View Full Version : compression test?


z28oc91
05-08-2012, 02:36 PM
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!!

LS6427
05-08-2012, 07:19 PM
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.....

.

SVTconfused
05-08-2012, 07:22 PM
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

z28oc91
05-08-2012, 08:16 PM
oh so i do remove all? i thought just one at a time

SVTconfused
05-08-2012, 08:17 PM
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

z28oc91
05-08-2012, 11:40 PM
oh that makes sense, i doubt it is the gasket, there new..im thinkin its blow by, but thanks for the tip!

SVTconfused
05-09-2012, 09:20 AM
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