[Robznob11]

Originally Posted by Overdriven

If you look at the stock 3500 express fuel pump module it has 2 electrical connections. One is for the fuel level the other is for power to the fuel pump. The weird thing is the stock fuel pump module has what appears to be a return fitting on it.

Either way, the ecm doesn't need to be connected to the fuel pump. In fact because the ecm uses PWM for the fuel pump it's better to have the fuel pump run off a relay and not the ecm. Most aftermarket fuel pumps don't like pwm power and will burn out, including Walbro's.

Your engine is setup for a returnless so there is no provision for a return on the fuel rails. This means you need a fuel pressure regulator before the stock fuel rails. This can be in the engine compartment or close to the tank. You can go aftermarket or with the popular vette filter/regulator combo. If you're planning on a high HP build, forced induction, you'd be better off swapping the intake or aftermarket fuel rails to go with a return fuel system and the regulator mounted to the rails or at least in the engine compartment.

In general you should run any electric fuel pump off of a relay and trigger the relay with the ecm or key. There is no way there is enough power to efficiently run a fuel pump off the ecm. Stock setups are pi$$ poor design and looking for a failure from there birth! I prefer to trigger the pump off of the ecm because it cuts power when the engine is not running. I have the racetronix pump with hot wire that will overcome my regulator and stay running if the engine is off and key was on, probably would not hurt much if not left for long but when the ecm already has the provision to control just such a issue, you may as well use it.