Fuel system components

[Vaughn MacKenzie]

Starting at the tank what is the fuel system composed of? I take it there's an electric pump in the tank since there's 3 wires going to the top of the tank? This is on an '82 Blazer.

Then you have the line up to the engine bay where it goes to the first filter, then to the mechanical pump on the engine, then the secondary filter and finally the IP correct?

I'm helping a friend with a little hard starting (cranks for a bit before it finally fires) and has been having intermittent low power. We're wondering if there's an electric pump in the tank that has died or if it's getting air and losing prime somewhere. I saw in another thread the fuel pump has a check valve and if the IP advance piston is leaking then it can lose prime.

Another note, after changing the primary fuel filter he has hell time starting it (fills the filter with fuel before reinstalling). We are thinking either the electric or mechanical pump is dead/dying.

Vaughn

[DmaxMaverick]

No electric pump on an '82. Mechanical on the engine only. No GM Diesels have an electric pump in the tank (gasser thing). The later models have the electric pump in the frame rail under the driver side door. The wires going to the tank are for the level sender.

Sounds like a dying mechanical fuel lift pump if there are no leaks. Usually when they go away, it will drip fuel from the weep hole in the pod. They're cheap and relatively simple to replace. Leaks between the tank and pump will suck air. Between the lift pump and injection pump will leak fuel externally. On an OEM 82 the fuel routing is as follows:
Tank (sock, pickup tube, outlet), primary fuel filter, lift pump, secondary filter, [IP to injectors to return line] or [IP to return line], tank return inlet. Dual tanks complicate it and change the possible problems, but not a problem with the Blazer.