My friend has a 1999 2500. Sometimes it will not start. You can hear the fuel pump. The starter is spinning the engine just fine but it doesn't hit a lick. Sometimes you try it 3-4 times it will start right up. We have tried to wiggle the wires and pulled the connectors loose from the PCM but none of this seems to help. Any ideas?

 

Even if the fuel pump is running, it does not necessarily mean that it is pumping. 1st off do the ignition key trick and pull any codes. but i would definitely check fuel pressure

 

Tractorguy is correct, many times the lift pump can be heard running, but isn't pumping any fuel.
You can't do the key trick on '99s, you'll have to scan it.

 

Thanks guys. we will try what was suggested.

 

loosen the fuel line where connects to the vp44 and crank the engine, if no fuel at point then go back to where the fuel line connects to the filter,if no fuel at that point then check the fuel line to the tank, it could be sucking air. if the line is ok then make sure there is enough fuel in tank ......if at that point every thing is ok replace lift pump