CIS-E, 87 5000S, NO Fuel to Injectors, HELP

[BinsuJiro]

HELP!!!

No fuel through CIS-E Fuel Distributor to Cylindar Fuel Injectors on 1987 Audi 5000S. The problem started with some minor hesitation over several days. Within a day or so, the system failed completely on the NYS Thruway within 35 minutes of refueling and 45 minutes of start up. I am getting NO fuel out of the Injector Outlets of Fuel Distributor.

There is fuel to Cold Start Injector, but DON'T HAVE TOOL TO MEASURE SYSTEM PRESSURE or AMPERAGE TO THE DIFFERENTIAL PRESSURE REGULATOR. Fuel pump runs during cranking, and when Fuel Pump Relay terminals are bridged and I manually lift the Airflow Sensor Plate inside the Air Filter Housing, the Fuel Injectors do not charge. The Air Filter was relatively new; I replaced the Fuel Filter.

Adequate spark from plugs. Hall Sending Unit-OK...new plugs, new spark plug wires, new distributor cap.

FUEL TO: Distributor-Yes; Cold Start Valve-Yes; Return Line-Yes; Diaphram Pressure Regulator-Yes...tried second DPR and got same result...I also tried replacement Differential Pressure Regulater with no change. NO fuel out to Injector Lines. I took the Fuel Distributor out and inspected it; the plunger moves freely and smoothly and all the orifices and passages, as far as visible, are absolutely clean.

I am starting to suspect a clogged Fuel Pump Screen from either bad gas or contamination in the Fuel Tank.

Can anyone HELP with this problem?

Thanks in advance,
Vince