I recently did a compression test on my MY00 S2000. The compression tester was off already. Instead of reading 0 psi when it wasn't in use, it said 40 psi. So, I did the compression test and it read 195-200 all the way across. So, I assume I would take the 40 psi I had before the test and minus it from the 200, which would be 160 across. Any ideas what might make the car have low compression all the way across? My first assumption was rings, but all four diminishing equally seemed a bit peculiar.

 

Are you serious? You need to start with a properly calibrated compression guage. Do that and then get back with us.

 

First thing is find another gauge set and re-test. If it is starting at 40 you can't just assume it is reading high when you are performing the test. You could get yourself wrapped into trying to fix a problem that doesn't exist.

 

Guys, I know what your saying is obvious, but I just thought I'd get a couple ideas as to why I may potentially have low compression? Are there other reasons besides the rings? Especially considering that they're all nearly the same.

 

I agree with getting a different gauge and then testing. You will never know how acurate that guage is if its reading like that. But usually if all of the numbers are the same across the board you dont have much to worry about.

 

That's what I wanted to hear. I'll go get a gauge in the next few days and I'll update this thread. Thanks again!


EDIT: One other thing, what should the compression be on an AP1 with no internal work done?

 

They say 240, but most tests come out around 220 or around that range. Here is a link to the DIY compression test. Make sure you follow every step b/c it could cause flaws in your test. In the end of his post it says reading the results. Hope this helps and good luck!
https://www.s2ki.com/forums/index.php?showt...0&#entry8957870

 

^ I appreciate it! Thanks!

 

i thought as long as the numbers are consistent, then it's fine?

 

Not true. You should verify the gauge and process are OK but all consistent means is the cylinders are all close to each other. That could mean all your intake valves are bent similarly or your exhaust valves are all burnt similarly. It may not necessarily be a good thing.