Originally Posted by kerry

I think it will start within a few seconds but much longer and it just cranks. Lift pump seems fine under all circumstances, at least it always shows pressure on the gauge. If it was an air leak problem, it seems it wouldn't start once it cools down either.
I should add that according to what I've read on numerous sites, problems with a hot start are typical of a worn IP. Here for instance:
Kennedy Diesel
The previous owner, by all appearances, was a stand up guy. I doubt he had tried any additives. He told me things that were wrong with the truck that would not have been evident otherwise.
One thing I don't like about this GMC is that there's no simple way to test the system with an alternate fuel supply. Metal lines in and out of the lift pump and the rubber line to the fuel filer very hard to access between the bell housing and the firewall.

Not sure what you mean by 'test light to B+'.

Originally Posted by kerry

John, you were getting hard hot starts with bad injectors? What about the big difference in starting between the two tanks of fuel? I can't think of any way to explain that besides a worn pump.

Originally Posted by vstech

I thought you were looking for alternatives to try before getting a pump.

.