I recently purchased a 97 Sierra that has been converted to dual fuel(which I know nothing about BTW)the truck ran when purchased but leaked massive amounts of water so I replaced water pump and lower hose .then she wouldn't start so I tried all quick fixes I could think of ( starting fluid and so on ) but due to the dual fuel thing figured I'd just replace fuel pump on gasoline side and still nothing no start actually I don't even hear the pump engaging and yes the propane system is temporarily unhooked due to having to get to the in tank fuel pump so my question is help please

 

I would check the fuel pump relay. If the vehicle is dual fuel, there still needs to be some type of switch to select if you are running from gasoline or the propane tank in the back. So I am betting the fuel pump is disabled electrically in some fashion. The propane would have to enter the engine in a gas form at the throttle body and/or fuel rail somehow, bypassing the normal fuel lines coming from the gas tank. I would be looking for some type of switch under the hood, for the fuel source, and for a switch (or missing relay of fuse) that is disabling the gasoline fuel pump.

 

If it ran before yhou replaced the water pump, retrace your steps and see if something was left unhooked

 

Yes propane runs in at the fuel rail and no no missing or unhooked anything

 

I have retraced everything and nothing seems to be different no loose wires no missing parts