the brake booster), is a calibrated length of special resistance wire. This wire does not extend all the way to the positive side of the coil. In the harness, it is joined by a yellow wire leading from the "R" terminal of the starter solenoid, and from there, it extends to the positive side of the coil. There is a shorting switch inside the starter solenoid. When the starter motor is cranking the engine to start, the shorting switch inside the solenoid, sends battery voltage through the yellow wire to the coil positive, effectively bypassing the resistance wire. Once the engine starts, and the key is released to the run position, the yellow wire ceases to supply voltage, and voltage flows from the firewall via the resistance wire. This drops the running voltage so that point life is maximized.

    See what is happening? When cranking, you are getting full battery voltage through the starter bypass wire, but when you release the key, the voltage is cut down. I'm surprised the HEI ever ran like that. It probably dropped the spark enough to foul your plugs and now the engine won't run at all. Your coolant leak was probably just coincidental. You also had a carburetor flooding problem which didn't help. Look at your plugs, they are probably fuel fouled (black)
     
    Last edited: Dec 12, 2019
    LARRY70GS, Dec 12, 2019
    #57
    TheCynic and johnriv67 like this.
  18. johnriv67

    johnriv67 Well-Known Member

    He's called the Wizard for a reason, I didn't even think the plugs could have fouled, now that explains why nothing works.
     
    johnriv67, Dec 12, 2019
    #58
    TheCynic likes this.
  19. TheCynic

    TheCynic Smack Talker

    Will do. Thanks. Im gonna have my electrical guy come thru this weekend and see about wiring it up correctly. Could this have made my engine run hot as well? Seems like.

    Honestly i cant for the life of me remember which harness i ordered from M&H so it probably was the wrong one, but, i thought we made the edits where necessary to match up to the pre-existing setup that was there when i i bought it. Either way, thanks for all the help.
     
    TheCynic, Dec 12, 2019
    #59
  20. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Unless you specifically told M&H that you did NOT have points, but an HEI, they gave you a harness meant for points. All you need to do is replace the resistance wire with regular wire. That way, the HEI will get full voltage.

    If you want, you can run a wire directly from the + battery terminal to the distributor. See if the engine will start and run like that. You'll need to pull the connection to shut the engine down, but it is only meant to temporarily check our theory here.

    http://v8buick.com/index.php?thread...ystem-function-tests-and-modification.248990/
     
    LARRY70GS, Dec 12, 2019
    #60
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