Not using return fuel line?

Can someone tell me what happens if I don't use the fuel return line and run a returnless fuel system? Will it hurt the pump to be running at 100% duty cycle on a returnless motor?

 

If the pump is designed to be used returnless (has a built in pressure regulator) it will work but otherwise it needs a regulator and return line or you will blow the pump or lines.

 

It’s a DW300 340LPH pump.

 

If your using the stock Tacoma housing you absolutely need a regulated return.
Doesn't your engine have a regulator on the fuel rail or was it from a vehicle with a returnless system?

 

It's from a 2004 Z06, so it's returnless. The DW pump is self regulating and starts cutting back @100 PSI. But im sure thats not healthy to be running that high of an injector pressure. Crap.

 

Yea you have to have a regulated fuel supply, most GM port injection systems typically run in the 50-60 psi range.
Fuel pressure and injector flow rate also has to be known by the engine management system so it knows how long to open the injectors to inject a guven amount of fuel.

 

I knew of someone who used the feed line as a return, added a large feed line to support the higher volume needed.