Is it possible to have a motor still running with the compression of 15?? My car idles like crap, and wont stay running unless its warmed up, and it smokes when i shift at high rpms, so i decided to test the compression, i removed the two top spark plugs and dissconnected the crank angle sensor, and then held the throttle body wide open and cranked it and the compression was only 15 in the front rotor and then just a little less in the second rotor. Does this mean my motor is shot and needs a rebuild, or did i do it wrong, b/c my car still pulls pretty good. Well i need some opinions or some advidce. Its a 87 n/a.

 

What units are you using? I hope its not PSI

 

The thing would never crank up reliably (even with a flood switch) with compression under 60. Your gauge or your test method is off somehow, though it sounds like you did it properly.

I have seen engines still running with overall compression in the 70's and even 60's, but it was HELL to get them restarted once you shut them off, to the point they weren't really driveable anymore.

Startup is always where low compression exhibits itself most...