On the C, I have not seen a check valve problem yet. I would check the small green fuel pump relay in the trunk. Also, I have seen the fuel pumps fail and over-voltage relays.

------------------
Benzmac:
Donnie Drummonds
1991 GMC Syclone
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM