Comp tests come back bad a lot of the time? You are the first person I have ever heard that from. You make sure the engine is WARM, as a cold engine will throw the compression off. If you tried two different compression testers, and both came back with low readings on those two same cylinders, the chances of their actually being a problem grows exponentially. You really think you could have two faulty testers with the readings being the exact same?

As SYNRGY said, all rings don't go bad at the same time. It is a little rare to see two on their way out at the same time, however it is far from impossible. The oil in the cylinder sealed it for me, that makes me truly believe it is a ring problem. Either that or a slightly cracked piston, which is a little extreme and probably not the case considering you said it runs fine (no blue or white smoke at idle).

As I said before, boroscope those two cylinders to make sure the piston surfaces look alright and that there isn't any scoring of the cylinder walls as this could be another issue causing low compression.

If you aren't confident in your compression test, take it into a shop, a local one should do it for rather cheap. Then you know 100% that if it verifies your same findings that there is in fact a problem.

The problem with taking it into mitsubishi is that your chances of them covering it under warranty are slim to none. If you have ANY induction parts, or bolt ons to that motor they will claim that that increased the stress on the pistons, thus causing the fault on the rings (if that is the case). On top of that they will probably void the warranty all together, so if you come into a problem down the line that might be covered under the warranty you will then be out of luck.


Cliffs notes:
1) Chances are, its the rings.
2) Boroscope the motor to make sure piston surfaces are in tact, and see if you can see any problem with piston rings. Also look for scoring on the cylinder walls (previous owner or you could be running lean and caused a problem)
3) Take it to shop to verify low compression in those two cylinders
4) After problem is verified either get parts yourself or take it to a shop and have it fixed.

 

well as of right now the weather is really cold... but in spring on the hottest day i will drive around for a while then do the test when its warm cuase i did both these tests in colder weather... the 1st and 2nd tester were actually the same one just a different gauge but the same thread and hose... the 3rd was my buddies he just bought and it was at about 1:00 o,clock in the morning, it was freezing. It just blows my mind, the car has 38k all factory boost, i run 10 lbs around town to be easy on it... if i take it a track or anything i bump it to hold 19 and peak 21... it is tuned but i guess **** happens! oh well, i figured mitsu would not cover even if i took the tune off and mbc and intake and everything, so oh well

 

i also heard if you leave just a tiny bit of ATF in the cylinder and leave it over night it could break the rings away from the piston if there is carbon built up on them so that ring does not spring out around the cylinder walls, is that true.... i did that about 4 months ago and have never checked it after so who knows?

 

I just had mine done, it tested between 177-179 all the way across and the leak down test was perfect also. I was afraid of a blown HG but it looks like it is a MAF causing my temps to act odd and the car to run like sheet!

 

You can have the motor plenty hot enough to do a compression test in the winter time. Drive the car around for 10 minutes, get the coolant/engine temp gauge up to running levels and then start the test, but make sure to not let it cool off. The whole point in needing it warm is simple, cold weather contracts objects (such as the metal pistons, rings, etc.) and warm expands it. A cold engine could show off compressions merely do to the cold ring not properly expanded and seated against the cylinder wall.

I understand you are taking precautions on treating your car well, but the fact of the matter is that you bought it used. You really have no idea what the previous owner did to it, other than either his word of mouth or that of a dealer and they would both lie to you in a heartbeat to make the sale. It would have been worth ten times the money to have done a compression test before the purchase to see if the problem was existing, or something your previous driving habits have done.

Now you will never know.

I would not do a trick such as the ATF fluid. You tried the oil and it proved a point to you (hopefully) that something in there is not completely sealing off the combustion chamber from that of the lower crankshaft chamber. I would take the motor in and have it boroscoped and your compression test results verified. After that you can either rebuild it yourself or take it to a reputable shop. You live in California, there are many viable options.

 

Ok well i could not stand not knowing so this morning i took it to a shop and they ran a leak down and a comp. test and they said that all 4 were about 164 psi and the leak down test came out good and they said nothing was wrong with it... i asked them about a boroscope and they said they felt really good about the tests and they drove it and said it runs like a 10.

They said i might have just been doing it wrong... they said WOT while warm is the best time.

After this thread you have no idea how scared i was when they called me over the phone.... i feel 100% better now... thanks for all the comments otherwise everyday i would have worried about it