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correct way to do compression test

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    correct way to do compression test

    I have an old compression tester from back the early '80s. We used to just pull the coil wire & crank the engine to test each cylinder.

    What is the correct procedure to measure the compression on an S50?
    "If the sky were to fall tomorrow, the tall would die first."

    -Dr. Paul Forrester



    Do I LOOK like I need a psychological evaluation???

    #2
    Originally posted by funcrew View Post
    I have an old compression tester from back the early '80s. We used to just pull the coil wire & crank the engine to test each cylinder.

    What is the correct procedure to measure the compression on an S50?
    unhook the DME
    1989 cirrisblau-metallic 325i

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      #3
      Originally posted by SpecM View Post
      unhook the DME
      OK, good; no fuel spewing out the spark plug holes.

      What I mean is, will the comp numbers be legitimate if taken cranking the starter motor? Or turning the crank with a socket wrench? I'm trying to figure out how bad my HG is blown.
      "If the sky were to fall tomorrow, the tall would die first."

      -Dr. Paul Forrester



      Do I LOOK like I need a psychological evaluation???

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        #4
        Use the starter youll never get to turn over fast enough to build pressure by hand.

        Edit: One rotaion of the engine usualy isnt enough crank it for two or three.:D
        Last edited by 416stroker; 09-13-2008, 03:17 PM.
        84 318I Delphin RIP
        87 325IS delphin 24v Sold
        89 325 Alpineweiss

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          #5
          absolute numbers are basically irrelevant, shat is important is that the numbers vary by less than 10% across all cylinders.

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            #6
            Make sure you hook up a jump pack or battery charger so you get the same consistency also.
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              #7
              Originally posted by funcrew View Post
              how bad my HG is blown.

              how bad? kinda doesn't matter, you have to take it apart anyway...
              1989 cirrisblau-metallic 325i

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                #8
                Originally posted by SpecM View Post
                how bad? kinda doesn't matter, you have to take it apart anyway...
                ...Gives me one more thing to procrastinate with. The HG problem is totally creeping me out, and I'm trying to stay in deep, deep denial for a little while longer 'till I can man up and do something about it.
                "If the sky were to fall tomorrow, the tall would die first."

                -Dr. Paul Forrester



                Do I LOOK like I need a psychological evaluation???

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