cranking wave form

dear tech.


is attach wave form look normal and timing is corect

thanks

Spark timing looks good. But there's something inconsistent in the second picture. If it's a V6, that might suggest a problem with one bank or the other.

yes it is v6 xterra 2008
it was over heating now it intermatint lose power with no code

From the looks of it it could be a vvt issue if your vehicle is equipped.

plz expline to my
yes it have vvt also i put my money on vvt


but what you see

If you look at the divided peaks it shows a momentary loss of compression then builds pressure again. This makes me think vvt is momentarily moving the valves. The other possibility is a set of weak valve springs causing the valves to bounce which if you use a stethoscope you should be able to hear it.

The other thoughts i have are real slim to have happened but head gasket or cracked cylinder wall which would be evident by lots of bubbles in overflow tank or swelling of radiator hoses.

Hi everyone,

Are those double peaks occuring in compression stroke?

What if you unplug VVT actuators and crank it again?