Mercedes Benz repair: My car wont start, mercedes benz 190e, 1987 mercedes benz 190e

Question
ITs a 1987 Mercedes benz 190E 2.3Lt. i would like to know why my car wont start?  ive been told that it might be my Fuel pump relay switch, well the reason i say that is because ive allready checked the fuel pump on the car and its seems to work fine i would like to know what may be the problem.. Thanx for your time

Answer
Educated guess:
One or all of these parts can be the issue.
:Overload Relay
:Fuel Pump Relay
:Catalytic Converter


PART NUMBER SEARCH RESULTS WITH PRICES
Vehicle 1987 Mercedes Benz 190E 2.3
Part: Overload Relay
Note:  
Aluminum cover with bracket : contains (2) 10 amp ATC fuses on top .         
P2056-18126 Overload Relay IN STOCK $77.69

http://catalog.eautopartscatalog.com/mercedesshop/sophio/wizard.jsp?partner=merc...


PART NUMBER SEARCH RESULTS WITH PRICES
Vehicle 1987 Mercedes Benz 190E 2.3
Part: Fuel Pump Relay
P2037-34082 Fuel Pump Relay IN STOCK $153.38

http://catalog.eautopartscatalog.com/mercedesshop/sophio/wizard.jsp?partner=merc...


Vehicle: 1987 Mercedes Benz 190E 2.3
Part: Catalytic Converter
Select one of the products from below
    
50 States
"After-market" OBD II Catalytic Converters Not Legal for Sale in California 1995 ON         
Year:    -1988
         Catalytic Converter
Federal Only
       
Year:    -1988
         Catalytic Converter
"After-market" OBD II Catalytic Converters Not Legal for Sale in California 1995 ON         

         Catalytic Converter
Federal
"After-market" OBD II Catalytic Converters Not Legal for Sale in California 1995 ON         

http://catalog.eautopartscatalog.com/mercedesshop/sophio/wizard.jsp?partner=merc...