P7100 makes clicking sound then truck dies
 

I just saved a 92 cummins from the scrapyard. I got it to start and am super excited. I
took it for a test spin, ran fine then just died. I have figured out that it has a P7100
Injector Pump. It starts fine, runs then just dies. It seems to run fine but does sound a
little funny sometimes(when giving it a little throttle it sounds normal then changes like
the fuel flow is not even). When it dies it makes a click clack (sounds like from inside the
injector pump) then just dies, no sputter. I can hear one more click after it has died and
sits for just a minute then it fires right back up. if I try it right away, before the last click
after it has died, it wont start. but give it a minute and fire right back up. The only other
thing I know about it is a manual fuel shut-off. I'm lost on this thing and would take any
help. Thanks guys