Hey Everyone,

I just got a compression test on a '94 Yukon, and teh dealear came back with 500 to 490 on all cylinders. I thought 400 was the highest? Am I missing something?

huh? can it be ran with the turbo or something?

400 is where a healthy engine should be but gauges do go bad. The main thing is that the cylinders are even. A bad gauge might show an errant reading but it would show the same reading for cylinder balance. Sounds like a good engine.

There is no number to say all engines will not make more than this number.
You are looking for balance between them, and at a minimum of 350psi.
FTR, my 6.2NA checked 575psi, when I done injectors about 100K ago.

Hey Everyone,

I just got a compression test on a '94 Yukon, and teh dealear came back with 500 to 490 on all cylinders. I thought 400 was the highest? Am I missing something?

My guage give a reading of about 400# to 420# on most engines. Like the guys are saying, all guages read differently. What you are looking for is balance. What you hope not to find is one or two that are 100# less than the rest!!