idles but no fuel pressure - lift pump question

[dieselbegreat]

I think I have a lift pump going bad or a clogged sock in the tank. Mine sits a lot for long periods and the fuel has not been the cleanest. It is now running erratically, always starts right up but when a load is put on it for more than a few seconds it will blow black and then white as it loses power. I decided to hook up a gauge to the top bleed on the filter and see what the pressure is (usually like 6psi). I cracked the valve and the engine stalled -- no pressure. It will start and run as long as the valve is closed tight. I've ordered a new Delco pump and plan on blowinig compressed air back to the tank if the fuel doesn't flow. Any tips on installing the pump?

[DmaxMaverick]

Fuel pump not pumping. Your description sounds very typical. If the IP is able to draw fuel w/o the pump working, you have NO system blockage. It doesn't take much at all to cavitate a healthy pump.

The tank sock is most often best left alone. If you blow back into the tank, it may desintegrate the sock, or stir up stuff that would not have caused problems in your lifetime. You could cause the sock to get plugged up. Pull a fuel sample and let it sit in a clear container for a couple hours while you replace the pump. Check it when you are done. Any water or sediment will settle out. I think you'll find the fuel isn't as bad as you think.

[dieselbegreat]

Thanks, Maverick.