98 ss60 12.7 ddec4 fuel issue

Check valve in fuel return line, check valve in inlet of Davco, sucking air at some point.

My first thought is always the return line check valve, and would assume that with full Davco housing.

 

Most likly somewhere on the Fuel Suction lines going to tank pinhole that cant be seen with the Eye

 

Get a lift pump like fass/air dog and that will never happen ever again....I have one on my truck and its night n day difference.

 

I noticed a better delivery of power when needed, easier engine start up especially when its 32 below, smoother engine operation due to less air going to your injectors, filters can last up to 20k intervals, if your easy on the throttle and ride around 65mph you see atleast .3-.5 mpgs increase.

 

Yeap they sell a heater kit for it also.

 

I had a 1998 Century with the Series 60. Mine lost its prime due to the fuel shutoff valves. Truck had long rods that you pulled to operate the valves. The weight of the rods pounded on the valve stems over the years, damaged the seal and let the air in.

 

Another good thing about having a lift pump is that it always primes the fuel system before starting the engine and adds from the top of the tanks an extra fuel return.