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Thread: Valve rattle?Detnation?Spark blowout?Bad gas?

  1. #1
    Junior SCH Member
    Join Date
    Mar 2005
    Location
    Holden,LA
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    8

    Valve rattle?Detnation?Spark blowout?Bad gas?

    I got a problem. When my car gets in the higher rpms, I hear what sounds like valve rattle or something. The valve rattle noise wasn't there when my car was n/a a month ago and started when I added the blower. I thought it was spark blowout so I installed a HI-6 and LX92 coil today. I had a HI-6S and PS91 at first. I thought this would fix it but its still doing it. I'm running 93 octane gas, Autolite 3923's gapped at .030, HI-6 ignition box and LX92 coil, 11 degrees timing and the chip is controlling the rest, SCT tune which I'm not fully satisfied about. Anyone else had this problem or any advice on pin pointing the problem. My tuner is in New Orleans so it may be a while before I can back to him.
    Thanks
    91 LX Coupe 5.0, Built on 5/30/91, 1 of 91
    Light crystal blue met/black Int.
    AFR/FTI/Vortech S Trim Combo

    Pics of my coupe

  2. #2
    Senior SCH Member MikeyMustang's Avatar
    Join Date
    Nov 2002
    Location
    Pittsburgh
    Posts
    276
    Try adding some race gas like unleaded 104 and see if the "rattle" goes away....if so you might want to back down the timming some more or get it retunned

    Mike
    NEW BEST 9.66 @141.02 best mph 141.73 mph!
    AEM tuned by ME!

    http://www.mikeymustang.com

  3. #3
    Junior SCH Member
    Join Date
    Mar 2005
    Location
    Holden,LA
    Posts
    8
    Thanks Mike for the reply. I'll give it a try if I can find some.
    91 LX Coupe 5.0, Built on 5/30/91, 1 of 91
    Light crystal blue met/black Int.
    AFR/FTI/Vortech S Trim Combo

    Pics of my coupe

  4. #4
    SCH Moderator "SN Guru" speedytang's Avatar
    Join Date
    Dec 2002
    Location
    Marengo, Ohio
    Posts
    2,028
    Detonation for sure. Now the question is what was the total timing at wot with boost using the chip. Chips are really not the best setup with boost because it has no boost reference. I would remove the chip if you using bigger injectors or a fmu and set the timing at 19 degrees with the timing jumper on the distributor removed and give it a try.

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