My neighbor asked me to see if I could figure out what's up with his 93 GMC half ton. It has a 350. Here are the symptoms. Hot or Cold engine when you turn the key to start the engine to the first position (not start) a fairly loud ticking noise begins it sounds like a relay going open and shut it lasts for 15 seconds or so. The engine starts with or without the noise stopping. Shut the motor down and the same sound comes back and again lasts 15-30 secs. The noise seems to come from down by the heater blower. I thought it might have something to do with the fuel pump or its relay so I pulled the fuse pump fuse but I still get the tick tick tick for about 20 second and the engine isn't running. This happens every time I turn power on or off. Very weird.... I'm an old dude with a couple old hot rods I work on and everyone in the neighbor hood thinks I can fix their car. Please help.