Have a 1990 W350. Has been a great motor for over 200,000 miles . Now it quits as I go down the road. Tow it home, bleed first three injector lines and it starts. Think it is ok but down the road it quits again. Would love any ideas of what it might be. FSS getting power . Should I just replace it?
Thanks

 

If the problem was the FSS, is would not require bleeding to restart.

To require bleeding, you must have air intrusion.

Usually, though, once an engine is running, it takes a lot of air to actually shut down the engine, so you must have quite a large air leak.

According to your description, I don't think your problem is the FSS.

Air can intrude anywhere in the DRAW line, from the injector-pump all the way back to the fuel-tank, AND even from the plumbing within the tank.

The most likely places to look are the rusted metal lines that run along the frame from tank to lift-pump and the short rubber lines that connect these metal lines to the tank and lift-pump.

30R7 rubber line is a much better choice than the rigid metal lines.

To test whether the problem is between the lift-pump and tank, remove the rubber line from the lift-pump and route a temporary line from the lift-pump to a large jug of fuel; test run it and see if it cures the problem.

Be advised that, unless you also route the RETURN fuel back into your test-jug, it will soon draw your test-jug empty.

 

Thank you, I will take a look on fuel lines .