92 S10 Blazer TBI Rich

Discussion in 'Domestics' started by Gunnsmith57, Aug 27, 2017.

  1. billr

    billr wrench Staff Member

    Joined:
    Mar 12, 2007
    Messages:
    5,803
    Likes Received:
    57
    Well, I'm really confused now. The spark plug threads/gasket were leaking that bad? That seems impossible. Likewise, the compression gauge should have its own gasket or O-ring there, not dependent on the plug gasket at all. If the gauge worked in the other cylinders, it should have worked OK in #5.
     
  2. Mobile Dan

    Mobile Dan wrench

    Joined:
    Mar 1, 2002
    Messages:
    3,186
    Likes Received:
    33
    Gender:
    Male
    Location:
    Kentucky
    I'm wondering if a "foreign object" was preventing valve closure on cyl 5. Perhaps it finally broke up and valve is sealing again. I would not tear engine apart unless the cylinder "died again". Was the manifold bolt problem on the cyl 5 head?
     
  3. Gunnsmith57

    Gunnsmith57 Newbie

    Joined:
    Aug 27, 2017
    Messages:
    10
    Likes Received:
    0
    Gender:
    Male
    I was thinking the same thing Bill, but the gauge doesn't have any kind of seal at all. I even tried Teflon when I was testing it.

    Dan may be right about something keeping the exhaust valve from closing all the way, but it was driven a couple weeks like that before I ever did anything so I don't know. I figure if it was something, it would have came out before now.

    And the bolt on the manifold was on the other side, so it wouldn't have anything to do with that cylinder.

    I'm inclined to not touch it while it's running better, but at the same time, this weekend is a perfect time to do that gasket again if I had to. I'm thinking this afternoon I'll check compression again on that bank and see what the difference is from the other bank. If there's still a 20psi difference, or if I can still hear the compression hissing out, I'll go ahead and change it.
     
    Last edited: Sep 2, 2017
  4. Mobile Dan

    Mobile Dan wrench

    Joined:
    Mar 1, 2002
    Messages:
    3,186
    Likes Received:
    33
    Gender:
    Male
    Location:
    Kentucky
    My question about manifold bolt location was in regards to "The list of reasons why Gunn should pull that head off again".
     

Share This Page