Compression Testing.
05-25-2006, 11:47 PM
#1
5th Gear Member
Thread Starter
Join Date: Jul 2004
Location: Pittsburgh/Dayton
Posts: 3,062
Compression Testing.
Well its getting to the point where I'm going to have the money to supercharge it within the next month. I've been putting this off forever... contemplating whether or not to do it. Pretty much if my engine blows im screwed... I was thinking of getting a p1sc in the neighborhood of 350-360rwhp.
My car has 81k on it.... kinda high. So I figure if i do a compression test and all is well, the mileage isnt really that big of a concern that its not going to blow up on the dyno haha.
So has anyone done this, seen a tutorial (link) etc? Anything would be useful; I know you can buy the thing from autozone to do it... however i'm not sure whats good bad and so forth.
My car has 81k on it.... kinda high. So I figure if i do a compression test and all is well, the mileage isnt really that big of a concern that its not going to blow up on the dyno haha.
So has anyone done this, seen a tutorial (link) etc? Anything would be useful; I know you can buy the thing from autozone to do it... however i'm not sure whats good bad and so forth.
05-26-2006, 02:39 AM
#4
3rd Gear Member
Join Date: Jun 2005
Location: Illinois (Tinley Park)
Posts: 760
RE: Compression Testing.
Well I've done compression tests on some of my old cars but not in the last 20 years or so LOL. All I used to do is screw the gauge into the spark plug hole and pull the coil wire then turn the motor over, but I'm not sure how to do it on our cars with the coil on plug.
05-26-2006, 02:43 AM
#5
6th Gear Member
Join Date: Sep 2005
Location:
Posts: 5,128
RE: Compression Testing.
okay now first make sure you have a good battery, as you will be cranking quite a few times.
First, disable fuel (pull fuel pump relay) and let run until it dies (or crank over a bit). Now you can crank w/o it firing.
Next, go to autozone and get one of those "actron" compression gauges. I have one, it works great. Around $40.
Make a neat piece of paper with sections for each cylinder so you know which goes to where.
Remove spark plug of applicable cylinder
For each cylinder to be tested, screw the compression gauge into the spark plug threads. Get into car, hold throttle at WOT and crank over 3-5 revolutions. (set the gauge so you can somewhat see it from inside) and wait until you see the gauge jump 3-5 times.
Record the reading that is there after you crank. Then push the pressure release button.
I reccomend that you do this twice per cylinder.
Repeat this for every cylinder and record your readings.
You want the lowest reading to be no less than 80% of the highest reading. On my engine they were all around 150psi, w/ 112k on the clock.
I hope this helps, and let me know what you find
First, disable fuel (pull fuel pump relay) and let run until it dies (or crank over a bit). Now you can crank w/o it firing.
Next, go to autozone and get one of those "actron" compression gauges. I have one, it works great. Around $40.
Make a neat piece of paper with sections for each cylinder so you know which goes to where.
Remove spark plug of applicable cylinder
For each cylinder to be tested, screw the compression gauge into the spark plug threads. Get into car, hold throttle at WOT and crank over 3-5 revolutions. (set the gauge so you can somewhat see it from inside) and wait until you see the gauge jump 3-5 times.
Record the reading that is there after you crank. Then push the pressure release button.
I reccomend that you do this twice per cylinder.
Repeat this for every cylinder and record your readings.
You want the lowest reading to be no less than 80% of the highest reading. On my engine they were all around 150psi, w/ 112k on the clock.
I hope this helps, and let me know what you find
05-26-2006, 03:28 AM
#6
3rd Gear Member
Join Date: Jun 2005
Location: Illinois (Tinley Park)
Posts: 760
RE: Compression Testing.
ORIGINAL: monkeydude3
okay now first make sure you have a good battery, as you will be cranking quite a few times.
First, disable fuel (pull fuel pump relay) and let run until it dies (or crank over a bit). Now you can crank w/o it firing.
Next, go to autozone and get one of those "actron" compression gauges. I have one, it works great. Around $40.
Make a neat piece of paper with sections for each cylinder so you know which goes to where.
Remove spark plug of applicable cylinder
For each cylinder to be tested, screw the compression gauge into the spark plug threads. Get into car, hold throttle at WOT and crank over 3-5 revolutions. (set the gauge so you can somewhat see it from inside) and wait until you see the gauge jump 3-5 times.
Record the reading that is there after you crank. Then push the pressure release button.
I reccomend that you do this twice per cylinder.
Repeat this for every cylinder and record your readings.
You want the lowest reading to be no less than 80% of the highest reading. On my engine they were all around 150psi, w/ 112k on the clock.
I hope this helps, and let me know what you find
okay now first make sure you have a good battery, as you will be cranking quite a few times.
First, disable fuel (pull fuel pump relay) and let run until it dies (or crank over a bit). Now you can crank w/o it firing.
Next, go to autozone and get one of those "actron" compression gauges. I have one, it works great. Around $40.
Make a neat piece of paper with sections for each cylinder so you know which goes to where.
Remove spark plug of applicable cylinder
For each cylinder to be tested, screw the compression gauge into the spark plug threads. Get into car, hold throttle at WOT and crank over 3-5 revolutions. (set the gauge so you can somewhat see it from inside) and wait until you see the gauge jump 3-5 times.
Record the reading that is there after you crank. Then push the pressure release button.
I reccomend that you do this twice per cylinder.
Repeat this for every cylinder and record your readings.
You want the lowest reading to be no less than 80% of the highest reading. On my engine they were all around 150psi, w/ 112k on the clock.
I hope this helps, and let me know what you find
i've had to do this more than a few times on various vehicles
05-26-2006, 01:11 PM
#9
6th Gear Member
Join Date: Sep 2005
Location:
Posts: 5,128
RE: Compression Testing.
let me know what you find, and from your mods it seems like the car hasn't taken any rediculous beatings except normal romping, which with normal maintenance is nothing. so u should be fine
05-27-2006, 08:05 AM
#10
2nd Gear Member
Join Date: Apr 2006
Location:
Posts: 417
RE: Compression Testing.
You can shut off the fuel by tripping the impact switch in the trunk just behind the rear carpet panel. Just smack the bracket with a rubber mallet and the red reset button will pop up. Next, unplug the crank sensor at the front of the motor, kills the spark. Remove ALL of the plugs, leaving a few in will slow it down, then block the throttle body wide open. This should be done with the motor warmed up as this will give more accurate readings, good luck.