Compression Test post cylinder crack (2018 CX-5 NA)

[nolig36]

Ok So back in January I had the head replaced due to the crack. Today I decided to do compression test. The first try with cylinder 1 I got 152 then i did the others 142, 140, 130. I went back and redid them again and #1 went to 135. Is this cause of some variable timing of the valves? End result of 135, 142, 137, 130 would be within spec but that 152 would have put it borderline problem being 22psi above the lowest cylinder.

2018 2.5 NA

 

[edmaz]

Did you relieve fuel pressure before starting the test?

 

[nolig36]

I only pulled the fuel pump fuse and coil fuse. I guess that would explain it Thank you!

 

[edmaz]

Yes, very likely was caused by the high pressure pump using up what was left in the line, and then nothing was left after the engine turned a few times for cyl #1. You could probably confirm that by running another test the same way, although you probably have better thing things to do than that