1995 chevrolet tahoe will crank but not fire. how do I test the cpu?

SOURCE: 1998 Cevy tahoe won't start

I had a similar problem and took my 98 Tahoe to several shops before it was fixed. The fix only came as a result of my own research and persistence in trying to solve the problem. After the engine starts and runs for a short time, try turning the engine off and then restarting it after about 10-15 seconds. See if it starts up with no problem. If so, let it run for a short time, and turn it off again. This time, let it rest for about 10-15 minutes before trying to restart it. If the problem is present, and hard starting is obvious, have the fuel pressure regulator valve checked, as well as the fuel pump. The regulator valve looks like a 15 cent part in a plastic bag, but is a real headache to change. I am not a mechanic, but I was told by my mechanic that it sits down behind the carburetor and everything on the top of the engine has to come apart to get to it. It seems that if the valve goes bad, the fuel that remains in the fuel line, which is ready to feed the injectors, trickles back into the tank, and the head pressure is lost. The hard start is caused since you have to prime the system all over again after the car has sat idle for a awhile. The fuel pump may be fine, but in my case, it also was not helping to maintain the fuel in the line, and it completed the failure cycle by allowing the fuel to drain back into the tank. Either you or your mechanic may be able to make a few tests for this problem. It drove me up a wall for about six months until I finally forced the issue, and proved my point to my mechanic. Good luck

SOURCE: i got a 1999 chevrolet tahoe. when i put the key in the ignition the head lights,and the dash light comes on but it won't even turn. i change the starter and got a new battery and it still won'

did u check your fuses in the fuse box if so maybe your computer is bad just had that problem in my wife dodge car replace pcm run great. When you turn the key does the check engine light come on to do the self check if not it most likely your computer bad.