i blew my motor a couple weeks back and i was at my friends garage, he is a mechanic from honda, and we were going through the list of possible things that are wrong so we ran a leak down and compression test. everything was going good except onthe leak down test, we found that cylinders 1 and 2 ( going left to right) were giving us a reading of positive psi, ex. we were pumping in 75 psi of air and were getting a reading of 81 back. Anyone ever experience this?

We found that cylinder 3 has the blown piston rings, and we ran a compression test with cylinders 1,2,and 4 at 180 and cylinder 3 at 170. So it wasnt anything with the equipment but it has both of us stumped. any input would be awesome

 

Your tester is broken or the guages are not calibrated to each other. Cylinders 2 and 3 being a little lower on a compression tester isn't unusual, I wouldn't even worry about one of them being 10 PSI off. What were the leakdown numbers for the other two cylinders?

 

if i remember correctly cylinders three and four were showing about a 9% loss of pressure. so we dont think it is the equipment because those two cylinders showed a decrease in pressure, so we were pumping in 75 psi and those cylinders were holding only about 68 psi of air, so that is where the problem comes in. those cylinders were reading fine, but 1 and 2 were off.

 

it is the gauge, there is nothing nothing nothing that would ever allow that to happen.

 

thats what i figured. it was just weird that it would read fine on the third and forth but not the first and second.

 

BTW, I believe the cylinders go 4,3,2,1 from left to right

Pretty sure.

 

Unless the guage is way off and there is actually a lot more leakdown on 3&4, but the tester only shows a little while 1&2 are not leaking down much so it shows a pressure increase. My tester has a coupler that seals if I detach the line to the cylinder so I see full pressure on both guages. That lets me see how far off the guages are. I have a cheap-*** Summit tester though, with a Craftsman coupler from my compression guage connected to it because the Summit one broke almost immediately, and I have to tap the guages a bit to make sure it isn't sticking. A friend of mine has a really nice Mac tester, and he gets the guages calibrated annually to make sure it's accurate. He does this stuff for a living though, I just do it as a hobby.