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New to the diesel world. Started with an older 7.3L IDI. It is a '93 non turbo. It has a fuel issue I'm unable to chase down. I bought it after it had been sitting for a while. The front tank didn't work and it would stall out on the back tank after driving. The water in fuel light would come on shortly after the fuel filter light would come on and she would die. Turn it off start it again (after many cycles) and she would start again run for a bit and then die. Not knowing how long she sat and the condition of the fuel in the rear cell I decided to start with the front fuel tank. Sender rusted through and tank had some rust. So I replaced both. Turned it on ran on the back tank and switched to front tank. Ran for a bit at idle then died. I disconnected the rear tank from the sending unit to ensue I was drawing good fuel from the new tank. I then changed the fuel filter and water separator. Bled the lines and started up again. Water in fuel light came back on then fuel filter and died again. So after: new tank, sender, filter/separator I'm no closer to running. Any advice would greatly help! How do I test the fuel pressure, where do I test at with it having 2 pumps and what kind of pressure should I have?

Thanks for your time!!
 

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To start with, get a bucket, and some clean fuel hook it up to the suction side of the lift pump. With a fresh fuel filter start it and see if it runs like it should. Chances are that both of the tanks need to be cleaned out, or replaced. To check fuel pressure there is a schrader valve at the top of the filter housing. the pressure should be around 4 PSI at idle. If the water in fuel light comes on, is there actually water in the fuel? If not, then the sensor is shorted. Filter light means generally that it isn't getting fuel through the filter, I also have seen it happen when the fuel lift pump was failing.
 

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It's a bit confusing on just what fuel system you have.

You should have just one fuel pump (lift pump), it's mechanical, operated by the cam shaft. There is no fuel pumps in the tanks. You say you have 2 fuel pumps, it's possible someone has added an electric pump. Explain.

The fuel senders should have a foot screen on them, commonly know as a shower head.This fits every Ford fuel sending unit from 83 to 2016, Van or truck.
Ford E Series Vans Excursions Diesel Engine Fuel Tank Sending Unit Filter | eBay

From what your saying about stalling and several cranks to get started again, your sucking air and running out of fuel, the IP will pump fuel until the filter is half empty, that's why the filter light comes on, the filter vacuum switch turns the light on.

As far as the WIF (water in fuel) light coming on, open the drain on the bottom of the filter and check if you actually have any water.

OEM fuel system is like this. The lift pump sucks fuel from a tank selected (front or rear) by the FSV (fuel selector valve) mounted on the frame, fuel is pumped thru the filter to the IP (Injector Pump), the IP supplies Hi pressure to the injectors, excess fuel from the IP is routed back to tank thru the return lines.
 
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