<blockquote><font class="small">In reply to:</font><hr>
when do you have to run a return to your tank, is this just for Fuel Injected cars ?
<hr></blockquote>Yes, it's just for fuel injection.
The deal is that the pump has to put out much more than the system will normally need in order for the injectors to do their job properly. The excess fuel has to be returned to the tank so a regulator is used to keep the pressure at the injectors where you need it and all the rest goes back.