Leak down test question

[YZFR1]

Hi,

i was doing a leak down test on my fresh engine. For the most part everything seemed fine, the readings i got were all between 10-13% which is not bad for a new engine.

However, the very first time i tried testing cylinder #3, i got air escaping out of cylinder #4. Tried to do the same a few more times and could not repeat the same result and other than that the cylinder gave me roughly the same readings as others.

My question is, are there any conditions other than a blown headgasket that can make air escape out of an adjacent cylinder?? And if it did it once, how come i couldn't repeat it?

The only other way i see it possible is through an intake manifold since all cyliders share the same plenum.

Some feedback on this issue would be much appreciated!

Thank you

 

[boost97gst]

Im not sure but your hypotheseis makes sense. If the intake valves of the cyl being tested and the adjacent cylinder were slightly open then you could expect a slow leak form one to another through the plenum/IM.