617 losing prime overnight
 

The past few days my 300SD has been hard to start in the morning after sitting overnight. As I crank it after pre-glowing it will catch on one cylinder then two, three and will eventually smooth out if I keep the accelerator down for a few seconds. It feels just like the few times I have run one of these diesels out of fuel, after hand priming it takes some cranking to get fuel back in the IP and up to the injectors.

A search showed that there is a check valve somewhere in the IP, but I could not find where it is located or how to check it. I have checked my pre-filter in the morning and it is still full of fuel, but I have purchased new rubber fuel line anyway. I also have a set of new crush washers for the fuel lines with banjo fittings, but am hesitant to install them because I am afraid I will crack my brittle old clear fuel lines

Thoughts?

I just tested my glow plugs and found that #5 is bad. I will replace it, but I don't think it is the whole cause of the hard start. I have driven this car with a bad glow plug before and it was not this hard to start.

Lift pump can either be replace or use a faucet electric pump.

Brian, this guy got a Bosch feed pump rebuild kit, but didn`t say where he got it but does have the part#.

www.peachparts.com/shopforum/showthread.php?t=215770

may not be your problem, but sounds like a check valve gone south.

we had a truck with a small cat engine that would loose it. turned out to be a fuel line that was sucking air.

Charlie

This can be a problem associated with the check valve incorporated into the return line banjo on the back side of the IP (toward the block). The valve is intended to maintain a pressurized reservoir around the elements so there's no air pockets in there when the engine turns over to start. Alternately, it could also be the lift pump check valve on the other side.

From what I have read on this Forum the Old Style Hand primer is most often the source of air leaks into the system.
When I had an air leak it turned out to be the Hoses that hooked to the Plastic Primary filter were hard. You could tighten the clamps but you were still able to twist the Primary Filter inside of the hose. Changed the 2 Fuel Inlet Hoses and the problem went away.

I have the new-style primer pump. I replaced the fuel lines to and from the plastic pre-filter today. Hopefully that will fix it. If not I'll try the check valves. Are the check valves a dealer only item?

Half their cost
 

That kit is over priced.

Look at FastLane less than half the price.

MB# 0000900210
http://catalog.peachparts.com/item.wws?sku=0000900210



Use the pictures on the following thread to figure out how to install the kit.

OM617.951 and .952 Lift pump Repair kit W126.120 300SD W123.133 300D
http://www.peachparts.com/shopforum/showthread.php?p=1461282

yes, possible
 

Fuel injection pump starvation with good a good lift pump
http://www.peachparts.com/shopforum/showthread.php?p=2133911