I've got an 84 K10 with the 6.2. Driving down the road today it made a pop sound then quit. Thought I threw a belt or blew a hose off, all that is good. I haven't been able to start it since. I pulled the fuel return line from the top of the IP and put a clear hose on it and spun the engine, did not get any fuel out of it. I have fuel getting through the filter to the fuel line that feeds the IP. The start solenoid on the IP is getting power, I can hear it click as I plug and unplug the power wire. Truck usually starts fine, glow plugs work fine. I have been searching forums for a way to test the IP to verify my suspicion but have not found anything "definitive" yet. Any help will be greatly appreciated!