Hello everyone fairly new to s2ki and wanted to try a compression test on my s2000 with 166k miles since I feel loss of power.so I bought a compression test n as I crank all four cylinders read 240 after the 8th crank but as soon as I stop cranking the pressure drops down slowly without my pressing the realease air valve.does that mean theres something wrong with my engine or my new gauge came messed up.hope u guys understood me just stressed out.thanks n would appreciate any feedback.

 

I may be wrong, but I think there might be an issue with your new gauge. Something with the check valve.

 

To have correct reading you need to remove ecu fuse you dont want fuel when doing the test
trottle fully open
And crank 4 time not 8
The check valve may be faulty
Do a leak down test

 

My guess is along with what Fish said.... most likely your Schrader valve is either A. not in or B. not closing properly. It COULD also be that the O-ring inside the quick connect that the gauge plugs into broke or got pushed out of place. (this happened to the first compression tester I had bought which I just took back for a new one)

 

Yeah I also think it might be the actual gauge itself cus its weird how after im done cranking I lose pressure .its those damn harbor freight tools! Lol im gonna stop by sears today n give u guys an update.thanks you guys for your input tho

 

Pull the fuel pump fuse. Not sure why the ECU fuse.
Make sure you engine is warm for correct results!
Also, if you're just checking out of curiosity and there's nothing too out of place, a leak down test is always great but it's a little overkill.

 

Why would a leakdown test be a little over kill.i just figure to do a compression test since my car has so many miles.n idk if I want to invest money on it or just buy another swap with less miles.

 

Because there is nothing specifically wrong, like I said earlier. That's just my opinion, do a leak down test for all I care, it'll definitely give you better answers than a compression test.

 

Well guys thanks alot for your inputs.turns out that my compression tester gauge was bad.damn you harborfreight!! I went to sears and got me a good one.my reading were 220,225,225,225.starting from cylider one.would u guys say its pretty good for having 166kmiles?

 

I think that's excellent!