My son has a '92' 240 that has a problem with the fuel pump. The car will not start unless you send power by shorting from a 12v fuse to the fuse feeing the pump. The car will run fine, however I would like to know if there is a sensor that I can't see that is telling the power not to send.

 

Have you checked the fuel pump relay?
What doesn the engine speed sensor look like?