We have a 95 volvo with m11 cummins and in the last year it has developed a problem of after sitting for a few days it does not want to start. I have checked and tightened all fuel line connections. The fuel lines are plastic parker hanifan 5/8 hose. This engine does not have a check valve in the top fitting of cooling plate like some do and cummins told me they did not all have this check valve. The fuel filter is mounted to the frame side rail. A local truck shop gave me an eaton inline check valve that i installed in the inlet side of filter. I ran truck after installing this valve and let it sit for two weeks and tried starting it and it started. But after another couple weeks it would not start without a shot of start fluid. I have tried napa 3406 and fleetgard ff105 filters and always change the oring. We had it running today and it was shut down for about 3-4 hours and tried starting and it would not start so i pulled the fuel filter and heard a gurgling sound when i removed it and the filter was only a third full. I filled the filter with fuel and it started. I am a little stumped as how the filter could be almost empty with the check valve on the inlet side of filter. I have read lots of posts on this problem and wondering now if i should just replace the fuel lines from the filter and check valve to injection pump or all of the lines. Also wonder where to get this kind of plastic hose. This truck also has an arctic fox system and i am not real familiar with it. It is a farm truck and is only used during harvest and to haul our dozer around. Just fishing for any suggestions or tips as to cure this problem. Last harvest when it was running every day it wasn't a problem till it sat a few days. Thank you for any advice.
Normally I would say you need to replace ALL the fuel line, but that usually only applies if your truck has aeroquip hose. I would put a ball valve on n the suction line at the top of the tank (each tank if it has 2). Close the valves after you shut the truck off. If it starts right up after sitting, you have an air leak somewhere. You might need to change all the lines and fittings.
It may be sucking air somewhere in the supply side of the system when shut down and the return siphoning back to tank is pulling the air into the filter. You might try putting three or four psi of air into the tank(s) if you can seal up and vents (do not go any higher on pressure, something will pop) and look for leaks between the tank and the fuel pump.
At my prior job we had ready mix trucks with Cummins [and everything else] a few of which had no check in the cooler from the factory, all would be fine till one day they would be hard starts. A trip to the bone yard would bring a check valve and it would cure the problem. Don't know why it would be fine one day then hard start the next but it would. I never had time to look for air leaks[think concrete on everything] but went with the quick fix and moved on to the next crises/ drama that I know you all fully understand.