My 2004 Silverado Z71 will not start. My check engine light came on, I had buddy come over and use his diagnostic. Read knock bank2. Clear the code and engine light was gone. He said let it run for a 1/2hr. Turn truck off and waited a couple seconds and tried to restart and nothing. I replaced both knock senor and harness and still not starting. Tried to reset computer by unhook both battery terminal and touch together and wait. Hook back and still no start. Im getting spark and gas to fuel rail unsure if injectors open. Spray starting fluid into intake and truck will run then shut off. My gauges have not work for years and recently the info/ odometer quit last week. Now blue squares show since not starting. Any ideas what is wrong and what needs replaced.
Also unrelated I think my 4x4 service light came on when I engaged 4 x 4 and I could not get it out a four-wheel drive. I disconnected ground and pulled fuse for 4×4 till it went by into 2wd. But 4×4 isnt working. Any idea on that? Thanks

 

The fuel injectors all receive battery voltage from the INJ1 & INJ2 fuses in the underhood fuse block with the key on. The pink wire at each injector is the power supply - disconnect an injector on each bank and check for power while a helper turns the key to the on and crank positions. Pull the starter relay to prevent cranking while testing.

If you don’t have power in both on and crank, the ignition switch is likely at fault.

The PCM controls the injectors on the ground side, so if the power circuit to the injectors is good, checking for injector pulse using a noid light is best. If there’s no pulse while cranking, the PCM or wiring is suspect.

The instrument clusters are known for having multiple problems. Use google or equivalent and search “instrument cluster repair” in your area and start making calls to determine who can fix it and what their turn around time is - it may require mailing the cluster out. The truck can be driven without the cluster, so mailing it for repair wouldn’t disable the truck.

As to your 4x4 - the selection switch and transfer case control module are both common problems, but more diagnosis would be required to determine the cause.