99 Ram 2500 4x4 5.9L Gas- truck died on the road...towed home. Fuel pump not powering up....replaced the fuel pump and pump relay. I have 11.5 volts at the pump, and a good ground. I have spark and compression, Wont fart with starting fluid in the throttle body. ADS relay is clicking. pump turns on if an external power source is applied, but truck wont start. Is there some modual keeping it from starting ? scratching head here...Thanks!

 

So the pump does not run a second or two when you turn the key to on?

 

no it does not run at all....when i turn the key on i get 11.5 volts, but the pump will not prime. I get a constant 11.5V and a good ground. I thought i read somewhere about a fuel shut off module that is supposed to cut out the fuel pump if the engine does not start within 5 seconds. But i cant find any other info. Its acting as if something is not allowing the pump to start.

 

Try swapping the ASD relay with the horn relay for instance and see if there is any change. Also, you can try unscrewing the pre cat o2 and see if it starts.