I had found that thread indeed. "Buy original pump because of internal valve needed for djet system" i concluded. Having had lots of Mercedes diesels and still do, i only like them because of reLiability and low fuel consumption. Well i like the look of the sl and w126 123 &124 i must say. But as far as rust issues i don't like them at all and gas cars i just don't like period because a car to me must be reliable above all else. this sl has no rust so i like it for that, but i really don't trust it and never will, being a gas car. MeaNing I'll sell it and would rather not lose money by throwing more parts at it or keep and install the 603 our 602 i have laying around. ..nice reliable motors, no electricity needed, pump lasts as long as the engine. ..

Mind you, this is a nice SL.92.000 original miles. .
The weird thing is that it ran fine with the dual fuel pump set up. After a couple miles the junk from the fuel tank came loose as it had set for a long time. That i think killed the pumps, Well they work but i suspect don't put out enough pressure to make the injectors squirt correctly. Or at all.
Sigh yes I'll go get a fuel pressure gauge. ..