Fuel Primer pump Help - Page 2 - PeachParts Mercedes-Benz Forum

Stevo · #16 02-16-2008, 10:42 AM

Quote:

Originally Posted by ladams4

The car was running awesome then i noticed a slight rought idle then noticed the return lines were leaking so I replaced them then replaced the Fuel filter the first and the secondary the filters were absolutly Disgusting with Chunks of I dont wanna know. and the 1st filter was so dirty it was black. and now when I do get it started it sounds like a bomb clacking and it just turns off like it is starving for fuel.

Now on the primer pump when I do try to pump it leaks diesel at the bottom and even comes out the top and you can hear it sucking AIR. But could it still be sucking air if the primer pump is closed?

Thanks everyone

Sounds like the first thing to do is replace the primer pump. Next I would swap the supply and return lines
where they come together and go into steel lines under the hood, driver side. Your tank strainer could be plugged. By swapping fuel lines you'd be drawing fuel from higher in the tank. Or you could draw fuel from another source, soda bottle, what ever. That would tell you if the strainer is plugging.

Diesel911 · #17 02-16-2008, 01:28 PM

Even with a good primer pump; ounce air gets into the IP itself it is better to loosen some of the fuel injection line nuts at the injector and crank the engine until you see fuel spruting out and then tighten them back up and attempt to start. Ounce air gets into the high pressure part of the system it somewhat like a gas type shock absorber (springy). The air compresses but only a little pushes itself out of the injector the rest decompresses as to IP plunger moves away from. And the process begins again each time squeezing only a fraction of the air out. Loosening the fuel injection line at the nuts allows the whole volume of air that the IP plunger is pushing on out.

whunter · #18 02-16-2008, 01:39 PM

PART NUMBER SEARCH RESULTS WITH PRICES
Vehicle 1980 Mercedes Benz 300D
Part: Primer Pump
D2010-268357 Diesel Primer Pump Bosch IN STOCK

And here is the DIY:

Diesel Primer Pump Replacement
on the 1985 300SD
by pwogaman
11/29/04

Have a great day.