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compression test?

Old 05-08-2012, 01:36 PM
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hey guys im gonna do a compresion test tomorrow to see which cylinder is misfiring..i just wanna make sure i got it right
i pull out my fuel pump fuse so no fuel gets to the motor
then i remove the plug, stick the tester in there and turn the motor over
which ever cylinder/cylinders have low compression, should be the bad one correct..
anything im missing? thanks!!
Old 05-08-2012, 06:19 PM
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I don't think you just turn it over. I think you need to get the cylinder thats being tested positioned at Top-Dead-Center.

Maybe I'm thinking leakdown test.....

.
Old 05-08-2012, 06:22 PM
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remove all the plugs... insert compression tester... crank till it stops moving the needle in the gauge... write down the number and proceed to do all 8...


all the holes should be withing 10-15% of one another... id hope for better personally tho
Old 05-08-2012, 07:16 PM
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oh so i do remove all? i thought just one at a time
Old 05-08-2012, 07:17 PM
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if you have a blown head gasket between cylinders leaving the plugs in will push the compression into the other cylinder and build more compression than it truely has
Old 05-08-2012, 10:40 PM
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oh that makes sense, i doubt it is the gasket, there new..im thinkin its blow by, but thanks for the tip!
Old 05-09-2012, 08:20 AM
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Originally Posted by z28oc91
oh that makes sense, i doubt it is the gasket, there new..im thinkin its blow by, but thanks for the tip!
not a problem man... only way i learned was when my boss yelled at me sooo... lol


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