Cold/Loosing Spark Plug Fire on Cylinders-Blown Alcohol Hemi

Discussion in 'PSI Superchargers Tech Questions' started by Blown5402, Sep 18, 2013.

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  1. TOL

    TOL Active Member

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    Is this a completely new engine deal that's been put together and being run for the first few times, or has it already proven to run well in a prior life?
     
    #21
    TOL, Sep 20, 2013
  2. Mike Canter

    Mike Canter Top Dragster
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    Oil without metal particles in it is non-conductive. Oil is actually used as a insulator in high voltage applications. At this point it is worth trying anything but just don't see why a mag would cause carbon tracking on the outside of the plug insulator. The reason the EGTs are going cold is that the plug is not firing because the high voltage spark has found a path to ground that is less resistance than jumping the plug gap. Same thing inside the cap. The spark can't discharge down the plug wire so it jumps inside the cap. If you haven't already done it then take the cap and wires off and lay them on a table and fit new plugs in the ends and take a resistance reading from the post inside the cap to the plug center electrode and write down all the readings and compare them.

    A question, you don't have the plug wires zip tied together in a bundle?

    Also, what is your compression ratio? Is this a guess or have you measured it?
     
    #22
    Last edited: Sep 20, 2013
    Mike Canter, Sep 20, 2013
  3. Mark Leigh

    Mark Leigh Member

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    Duct tape around plug wires is no good either ---
     
    #23
    Mark Leigh, Sep 20, 2013
  4. Blown5402

    Blown5402 Member

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    Comp ratio is 10.5 to 1

    Mike, Compression ratio is 10.5 to 1 and this is a new engine combo with 7 full 1/8 mile passes on it now. The wires are wire tied together, but separated apart from each other with good spacing. I am checking all wiring today and rewiring to make sure all is good! We are off this weekend due to rain and I have time to check everything before the next race! THANK YOU to all! Jim
     
    #24
    Blown5402, Sep 20, 2013
  5. go green

    go green New Member

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    You could be too rich to light the fuel . David Hance runs MSD Grid and a 7 box .BAE 8 Hemi ,Twin 94mm,11-1 compress,9700 rpm ,50+ psi , 3.6 AFR
    He has been over 240 MPH with his 3200 pound outlaw car . The proper fuel curve doesn't need the big spark but a bad one does .
     
    #25
    go green, Sep 20, 2013
  6. Blown5402

    Blown5402 Member

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    I Maybe found the fault, but not tested yet????????

    We will not run this weekend due to rain, but as I was rewiring today, the ground on the negative/ground side of the coil from both heads had come loose most of the way. My fault; and it was a crimp type connector and I never run crimp connectors (always solder), but got in a hurry, and the wire just pulled out and was loose in the connector. Hopefully like most people have always said, usually it is a ground problem and this cost me 3 weeks of racing and qualifying too! THANKs for all of the help and advice and I will report the results back after we run! THANKS! Jim
     
    #26
    Blown5402, Sep 20, 2013
  7. Blown5402

    Blown5402 Member

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    Fuel Curve

    I have been rich testing the new motor/car combination, but EGTs showed good fuel curve and temps were where I needed to be, and if it was not random cylinders, I would have looked at the same cylinders dropping, but think maybe the ground caused my problems, but THANK YOU for the advice and help to all! Jim
     
    #27
    Blown5402, Sep 20, 2013
  8. overkill69

    overkill69 Member

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    fuel

    screw cars have a bad fuel curve by nature. most people deal with dropped cylinders at launch because of distribution problems. lots of effort went into correcting it and it didn't really go faster so we just tune around it.
    On paper,an efi system with nice AFR in every hole should be a huge gain...turbos should be the superior power adder too...
    I guess nobody told Manzo...lol.
     
    #28
    overkill69, Sep 20, 2013
  9. TADHemiracer

    TADHemiracer Member

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    How Could A Bent Shaft Cause Carbon Tracking On An Insulator?

    Agreed X 2. A bent shaft should not cause tracking on an insulator. Maybe the grease you are using to lubricate on the boot to plug has metal or contaminants or OIL or whatever in it. I quit using the boot lubricant for this exact reason. Some DO like it dry. :cool:
     
    #29
    TADHemiracer, Sep 20, 2013
  10. Blown5402

    Blown5402 Member

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    Answer-----Bad Head Ground

    I promised several people that I would get back after the next race and report on the dropping cylinders and what I found. I had a bad ground wire on the heads and after making sure all the grounds were good, went back to running great and went a many 4.00s and a 3.98. Now, we just need to tune some with all cylinders firing and get to racing more! THANKS! Jim
     
    #30
    Blown5402, Oct 15, 2013
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