Rudeney

Check the fuel pump for both pressure and current draw. At the Schrader valve on the fuel rail, pressure should be between 3.7 and 4.2 bar (54 and 61 PSI). At fuse 4 on the rear SAM, check that it draws between 4 and 9 amps.

GezaBMX

Thanks Rodney, will check once I get the car back, hopefully soon.
I didn't check it with a pressure gauge but there was literally the smallest of hisses so it was definitely not between those parameters. Was thinking that it could be the fuel pressure regulator inside the filter and that is why it doesn't hold the pressure once the engine is stopped.

GezaBMX

It's been a long wait but finally my car is ready They have done a really nice job with the paint and body work. In the meantime I upgraded to a facelift bumper since I found it for the same price as the pre-facelift . Yesterday I changed the fuel filter and finally my car starts first key, no hassle, no delay. It was a bit of a pain in the rear to change the filter but it was worth it. This is a huge monkey off my back!

michalk

My car has the same symptoms that you reported. But I'm driving an '04 E55 AMG.

I ordered an SDS system and am going to troubleshoot it, but may just spring for the fuel filter anyway.

GezaBMX

I chased the problem from the wrong angel at first, then I decided to change the filter since it contains the fuel pressure regulator. It was money and time well spent, now it fires up almost instantly after I turn the key.

You may still check the fuel pressure valve to see if you have pressure, if it's down then I would recommend checking the filter.Good luck, hope you get it fixed soon