The gauge on my old compression tester decided it had served well enough after several years of non-use, it's demise helped along by a good dose of rust. I needed one for a project car I just started working on so I went ebay shopping for a replacement gauge to go on my hose & adapters.

I found a Proto CTR-20 gauge on ebay, USA made, brand new according to seller, with a release valve for a good price of $15 including shipping but there isn't a check valve to hold the pressure for cumulative readings. On my old gauge, it must be built into the gauge's body as I don't see any kind of external check valve on it.

When cranking the engine, the needle jumps up to max and back to zero for each cycle. I'm not familiar with how a standard automotive compression tester is supposed to work here, other than it should hold the pressure and increase the reading a bit with each crank cycle of the motor.

Can anyone enlighten me on how to get this working the way I remember it should?

Here's the gauge screwed onto my hose:
http://www.token.crwoodturner.com/im...iongauge01.jpg
http://www.token.crwoodturner.com/im...iongauge02.jpg