? bout compression testin my engine?

Question

i have a 91 corvette that is supposed 2 b runnin on 165 pounds of compression, when i test it at an idle i have bout 90 pounds when i test it with a wide open throttle i have 165-180 pounds.... am i supposed 2 b testin it at an idle or wide open, and is my compression good?

Answer 1

you don't do it with it running ,you do it while the engine is off,you need to re-test it,you,ll get different readings on it then,never test one running,good luck.

Answer 2

neither you just crank it over a few times dont have to start the motor to test it 90 is good anything below 50 is bad anything lower needs work.. motor just has to turn over to get a reading

Answer 3

Pull all of the spark plugs and check each cylinder one-at-a-time.  the same number of revolutions for each cylinder (ie 4-5 rotations) not with the engine running.

Answer 4

never test compression with a running engine and always make sure that you only have 1 full stroke to have accurate readings on every piston, multiple stroke can give false higher reading.

Answer 5

you disable the ignition and dont start the car. just crank it for 5 seconds and get the readings

Answer 6

yes you are supposed to test it w/ the engine off, the throttle wide open and most importantly, with a fully charged battery. also there shouldn't be more than a 15% difference between any two cylinders.

Answer 7

idle, not running