Any way to test the injection pump? My brother was given a 84? GMC 3500 with 6.2l today. It has not been run in over a year. We unpluged the IP and cracked an injector as well as the fuel line going into the IP. We got fuel at the IP then hooked that back up. Turned her over and got fuel to spirt out the injector for a second then nothing. We have cranked it over for a while with no results. Amazingly the starter and cables are taking this way better than I thought they would. So any way to test the IP is running? It sounds like it is doing something.