I have a 7.4 liter K2500 1996 Chevy Suburban LT, once it starts the engine runs smooth, though it cranks over for about 10 seconds everytime before it starts (ie I turn the key for at least 10seconds before I hear a vroom). It does start and run everyday, cold and hot starts seem to be about the same. It doesnt seem to matter if we drive short or long distances (2mi or 30 miles), the start afterward is about the same. Battery has been tested. The truck has never stalled once it is running. One mechanic mentioned that it runs beautifully (once it is running). Upon his advice, I changed the fuel pump (it wasnt holding pressure) and I have changed the spark plugs. The truck only has 106k miles, and had the distributer cap changed in 2013. Once it is running, the oil pressure gage indicates that my pressures are fine, but when I initially put my key in, the oil pressure registers at 0. I changed my oil 1 month ago, and I regulary check my oil level. Please help.

 

Sounds like fuel pressure and flow have back flowed and drained in tank.
before starting in the morning again, see if fuel lines up front have fuel and if they are under pressure, then connect a pressure tester to see if it indeed fires up AFTER the fuel pump primes.


I had a similar problem on another brand and I found if I turned ignition on for 5 seconds and allowed pressure to prime lines it would start right up......YMMV

 

This sounds plausible, I will have it checked out. IF this is the case, what can be replaced in order to maintain fuel pressure so that it doesn't drain back? The fuel pump is brand new.

 

There is a check valve assemble built in somewhere, I forget where, However, if I remember correctly its very expensive.

 

the anti-drain back check valve is part of the fuel pump. If the pump is old replace it. Some people source a check valve ($20) and mount it externally near the tank on the fuel feed line.