I changed the fuel pump on a friends Jimmy and now the truck won't start.
The pump is running and we verified fuel is getting to the rail via the fuel bleeder thing in the engine bay (at the back of the engine, by the fire wall).

The truck will start, but only for 5 seconds, if we give it a quick spray of starting fluid in the intake.

One thing that may be causing this is the old pump had a small nipple next to the main fuel supple nipple on top of the pump.
The new pump didn't have the smaller nipple. Does anyone know what that small nipple is, or what it does?

Thanks in advance,