I just did a compression test with a piston tester. I held the check valve open like youre supposed to. I saw even pulses of 90-95 psi on all 6 faces. however both times when I let go of the check valve I saw 125 psi. how is it possible to see 125 psi if all 3 faces are putting out 90-95? is it that the bounces are just too fast to register fully on a piston tester and thats why I only see 90 - 95?

Thanks.

 

Thats called the accumulative pressure. 125 psi is good according to the Bruce Turrentine 13b rebuild video. Your all good.

 

so then it must be something else? Im thinking it is a short somewhere or a bad CAS, TPS, or MAP sensor. my voltages are good for the TPS and my map sensor shows -39mmHG when off, but it has always done that. I dont know how to check the CAS. Could it be spark plugs? they only have ~300 miles on them. I changed them before I went to the tail of the dragon this weekend.

 

What kind of problems are you having with your car? You first asked a question about compression testing, now your throwing in questions about the TPS and CAS.