engine and drivetrain Fuel tank/fuel supply

[toropoki]

Ok I'm still having problems with my 75 2002. Apparently the person that rebuilt the car had used the drain as the source for the fuel feed to the electric fuel pump instead of the regular going thru the top of the fuel tank. It has a large diameter pipe then hose attached coming out of the tank requiring a larger hose. It goes into a square box like filter(?) and the exit of that is a normal size (for BMW's) fuel hose going into the fuel pump. After examining the box like filter thing it shows the flow should go the other way. I don't think there is anything in the plastic box though I'm not sure. There are few markings on the box a few numbers and it's made in Israel. As some of you know I've been dealing with a fuel starvation problem after driving the car during the day while it's hot (Hawaii hot). I get no fuel to the engine until I let the car rest for about 20 mins. After it sits for 20 mins. the fuel flows to the engine (I can see the fuel through the glass filter) and again I'm off. This is what has been done so far: fuel pump changed, 2 filters changed one Bosch the other nearer to the carburetor (I am running twin webers 40 DCOE) I have an electric carter 4070 fuel pump (http://www.poustusa.com/weber_carb_pages/weber_carb_page.htm) to go in but am at a loss of how to go from the larger size fuel hose to the smaller diameter fuel hose. Is there an adapter to go from large to smaller diameter fuel hoses? This is annoying stalling out in the middle of traffic. I still need help with this.

[Napes]

If it were me, I'd begin by blocking off the drain line tank exit, go back to the original fuel supply system out of the top of the tank (the original Germany engineers sorta knew what they were doing), ditch the Israeli dust/sand filter, and get everything in the fuel supply system back to original. That may solve your problem.

This is the diagram for the ' 75s:

http://bmwfans.info/parts/catalog/114/Sedan/USA/2002-M10/LHD/A/1975/february/browse/fuel_supply/fuel_tank-3/

Bob Napier

[M3M3]

agree....don't bother fixing a kludged up system. put it back the way it was supposed to be.

[Mike Self]

from the bottom of the tank (where all the crud is) or if there's a riser inside the tank, soon as it's exposed the pump will draw air, meaning the last few gallons in the tank can't be accessed. The only time you'd draw from the bottom of a tank would be with a gravity feed system like a lawnmower, Model A Ford or an A model Fiat Topolino.

As was stated earlier, pull the tank, clean it out real good and go back to the original parts for the fuel pickup. Install one "normal" fuel filter just upstream of the mechanical pump and I'll bet your fuel starvation problems will be over.

cheers

mike