1998 Chevy Suburban NO FUEL PRESSURE to start engine

Your oil pressure sending unit is tied into your fuel pump relay feed wire. Try changing the oil pressure sending unit--however, if the sending unit is good and there realy is a low or no oil pressure condition, then your problem may be your oil pump--a blocked oil port inside the motor--a bocked oil pressure sending unit port--or something of that sort. Let me know how you make out.

 Ron, being that you are changing the fuel pump, have the chassy harness fuel pump electrical connector changed. It is the plug that plugs into the fuel pump. I have had so many problems with these I cannot even began to count.  The original connectors fail when you un plug and then plug them back in. The internal electrical prongs spring open causing a loose connection. This may not be a problem at first, but I'll bet anything that in a few months your engine will not start; and you will blame the new fuel pump. This can also cause a fire because of the loose connection arcing. It is not worth taking a chance with this connector considering all the work and expence envolved.
The replacement connector has to be spliced into the chassy harness and has 4 wires on it.