Hi, this is my first time posting on the forum. I have had an 85 federal 300D for a year or so now and have been learning how to repair and maintain things as I go, mostly by searching and reading this forum obsessively so thank you all for the wealth of knowledge on this site. I was doing a diesel purge the other day and realized my fuel lines appear to be routed differently than all the examples I have seen in OM617 photographs and diagrams.

The flow of fuel goes: the hard supply line > into the secondary fuel filter (screw on canister) > to the primary fuel filter (plastic inline filter) > to the lift pump > then there is a small hose coming out of the lift pump and looping around back into the IP.

So basically it is flowing into the secondary filter first, then to the primary filter and then through the pump before going into the IP. Rubber hose and clamps have replaced the lines on the banjo fittings attached to the secondary filter, done so by PO.

Is there any reason the PO would have setup the fuel delivery to flow this way or could it potentially be user error? The car has been running this way since I purchased it without any noticeable issues.

I should note that this car has the "Greasecar.com" Mercedes system kit installed by PO though it is currently disconnected and bypassed. I was wondering if the rerouting of fuel lines could have something to do with the SVO kit but it has its own independent fuel tank and filtration system so I have no idea. Any input would be great!

Thanks!!

Did some reading on the alternate fuels forum and it is definitely some rerouting to accommodate the grease kit. The fuel lines for the kit had been removed previous to me owning the car so I had nothing really to go on visually. Next step is to remove the kit completely and get back to stock. Apparently sometimes the banjo bolts on the fuel filter are closed up with JB weld to use the kit...lovely...

Your fuel lines should go like this:

Hard line from the tank -> "small" fuel filter -> fuel pump (back fitting, flywheel side) -> "big" fuel filter (arrow in) -> ip (going from arrow out of the filter to the fender side of ip) -> top of the fuel filter (from engine side of ip) -> hard line fuel tank return (through a cigar hose)

Thanks christuna for clearing that up!