blown piston ring?

[curtis265]

comp test takes a few 5 minutes so it shouldn't be costly. You remove the spark plug and unplug the injectors then screw in a compression gauge and crank the engine to see how much air pressure it can withstand. Then tell us how much each cylinder held here and someone will be able to tell you if you're ok or not.

[hmetro24]

jump to supercheapauto get compression test tools( got mine for 30$), 16mm deep socket + extension + ratchet.
take spark leads, Note: Do not take the spark lead from the distributor, you may forget how to put the back
take spark plugs out. easy way to take the spark out: Unscrew the spark plugs until it come loose, put the spark lead on the spark hole until it clip to the spark plug and take it out.
screw the compression tools in.
crank the engine for couple of seconds, write down the psi,
repeat the test for each cylinder.

you can try wet compression after you do dry compression. put a lil bit of oil inside the cylinder throw the plug hole and repeat the test again and write down the psi for each cylinder.
Wet test will tell that pistons rings are bad or good depends on the psi you are getting.
when ever you finish the test put everything back, start the car. it will blow smoke, do not panic it the oil you put on the cylinders it will take some time to burn all the oil.

for example:
dry test. cyl1 : 180 psi cyl2 : 180 psi cyl3 : 180 psi cyl4 : 180 psi +- 5-10
this mean the head is allright
wet test cyl1 : 240 psi cyl2 : 240 psi cyl3 : 180 psi cyl4 : 180 psi +- 5-10

this will mean that compression is good but piston rings in cylinder 1 and 2 are bad because the pressure jumped up.
dry test: cyl1 180 psi cyl2 : 130 psi cyl3 : 125 psi cyl4 : 180 psi +- 5-10
if you get like that, this mean some thing is wrong in cly 2 and 3, could be valves seat, bent valves, wrapped head, headgasket.

how to do compression test
how to do leak down test

[aaronng]

Pull the fuse for the ignition circuit before you run the compression test. If you have the system trying to generate a spark without the sparkplugs in, you can damage your ignition coil.

[Bludger]

Pull the fuse for the ignition circuit before you run the compression test. If you have the system trying to generate a spark without the sparkplugs in, you can damage your ignition coil.

not many people think of this,.

[curtis265]

Pull the fuse for the ignition circuit before you run the compression test. If you have the system trying to generate a spark without the sparkplugs in, you can damage your ignition coil.

ohshit good idea lol