GMC Troubleshooting Questions? Ask a Mechanic for Answers
If the engine turn over strong but want start you need to check for codes first, if there are no codes more tha. Likely the problem is fuel related such as a bad fuel pump, either check the fuel pressure (should read 55-60) or spray a choke spray in the throttle body or brake booster hose, if it runs then the problem is fuel pump or fuel injectors not turning on. I hope this helps, please give a positive rating and reply back any other questions. Thanks
I see give me About 30 min to look at a schematic of your starting system.
It would be easier if we talked live and you had a voltmeter and test light handy. First make sure your battery is good. Have someone turn the key to the start position, check for power on fuse IGN E, IGN A, and crank fuse. Let me know the results