Originally posted by B20BbenN
Always open the butterfly when you do a compression test!(bypass the + on the starter , not turn the key...)
If you open the butterfly during the compression will be higher!
i've heard you're supposed to have the throttle at wot, but i still don't get why. lets say the intake valve isn't seated properly and is having a low compression because or that. won't having the throttle closed help the compression because the throttle plate is allowing the air to stay in the cylinder/engine? just curious here...
but anywayz.. any of what they say can be a cause of low compression but there are more possibilities... are you burning any oil? are you loosing coolant? was a leak down test done after the compression test?