300d fuel starvation - PeachParts Mercedes-Benz Forum

blhfla · #1 11-18-2006, 01:05 AM

I've been sucessfully running WVO through a Plantdrive 2 tank kit (start/stop on separate diesel fuel lines) for almost 10k miles with fuel starvation issues only when a filter was clogging (usually the diesel secondary), and usually as a result of insufficiently filtered oil (fuel). Recently I've had algae (I suspect, as it is a green sludge) in my VO fuel processing barrels that I treated with an algaecide from a pool supply store. Today the car was acting like it had a clogging diesel filter again even though it was replaced a couple days ago, so I ran on diesel instead of VO but 5 minutes later it lost power so it could not maintain highway speeds and eventually stalled. AAA saved me and once home I replaced the diesel filter again and ran only on diesel (the diesel and VO fuel lines are separate except between the switching valve and lift pump - about 24 inches - they are shared). It ran OK but after about 10 minutes same symptoms - would barely run 40MPH then it struggled just to continue running in neutral with my foot buried in the floor. It stalled and a couple minutes later I got it started again and returned home under "normal" power but at slower speeds (<40MPH). Later I started it and it ran for about 15 seconds and died. The secondary filter "shows" fuel in it but the engine REALLY has to be coaxed just to maintain 1000 RPM at full load.

Tomorrow I'm going to blow out the fuel lines with my compressor and if that doesn't help I'm attacking (replacing) the lift pump, as with clear lines and a new filter but no fuel delivery what else is there to accuse? Any thoughts/possible solutions appreciated as I'm running out of options.

blhfla · #2 11-20-2006, 05:56 PM

I didn't have the opportunity to blow out the fuel lines, but I did get it started and disconnected the diesel return line from the secondary diesel filter and noticed no fuel was coming out at low RPM but running under higher load caused fuel to come out the return line. It would rev but still didn't feel strong. The primary filter has no visible evidence of air in it. Is it possible for the lift pump or injection pump to just be weak and fail intermittently then work well enough to allow the engine to rev?

Matt SD300 · #3 11-20-2006, 06:26 PM

Quote:

Originally Posted by blhfla

I didn't have the opportunity to blow out the fuel lines, but I did get it started and disconnected the diesel return line from the secondary diesel filter and noticed no fuel was coming out at low RPM but running under higher load caused fuel to come out the return line. It would rev but still didn't feel strong. The primary filter has no visible evidence of air in it. Is it possible for the lift pump or injection pump to just be weak and fail intermittently then work well enough to allow the engine to rev?

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