This 2002 Olds Alero came in with a crank but no run condition. I suspected anti theft problem but I changed my mind after no anti theft related codes were stored. In fact the only engine code that was stored was for an a/c clutch relay circuit problem. So I went about the normal checks for fuel and spark. Spark was present, fuel pressure was present but fuel pulse was not just like an anti theft problem.
I checked for power at the injectors and it was present. I decided to see if I could fire the injectors with may scan tool (Tech 2) and I could. I went ahead and cycled each injector while I was there and each one was okay. I tried starting the engine after firing the injectors and the engine ran fine! I shut it off and tried again, the no run condition was back.
What the heck? After doing some research I found one reference to a no run condition related to an a/c fuse being blown. No, it couldn’t be? Yes , it was! I replaced the fuse and the engine cranked and ran fine. I turned the a/c on and the fuse blew after about 10 minutes. The compressor clutch has a short in it.
A lesson to all of us, do not over look the simple, obvious things even if they do not seem to be related. Turns out this fuse also supplies power to one leg of the BCM and was inducing an anti theft scenario with no anti theft code. I should mention that as soon as the fuse was replaced an anti theft code popped up.