OM603 not starting, IP or Lift pump or both?

[ah-kay]

My friend's 300SDL is not starting. The symptom was that it would not rev over 2000rpm. It dropped back to idle. Then it did not start at all. His story so it may not be correct.

I suspect it is the IP/lift pump as there is no fuel coming out of the injector lines ( I loosen the injector nuts ). We put the fuel inlet line into a clear bottle of diesel and crank the engine. We do not see the diesel being sucked up.

Where is the lift pump? Can it be overhauled? Any ideas?

[TMAllison]

Start with fuel filters and tank screen. Lift pump and IP's are both low fail items.

[ah-kay]

I have told primary and secondary filters have been changed. Tank screen is out of the equation as we used a gallon jar for fuel under the hood.

[Govert]

If you use a jar of diesel, put in the fuel inlet hose in the jar and let the outlet hose of the lift pump drain in the jar, you should notice fuel being pumped if you start the car. If not, the lift pump is not working. Maybe the valves are broken.

[BoiseBenz]

Originally Posted by ah-kay

Where is the lift pump? Can it be overhauled? Any ideas?

It is the extra little "wart" on the side of the injector pump, with fuel lines going to it. It is simply a cam-driven plunger, with "in" and "out" check valves. Yes, it can be serviced.

[Diesel911]

Originally Posted by ah-kay

I have told primary and secondary filters have been changed. Tank screen is out of the equation as we used a gallon jar for fuel under the hood.

If there is something contaminating the Fuel a brand New Fuel Filter can get plugged in a matter of minutes. Changing the Fillter because it is the most likely cause of Fuel starvation is just good trouble shotting.

2nd best would be to disconnect the Fuel Supply Line between the Fuel Injection Pump or theFuel Injection Pump return line and see if when you crank the Engine there is a resonable volume of Fuel coming out.

[ah-kay]

It is fixed. I asked him to put everything back to stock. It was running on WVO with all the lines butchered up. He found loose hose clips and tightened them all. Use a bottle as feed under the hood and cranked. It started after some cranking. So he is good to go.

[TheDon]

For future reference note that if a 603 has been run out of fuel it can be a pain to get the system reprimed. Some here have run their battery down cranking to get it to reprime.

I almost ran into that issue the first week I had my 300D. But if you prime the injection and hard lines by using the small bottle method like you did it helps tremendously since the lift pump doesn't have to suck all of the air from the supply line. .