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???Compression test?? What does this mean?

Discussion in 'Engine Building' started by rawerz, Nov 17, 2006.

  1. rawerz

    rawerz New Member

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    I have a 1991 CRX Si with a stock D16a6 Motor in it. The guy said that he thought the timing belt was broken by the previous owner, he never tried to fix anything. I got a new compression tester today, I have never used one. I went cylinder to cylinder pulling the spark plugs and testing them. I only got a jump between 30 psi to 60 psi never any more or less. Im thinking this has to be caused from the valves being bent since he did say the timing belt had been broken. Note: the timing belt wasnt broke but the guy might have replaced it.

    Please tell me what this means and how to fix it?

    thank you.
     
  2. phunky.buddha

    phunky.buddha Admin with a big stick Admin VIP

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    If the valves are bent for sure, pull the head and start evaluating your damage.

    For a compression test, unplug the distributor, pull the fuse for the fuel pump, then plug in the gauge at the spark plug hole for the cylinder you want to check. Get in the car, and hold the gas pedal to the floor. Crank the engine until the gauge stops going up- about 3-4 pumps usually. Read the value on the gauge.
     
  3. Turbo&Auto

    Turbo&Auto Nick Go FAST!!

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    I've never heard that part about holding it WOT before, what does that do for you? I still got about 200psi just inserting the tester in a plug holes and cranking it 3-4times.
     
  4. igotnothin

    igotnothin New Member

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    did you warm the car up. the numbers are still low for a cold test,b ut who knows might not be as ow as you think. if i were you id buy a new head for 200 or so and call it a day. lol
     
  5. phunky.buddha

    phunky.buddha Admin with a big stick Admin VIP

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    200psi is good, not low. You want to have even numbers across the board, or at least within 5% of each other from lowest to highest.

    Holding the throttle down makes sure that you get the best flow of air into the cylinders- otherwise you're just trying to squeak air around a closed throttle plate.
     
  6. rawerz

    rawerz New Member

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    I think a ew head will work. The vehicle doeasnt run because of the low psi the cylinders arre holding. So a new head will be my best bet?
     
  7. igotnothin

    igotnothin New Member

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    yea vasue you can pick up D series heads farily cheap used in good working order. sometimes its easyer than taking yours apart and fixing it. sell yours for parts or keep it incase you miss a shift from 3 to 4 and hit 2 ops
     
  8. rawerz

    rawerz New Member

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    Thanks guys I appreciate it. :D
     
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