Have been chasing this issue for some time... any help or suggestion is much appreciated.

Car not starting. Narrowed to fuel pumps not running. Specifically, pump doesn't prime when ignition is turned on/cranking. On a very rare occasion after many many times turning ignition on and off the pump will audibly power and prime after which the car will start and run fine until it sits for some time after which it will not start again. No CEL, OBD codes or other warnings...I do not have access to Star Diag.

Due to fuel leak at cracked plastic connector on left pump (fuel smell issue!) and suspicion of issues with right pump I replaced both especially given mileage (75k). General performance was MUCH improved and fuel leak resolved. However, starting issue remained. I replaced fuel pump relay in rear... same results. I have checked voltage at 4 wire connector to right pump...no power when helper cranks engine. HOWEVER, when I disconnect the plug and manually apply 12v to the pump directly it immediately starts pumping and the car starts and runs perfectly. After idling for a period, re-checking the voltage at the connector yields 14v. Once voltage is measured I can re-connect connector and pumps power and car starts and runs normally...again, until car sits for some time and starting problem returns.

Only other suspicion/concern is that the shielding on the 4 wires into plug on right pump are split from being bent under metal pump cover. Suspect this happened after dealer finally replaced tank (fuel leak/smell!!!) It is only the shielding and the wires appear fine and obviously carry voltage after above procedure. I have taped each to assure no shorting.

Just FYI...I replaced CPS prior to this current issue due to starting problems and OBD code. That particular starting problem was resolved with new CPS.

Thanks! Again, any help is appreciated.
Doug

2005 W211 E55 wagon

 

SOLVED...https://mbworld.org/forums/w211-amg/...sues-help.html

Thanks to all who helped me with information!! Much appreciated!!