Compression Hi, I have a 2006 Chevy Malibu. The engine experienced catastrophic failure. I went to salvage yard and bought 2.2 echo Tec motor from 2005 cobalt. Thus motor ran fine in cobalt. but when I installed it in Malibu it would not run, when I cranked it over it spins very fast. So I ran compression. re: cylinder 1 = 30lbs , cylinder 2 = 5lbs, cylinder 3 = 5lbs, and cylinder 4 = 30lbs. any ideas?

It sounds as thou it sat unattended in the salvage yard (not covered up and in the elements) or sat for an extended period of time and the rings arent seated...get in touch with the salvage yard first, and inform them to the issue showing them compression readings...mix some transmission fluid (just the older normal atf) and a bit of diesel together and pour some down each spark plug hole then let them sit for a day...leave plugs out the next day and crank engine over for about 15 seconds...reinstall plugs and see what happens..if compression remains low, get salvage yard to replace engine with another.

The head on the motor you bought is bad; or the head gasket is leaking; or the rings in the 2 center pistons are bad. 30 lbs is far too low of a compression, and 5 lbs is garbage. They should be closer to 80 or 90 psi and not have more that 5% variance between the cylinders.
The first thing you will have to do is pull the head off and check it. Or you can take it back to the salvage yard you got it from, show them the results from the compression test and either get another motor, or have them refund your money.