Hello there, after last week when my Xterra would not turn over, we figured out it was the timing belt with stripped teeth. me and my dad just replaced the water pump and timing belt on my 2000 Nissan Xterra 6-cylinder SE, after replacing these we went to do a compression test and are only getting 60 psi on each cylinder. As we know this is not what we need because the chiltons guide says we need at least 140 psi. we are wondering if it because of a broken valve (hoping not) or could it just be because we are testing on a cold engine? Any Help would be greatly appreciated. I just got this car around a year ago and it is my first and only car.

You'd really need to do a leak down to determine, but typically it's more important they are the same across all the cylinders (typically +/- 10psi). The psi will always be different from carbon build up, worn rings, etc.

If it was valves, it would have to be more than once since all of the cylinders are showing that PSI. Is the tester you're using a screw in type or a push and hold down type? If it's the press and hold and you aren't holding it down hard enough or not straight that can allow some pressure to escape. You need to really hold it down and kick it over a few turns to get a good reading.

A leak down will at least allow you to hear where the air is leaking to (you'll hear it out of the intake or exhaust if it's a valve, into the crank case if it's the rings, etc)

Are you sure you set the timing right? if your getting that on all cylinders I would figure its related to the belt timing. if it were only on one cylinder then you would probably have a bad bent valve. it is possible that all the valves are bent but not likely. check your timing marks again.

Yeah, since you're reading the same exact thing on all cylinders, you've probably got the timing marks off. If it's off on the driver's side cam, then you're distributor timing is way off too. So I'd take the upper cover off, verify the cam marks line up when the tdc mark is on zero (may have to spin it over a complete revolution to get the cam marks to come up to the top) and go from there.

I'm going to go out on a limb and suggest that you're off by a tooth on the crank gear. It would effect both cams equally, giving you messed up compression all around vs. just one side or the other (like if you had only one cam off time).

I forsee a teardown back to the timing belt.

Also, just a hint here that I don't go sharing all over the universe.

If you have the radiator out, everything on the front off, with just the timing belt on, you can start the vehicle for a second or two. Especially if you haven't messed with the distributor. Make sure the tensioner is adjusted and tightened down. Then start it. I don't let them run for any longer than a two count, but if you're uncertain and you're tearing it back down, then I'd do that.

Or you can leave the compression checker on number one cylinder, crank it over and see what your compression is after rechecking that your timing belt is on correctly.