I recently had a similar problem on my 190E 2.6. Testing and analysis pointed to the fuel accumulator. I tested it by disconnecting and plugging the hose on the backside that tees back into the supply hose from the tank and installing a test hose on the accumulator nipple.

Turning the ignition on energizes the fuel pumps for a second and when I did, fuel ran out the test hose indicating the accumulator had failed internally and was not holding pressure. So when the fuel pumps are energized, fuel is shorted back into the supply hose from the tank and the system will not build pressure. A friend with an '82 911SC had a similar problem a couple of years ago, and it was the accumulator.

Now, here's the rub. There is no available stock of the Bosch replacement part, 0 438 170 035, and Bosch USA does not expect to have any until the end of May. Mercedes does have stock, 000 476 06 21, and the list price, $287, is about double the price of the Bosch part from Pelican.

I did find an online dealer in Kansas City who offered the part for $190 plus shipping, but they had to order it from the Fontana warehouse. So it goes from Fontana to KC and back to me in SoCal. I hope to have the part by the end of next week.

Suggest you run the same test on your accumulator and go from there. The same acculuator was used on virtually all models with four and six-cylinder CIS-E engines from '84 to '93. I'm really suprised that Bosch ran out of this part in the USA. It may be the most common CIS part failure.

Duke