I seem to be the only one up this morning, so I did a little research.

There is in fact a kit to recondition the pressure regulating valve. You can also buy just the o-ring. You need to tell the parts guys to look at Group 7/4 for the 280E. The parts are readily apparent.

Also, in the K-Jet troublshooting guide, it lists the following parts as suspect in hard starting as in they can leak and cause a loss of pressure.

- primary system regulator (as discussed above)

- cold start valve

- fuel pump non-return valve

- diaphragm in fuel accumulator

- pressure compensating valve. This is a gizmo that "is located at the inlet to the fuel filter" and acts to prevent the vacuum problem described earlier.

- control plunger or "o-ring of metering sleeve"

The test for this is to connect the pressure guage between the FD and the warm-up compensator (presumbly on a warm engine), and run the fuel pump for 30 seconds by turning the ignition on (you may have to push bridge the relay as well). When you turn the ignition off, you should see 2.8 bar holding steady. After 30 minutes, you should still have 2.5 bar.

__________________
Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe