Today I opened the vent valve on the fuel conditioner housing and turned the ignition on to activate the electric fuel lift pump. I watched the drain hose until only fuel with no air bubbles came out.

After starting the engine, still it will idle momentarily and then die. This makes me think it is an air leak somewhere before the fuel filter.

Tomorrow I will take my bottle of diesel fuel move it behind the lift pump and then behind the primary fuel filter to locate the air leak.

How low can I test the turbo to see whether or not it's working?

1986 Ford Ranger 2.3l 4d55t Turbo Diesel 4X4 w/ 5spd