Low Compression?, What am I doing wrong? Options

[silentsprintero]

So i take my car into my auto mechanics class today to do a compression test. Remove all 4 spark plugs (which look perfect) and the fuse for the fuel. Keep in mind the gauge we have is old and that is what I think is the problem, but it read 85psi on the spot across the board. How important is it to have the car warm, i only drove it across the parking lot. also, i notice that my dipstick pops up about 1/2" almost every time i open my hood, what's causing that? i know my compression is higher than that, it pulls strong, so what am i doing wrong?

-Chris

[turbohcar]

The dipstick popping out is a common problem, especially with higher mileage motors. It means you've got some blowby in the crankcase. I usually just grab some pliers and pinch the dipstick tube a bit at the top (while the dipstick is all the way down) and that keeps it from popping out again.

I believe that you have to get the engine to near operating temp to get an exact compression test. Not sure though, I forget. Rob help me out on this one.