a few weeks ago i did a compression test on my 03 ap1 w/ 134000 miles. the numbers were 215-225 all 4 cylinders. I did a compression test day again and this numbers came out to be 170-180 all 4 cylinders. I'm confused could it be that I used a different compression tester?

 

Different compression testers can show different numbers. Was the car warmed up both times? Hold the gas pedal all the way down? Battery have enough juice to crank enough for the numbers to hit the max they would go?

 

I like to have somebody else crank so that way I can look at the gauge and you can see how it builds after 1 crank,2,etc.

 

^That's what I do too. Had lower than normal numbers since my battery was not doing so hot. Got a new battery and cranked the numbers up to great compression results.

 

yea i had my buddy holding the compression tester. also i used jumper cables, and yes i was holding the gas pedal and took out the fuel pump fuse.

 

Was it on a hot/warm engine?

Even with jumper cables attached to my civic my car wasn't making enough cranking power to get higher numbers. Had to let it sit for a long time. So my battery was going out but if you have a weak battery could be that as well but would most likely give inconsistent numbers.

Most likely just different numbers due to a different compression tester.

 

ya i had three bars on the coolant temp.

 

what led you to do another test?

If the car is driving fine, I wouldnt worry. Remember your looking for difference not absolute numbers.

 

I went into a wrong gear couple times and it bounced off the rev limiter. I just wanted to make sure I didnt mess up anything.

 

A visual inspection might tell you more...