compression test results
Evolving Member
Joined: Jul 2006
Posts: 299
Likes: 0
From: Yardley, PA
To do a leak down test.... Depending on where you got the compression tester at, there should be a little adapter/extension thing. (it should have the same size threads as the tester you used before, but have no one-way valves) Take that to home depot/lowes and use plumbing to extend it and end with a quick release for an air compressor. Put the regulator on the compressor to 100 psi. Warm up the car. Take off the cam gear cover to see the timing marks. Disconnect that crank position sensor, and get the #1 cylinder to TDC. Take out all your spark plugs where you have low compression. Screw in your frankensien adapter and put 100 psi into the cylinder. Listen for leaks. If you hear a leak from the exhaust it is the exhaust valve, if you hear it from the intake (you will probably have to take the intercooler pipe closest to the TB off for this) it is the intake valves. If it is the rings you should hear it when you take off the oil cap. If you hear it coming out another spark plug hole it is your head gasket. Repeat with each cylinder that has low compression. Oh yea, make sure the cylinder that you are pressurizing is at TDC.
I think I covered the whole procedure.
I think I covered the whole procedure.
leaky throttle body gaskets are pretty common on the Evo 9's. I think they just got sloppy with the build on the 9 throttle bodies. I've had 9's with 2000 miles in the shop with bad gaskets. Way more than 8's.
If you do the pressure test and you hear the air from throttle body and it changes pitch when you move or press down on the body shaft then it is the seals.
Obviously this has nothing to do with your low cyl compression numbers though.
I usually don't do the 5 missisippi thing though. I just crank until the needle stops jumping up. You also don't need to disconnect any sensors. Just make sure you are WOT when you are doing the cranking, this will shut off the injectors.
Leak down test is actually easier than it sounds. I use a ratchet extension place (carefully!) into the cyl and use a wrench to move that specific cylinder to TDC. Then I perform the leak test. You need an air compressor for this test.
If you do the pressure test and you hear the air from throttle body and it changes pitch when you move or press down on the body shaft then it is the seals.
Obviously this has nothing to do with your low cyl compression numbers though.
I usually don't do the 5 missisippi thing though. I just crank until the needle stops jumping up. You also don't need to disconnect any sensors. Just make sure you are WOT when you are doing the cranking, this will shut off the injectors.
Leak down test is actually easier than it sounds. I use a ratchet extension place (carefully!) into the cyl and use a wrench to move that specific cylinder to TDC. Then I perform the leak test. You need an air compressor for this test.
leaky throttle body gaskets are pretty common on the Evo 9's. I think they just got sloppy with the build on the 9 throttle bodies. I've had 9's with 2000 miles in the shop with bad gaskets. Way more than 8's.
If you do the pressure test and you hear the air from throttle body and it changes pitch when you move or press down on the body shaft then it is the seals.
Obviously this has nothing to do with your low cyl compression numbers though.
I usually don't do the 5 missisippi thing though. I just crank until the needle stops jumping up. You also don't need to disconnect any sensors. Just make sure you are WOT when you are doing the cranking, this will shut off the injectors.
Leak down test is actually easier than it sounds. I use a ratchet extension place (carefully!) into the cyl and use a wrench to move that specific cylinder to TDC. Then I perform the leak test. You need an air compressor for this test.
If you do the pressure test and you hear the air from throttle body and it changes pitch when you move or press down on the body shaft then it is the seals.
Obviously this has nothing to do with your low cyl compression numbers though.
I usually don't do the 5 missisippi thing though. I just crank until the needle stops jumping up. You also don't need to disconnect any sensors. Just make sure you are WOT when you are doing the cranking, this will shut off the injectors.
Leak down test is actually easier than it sounds. I use a ratchet extension place (carefully!) into the cyl and use a wrench to move that specific cylinder to TDC. Then I perform the leak test. You need an air compressor for this test.
haha
so we will see.
as far as the leak down test, i have a compressor but im still not sure of exactly what u do here. i will leave that to the pros until i know what im doing. im not going to F up someones car u know. but i def apreciate all the responces.
that lil bastard wont post here for some reason. i told him too.
Paul get us *** on here and post something!
holy **** guys read this email i just got from the kid whos car this is
"ok the dealership told me this:
that they did not do a compression check because it was a customer request and if i wanted one done it was 350 dollars. also they told me that did a engine check and everything checked out fine including the boost being where it should and i asked the guy bout the gage and he said thats it measures boost to air ratio and is not actually a boost gage (so then what the **** is the point of the thing i have).
what do u think"
boost to air ratio ? wtf?
i told him they were feeding him BS
"ok the dealership told me this:
that they did not do a compression check because it was a customer request and if i wanted one done it was 350 dollars. also they told me that did a engine check and everything checked out fine including the boost being where it should and i asked the guy bout the gage and he said thats it measures boost to air ratio and is not actually a boost gage (so then what the **** is the point of the thing i have).
what do u think"
boost to air ratio ? wtf?
i told him they were feeding him BS
Last edited by deadbeatrec; Jun 3, 2008 at 12:25 PM.
what i am going to do is, i have an extra boost gage around so i will hook that one up and read what that one says.
as far as i know the stock gage is mechanical correct? wtf? y does mitsubishi have to be so gay about this
as far as i know the stock gage is mechanical correct? wtf? y does mitsubishi have to be so gay about this
holy **** guys read this email i just got from the kid whos car this is
"ok the dealership told me this:
that they did not do a compression check because it was a customer request and if i wanted one done it was 350 dollars. also they told me that did a engine check and everything checked out fine including the boost being where it should and i asked the guy bout the gage and he said thats it measures boost to air ratio and is not actually a boost gage (so then what the **** is the point of the thing i have).
what do u think"
boost to air ratio ? wtf?
i told him they were feeding him BS
"ok the dealership told me this:
that they did not do a compression check because it was a customer request and if i wanted one done it was 350 dollars. also they told me that did a engine check and everything checked out fine including the boost being where it should and i asked the guy bout the gage and he said thats it measures boost to air ratio and is not actually a boost gage (so then what the **** is the point of the thing i have).
what do u think"
boost to air ratio ? wtf?
i told him they were feeding him BS
and $350 for a test? what do they charge $65 a min?
Until they make valves and pistons with sensors in them, doing a scan isnt going to do anything.
Either there really retarted or just didnt want to work on the car. that simple.
lmao i just thought of what the dealer said about the boost gauge....it reads in BAR units not psi,
So i guess he thinks it stands for Boost to Air Ratio
1 bar to us is 14.5psi, what it means to
dealer i have no idea.
So i guess he thinks it stands for Boost to Air Ratio
1 bar to us is 14.5psi, what it means to
dealer i have no idea.
