Hi Folks,
I am new to the forum, and hope that one of you kind people might be able to help with the following issue.

My 97' E320 (Manufactured 01/97) has extreme difficulty starting, particularly when it is cold outside (below 70 degrees) or the engine is cold. When the temps are warm (engine or air temp) the car cranks and starts most times without difficulty. The car never has difficulty cranking, but it might take 6 or 7 attempts (15 to 20 seconds each time) to start the car when it is cold. Once it is started, it runs fine. I have changed the Fuel Pressure Regulator Valve, the Fuel Filter, and the Fuel Pump Relay (K40 Relay Module), and none of these "fixes" solved the problem. I am hesitant to install a new Fuel Pump without knowing definitively if that is the problem. Once I install it, I cannot return it if that was not the problem.

When I tested fuel pressure with pressure guage, I either get good pressure (45 psi) or zero (0) pressure when I turn the key to ON. I have also placed a multi meter on the fuel pump electrical posts, but I am not getting any reading of voltage when the key is turned ON; yet, the car will start after several attempts.

I have queried "Ask a Mercedes Mechanic", but his suggestions (listed above) did not work.

Any thoughts or suggestions would be greatly appreciated.