In another post I start in reagrds my 1984 300D running out of fuel after using only half tank. Several people recommended cleaning the screen, I did that today and found very little junk on the screen to prevent fuel delivery. My question is: If this unit is at the very bottom of the tank. What prevent the fuel delivery system from accessing all of the 20+ gal fuel.

It was mentioned if I ran out of fuel (engined died and not start) at half tank consumption, the screen is clogged and preventing the access to the remaining 10 gal the tank holds. From what I saw after removing the screen, it was a straight shoot with no chambers allocating amount of fuel to access.

I am just curious what to check next in the event with the clean screen, the car will die after half is consumed.

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1984 300D, 1972 LT1 Corvette, 2014 Artic White 3LT/Z51 C7, 2013 650i Convertible BMW, 1994 Kawasaki Vulcan, 1992 Yamaha Seca II and 1996 Dodge Ram 2500.

Return and supply fuel lines may be reversed under the hood is one possibility. The return line to the fuel tank enters at a much higher position. Was there indeed about half a tank of fuel that needed drained at the time of the screen removal?

Why I ask is the gauge may be innacurate. Also a restricted vent system on the tank may allow enough of a vacuum to develop in the tank to stop the fuel flowing.

I imagine a very weak lift pump is also a remote possibility. As the tank level drops it cannot cope for example. This is somewhat remote though.

You don't state if this is a new-to-you car or one that you've had for awhile and the problem just cropped up.

The symptom you describe is indicative of a supply and return line being swapped. It's common for those having fuel supply problems that point to the screen, to swap the two lines and see if the problem goes away.

The return line dumps back into the tank about halfway up so you would run out of fuel at about that point.

If this is a new problem and you know the lines aren't reversed, it might point to a weak lift pump. If the head pressure of the fuel in the tank isn't available to "assist" the lift pump, you might reach the point where it can't maintain sufficient fuel flow at about half a tank causing it to appear that the car is out of fuel.

Beyond that, I'm out of ideas.

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Current Stable

• 380SL (diesel)
• Corvette C5
• Manx
• Baja Bug
• F350 Powerstroke
• Auburn Boattail Speedster replica

The car is new to me, well I've had it for two months now. The fuels lines are not switched. I verified that while the screen was out, I took a fuel hose and attached to the fuel supply tubing, took the other end and submerged it in a 1 gal fuel tank and suck that dry from under the hood, the same fuel line that feed the primary filter.

I pump out 15 gal+ from the tank before I removed the filter, the tank was close to the half tank mark before I started pumping. I am going I guess i am getting the re-built lift pump kit. Thank you

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1984 300D, 1972 LT1 Corvette, 2014 Artic White 3LT/Z51 C7, 2013 650i Convertible BMW, 1994 Kawasaki Vulcan, 1992 Yamaha Seca II and 1996 Dodge Ram 2500.

Sometimes the issue with fuel pumps is a simple as sticking valves. I had that problem; the car seemed like it gained 20 hp with a full tank versus an empty tank. My engine did run on a near-emptytank, just not very well. I installed new valves and springs; the improvement was substantial.